BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Aswin Balasubramanian (Rutgers) DTSTART:20200512T190000Z DTEND:20200512T200000Z DTSTAMP:20260422T212707Z UID:nhetc/1 DESCRIPTION:Title: Fa milies of Hitchin systems and N=2 theories\nby Aswin Balasubramanian ( Rutgers) as part of NHETC Seminar\n\n\nAbstract\nOver the last few years\, the connection between 4d N=2 theories and Hitchin systems has led to a r obust exchange of ideas between physics and mathematics. In my talk\, I wi ll explain how to extend this dictionary to one between 4d N=2 physics and the SL_N Hitchin system on a nodal UV Curve. I will then use this diction ary to clarify certain questions concerning Coulomb branches of the corres ponding Class S theories at various boundaries of the space of marginal pa rameters. In mathematical terms\, I will describe tame SL_N Hitchin system s as a flat family of integrable systems over \\bar{M}\, the Deligne-Mumfo rd moduli space of the UV Curve. This is based on upcoming work with J. Di stler and R. Donagi.\n LOCATION:https://researchseminars.org/talk/nhetc/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Ahsan Khan (Rutgers University) DTSTART:20201013T190000Z DTEND:20201013T200000Z DTSTAMP:20260422T212707Z UID:nhetc/2 DESCRIPTION:Title: Do main Wall Junctions and Categorical Wall-Crossing\nby Ahsan Khan (Rutg ers University) as part of NHETC Seminar\n\n\nAbstract\nThe wall-crossing property of BPS states is an important feature common to centrally extende d supersymmetric field theories. In this talk I will describe how the phys ics of domain wall junctions combined with elementary ideas in homological algebra leads to a categorical wall-crossing formula\; a universal descri ption of how BPS Hilbert spaces jump across a wall of marginal stability. \n\nBased on an upcoming paper with Greg Moore.\n LOCATION:https://researchseminars.org/talk/nhetc/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Ibrahima Bah (Johns Hopkins University) DTSTART:20201027T190000Z DTEND:20201027T200000Z DTSTAMP:20260422T212707Z UID:nhetc/3 DESCRIPTION:Title: An omaly Inflow and topological mass terms\nby Ibrahima Bah (Johns Hopkin s University) as part of NHETC Seminar\n\n\nAbstract\nIn this talk I will discuss the role of topological mass terms in anomaly inflow. I will cons ider QFTs obtained from brane setups in supergravity and discuss how the p resence of bulk topological mass terms are responsible for several interes ting features of the anomaly for the QFTs. In particular I will discuss h ow these terms encode the anomalies for discrete symmetries.\n LOCATION:https://researchseminars.org/talk/nhetc/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Sergei Gukov (Caltech) DTSTART:20201103T200000Z DTEND:20201103T210000Z DTSTAMP:20260422T212707Z UID:nhetc/4 DESCRIPTION:Title: Co bordism invariants from BPS q-series\nby Sergei Gukov (Caltech) as par t of NHETC Seminar\n\n\nAbstract\nMany BPS partition functions depend on a choice of additional structure: fluxes\, Spin or Spin^c structures\, etc. In a context where the BPS generating series depends on a choice of Spin^ c structure we show how different limits with respect to the expansion var iable q and different ways of summing over Spin^c structures produce diffe rent invariants of homology cobordisms out of the BPS q-series. Based on a recent work with Pavel Putrov and Sunghyuk Park.\n LOCATION:https://researchseminars.org/talk/nhetc/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Cristina Mondino (Perimeter Institute) DTSTART:20210223T180000Z DTEND:20210223T190000Z DTSTAMP:20260422T212707Z UID:nhetc/5 DESCRIPTION:Title: Pr obing dark matter substructure with astrometric weak lensing\nby Crist ina Mondino (Perimeter Institute) as part of NHETC Seminar\n\n\nAbstract\n Low-mass structures of dark matter are expected to be entirely devoid of l ight-emitting regions and baryons. Precisely because of this lack of baryo nic feedback\, small-scale substructures of the Milky Way are a relatively pristine testing ground for discovering aspects of dark matter microphysi cs and primordial fluctuations on sub-galactic scales. I will present resu lts from the first search for galactic dark matter subhalos with time-doma in astrometric weak gravitational lensing. The analysis is based on a matc hed-filter template of local lensing corrections to the proper motion of s tars in the Magellanic Clouds and is most sensitive to compact dark struct ures of ten million to a hundred million solar mass.\n LOCATION:https://researchseminars.org/talk/nhetc/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Nicholas Rodd (UC Berkeley) DTSTART:20210309T180000Z DTEND:20210309T190000Z DTSTAMP:20260422T212707Z UID:nhetc/6 DESCRIPTION:Title: Tw o new ideas for the axion dark matter program\nby Nicholas Rodd (UC Be rkeley) as part of NHETC Seminar\n\n\nAbstract\nThe coming decade will bri ng dramatic improvement in the axion dark matter program as new experiment al designs move beyond the proof of principle stage. In this talk I will o utline two new ideas that exploit this experimental progress. The first is to combine the results from two or more instruments in order to perform i nterferometry directly on the dark-matter wave. This technique reveals asp ects of the axion signal that can be invisible to a single detector\, such as the incident direction of the dark-matter wave. The second is to searc h for relativistic axions in these experiments\, in particular future inst ruments like dark-matter radio will be sensitive to axions produced in the early universe that constitute a residual Cosmic axion Background (CaB). Existing searches at\, for instance ADMX\, are not yet sensitive to a cosm ic relic\, although if relativistic axions are produce in the late univers e\, by for instance dark-matter decaying to axions\, then this is a signal the experiments are already sensitive to\, but would miss with existing a nalyses.\n LOCATION:https://researchseminars.org/talk/nhetc/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Phiala Shanahan (MIT) DTSTART:20210323T170000Z DTEND:20210323T180000Z DTSTAMP:20260422T212707Z UID:nhetc/7 DESCRIPTION:Title: Ma chine learning for physics: gauge-equivariant architectures\nby Phiala Shanahan (MIT) as part of NHETC Seminar\n\n\nAbstract\nAs machine learnin g algorithms continue to enable and accelerate physics calculations in nov el ways\, the development of tailored physics-informed machine learning ap proaches is becoming more sophisticated\, impactful\, and important. I wil l give some broad context for this developing area\, with a focus on the c hallenge of exact sampling from known probability distributions as relevan t to lattice quantum field theory calculations in particle and nuclear phy sics. I will discuss in particular flow-based generative models\, and desc ribe how guarantees of exactness and the incorporation of complex symmetri es (e.g.\, gauge symmetry) into model architectures can be achieved. I wil l show the results of proof-of-principle studies that demonstrate that sam pling from generative models can be orders of magnitude more efficient tha n traditional Hamiltonian/hybrid Monte Carlo approaches in this context.\n LOCATION:https://researchseminars.org/talk/nhetc/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Ken Van Tilburg (NYU/Flatiron CCA) DTSTART:20210406T170000Z DTEND:20210406T180000Z DTSTAMP:20260422T212707Z UID:nhetc/8 DESCRIPTION:Title: St ellar Basins of Gravitationally Bound Particles\nby Ken Van Tilburg (N YU/Flatiron CCA) as part of NHETC Seminar\n\n\nAbstract\nI will describe a nd explore the consequences of a peculiar physical phenomenon: volumetric stellar emission into gravitationally bound orbits of weakly coupled parti cles such as axions\, moduli\, hidden photons\, and neutrinos. While only a tiny fraction of the instantaneous luminosity of a star (the vast majori ty of the emission is into relativistic modes)\, the continual injection o f these particles into a small part of phase space causes them to accumula te over astrophysically long time scales\, forming what I call a "stellar basin"\, in analogy with the geologic kind. The energy density of the Sola r basin can surpass that of the relativistic Solar flux at Earth's locatio n after only a million years\, for any sufficiently long-lived particle pr oduced through an emission process whose matrix elements are unsuppressed at low momentum. This observation has immediate and striking consequences for direct detection experiments---including new limits on axion and hidde n-photon parameter space independent of dark matter assumptions---and open s up prospects for indirect detection of weakly interacting particles arou nd stars. [Based on https://arxiv.org/abs/2006.12431 and https://arxiv.org /abs/2008.08594\, and ongoing work.]\n LOCATION:https://researchseminars.org/talk/nhetc/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Jeff Dror (UC Santa Cruz) DTSTART:20210420T170000Z DTEND:20210420T180000Z DTSTAMP:20260422T212707Z UID:nhetc/9 DESCRIPTION:Title: Te sting fundamental physics using pulsars\nby Jeff Dror (UC Santa Cruz) as part of NHETC Seminar\n\n\nAbstract\nA pulsar is a star that can rotate as fast as a thousand times per second\, with each rotation sending a bea m of light at our telescopes. The arrival time of each pulse is dependent on the Earth's motion\, opening an opportunity to search for gravitational waves shaking the Earth with frequencies of O(year^-1). In this talk\, I will show how these datasets can be used to probe fundamental physics focu sing both on types of signals to search for as well as how recent developm ents in machine learning can be employed to greatly expand the range of se arches carried out by pulsar timing experiments. These searches are partic ularly timely due to the recent detection of a correlated signal across ma ny pulsars\, which may be our first glimpse of gravitational waves from su permassive black hole mergers.\n LOCATION:https://researchseminars.org/talk/nhetc/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Jared Kaplan (Johns Hopkins University) DTSTART:20210126T183000Z DTEND:20210126T193000Z DTSTAMP:20260422T212707Z UID:nhetc/10 DESCRIPTION:Title: S caling Laws in Machine Learning and GPT-3\nby Jared Kaplan (Johns Hopk ins University) as part of NHETC Seminar\n\n\nAbstract\nA variety of recen t works suggest that scaling laws are ubiquitous in machine learning. In particular\, neural network performance obeys scaling laws with respect to the number of parameters\, dataset size\, and the training compute budget . I will explain these scaling laws\, and argue that they are both precis e and very universal. Then I will explain how this line of thinking led t o the GPT-3 language model\, and what it suggests for the future.\n LOCATION:https://researchseminars.org/talk/nhetc/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Harikrishnan Ramani (Stanford University) DTSTART:20210209T183000Z DTEND:20210209T193000Z DTSTAMP:20260422T212707Z UID:nhetc/11 DESCRIPTION:Title: T ackling energy deficits for dark matter detection\nby Harikrishnan Ram ani (Stanford University) as part of NHETC Seminar\n\n\nAbstract\nModels s uch as inelastic dark matter\, dark matter with large interactions with th e standard model\, and dark matter with masses below 1 MeV are notoriously difficult to detect in direct detection experiments owing to their inabil ity to impart a large enough recoil energy in traditional dark matter expe riments. In this talk\, I explore different strategies to attack this prob lem. These include nuclear isomer batteries\, electric fields to accelerat e milli-charge dark matter and atoms and molecules with small energy gaps. \n LOCATION:https://researchseminars.org/talk/nhetc/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Emil Martinec (University of Chicago) DTSTART:20210413T170000Z DTEND:20210413T180000Z DTSTAMP:20260422T212707Z UID:nhetc/12 DESCRIPTION:Title: S tringy Structure at the BPS Bound\nby Emil Martinec (University of Chi cago) as part of NHETC Seminar\n\n\nAbstract\nWorldsheet string theory pai nts a picture of BPS and near-BPS states of NS5-branes. We employ a class of 1/2-BPS states having an exactly solvable worldsheet description in te rms of gauged WZW models to explore the stringy properties of these states . Consequences for black hole formation will also be discussed.\n LOCATION:https://researchseminars.org/talk/nhetc/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Brian Nord (Fermilab) DTSTART:20210504T170000Z DTEND:20210504T180000Z DTSTAMP:20260422T212707Z UID:nhetc/13 DESCRIPTION:Title: D eeply Uncertain: (how) can we make deep learning tools trustworthy for sci entific measurements?\nby Brian Nord (Fermilab) as part of NHETC Semin ar\n\n\nAbstract\nArtificial Intelligence (AI) --- including machine learn ing and deep learning --- refers to a set of techniques that rely primaril y on the data itself for the construction of a quantitative model. AI has been in development for about three quarters of a century\, but there has been a recent resurgence in research and applications. This current (third ) wave of AI progress is marked by extraordinary results --- for example\, in image analysis\, language translation\, and machine automation. Despit e the modest definition of AI\, its potential to disrupt technologies\, ec onomies\, society\, and even science is often presented as unmatched in mo dern times. However\, along with the promise of AI\, there are significant challenges to overcome to reach a degree of reliability that is on par wi th more traditional modeling methods. \nIn particular\, uncertainty quanti fication metrics derived from deep neural networks are yet to be made phys ically interpretable. For example\, when one uses a convolutional neural n etwork to measure values from an image (e.g.\, regression for galaxy prope rties)\, the error estimates do not necessarily match those from an MCMC l ikelihood fit. In this presentation\, I will discuss the landscape of unce rtainty quantification in deep learning\, as well as some computational ex periments in a physical context that demonstrate a mismatch between errors derived directly from deep learning methods and those derived through tra ditional error propagation. Before we can apply deep learning tools confid ently for the direct measurement of physical properties\, we’ll need sta tistically robust error estimation methods.\n LOCATION:https://researchseminars.org/talk/nhetc/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Tongyan Lin DTSTART:20210907T170000Z DTEND:20210907T180000Z DTSTAMP:20260422T212707Z UID:nhetc/14 DESCRIPTION:Title: D ark matter direct detection with dielectrics\nby Tongyan Lin as part o f NHETC Seminar\n\n\nAbstract\nDirect detection experiments are rapidly ad vancing in the search for sub-GeV dark matter. As energy thresholds become lower\, the many-body physics of a target material becomes especially imp ortant in determining a dark matter signal. In this talk\, I will discuss how dark matter interactions in dielectric materials can be understood in terms of the dielectric response\, or energy loss function (ELF). This pro vides a useful framework for dark matter direct detection and also allows us to calculate some new effects. I will discuss various applications of t his\, including screening effects for dark matter electron scattering\, ph onon creation\, and the Migdal effect in semiconductors.\n LOCATION:https://researchseminars.org/talk/nhetc/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Shu-Heng Shao (YITP\, Stony Brook University) DTSTART:20210914T170000Z DTEND:20210914T180000Z DTSTAMP:20260422T212707Z UID:nhetc/15 DESCRIPTION:Title: O n topological boundary conditions in 2+1d TQFT\nby Shu-Heng Shao (YITP \, Stony Brook University) as part of NHETC Seminar\n\n\nAbstract\nA 2+1-d imensional topological quantum field theory (TQFT) may or may not admit to pological (gapped) boundary conditions. In this talk\, we consider obstruc tions to the existence of a topological boundary condition from the "highe r" central charges\, which have been introduced recently in the math liter ature. In terms of these new obstructions\, we identify necessary and suff icient conditions for the existence of a topological boundary in the case of bosonic\, Abelian TQFTs\, providing an alternative to the identificatio n of a Lagrangian subgroup. Our proof relies on general aspects of gauging generalized global symmetries.\n LOCATION:https://researchseminars.org/talk/nhetc/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Whiteson (University of California\, Irvine) DTSTART:20210921T170000Z DTEND:20210921T180000Z DTSTAMP:20260422T212707Z UID:nhetc/16 DESCRIPTION:Title: L earning Particle Physics from Machines\nby Daniel Whiteson (University of California\, Irvine) as part of NHETC Seminar\n\n\nAbstract\nRecent ad vances in artificial intelligence offer opportunities to disrupt the tradi tional strategies for discovery of new particles in high energy collisions . I will describe the new machine-learning techniques\, explain why they are particularly well suited for particle physics\, present selected resul ts that demonstrate their new capabilities\, and present a strategy for tr anslating their learned strategies into human understanding. \n\nBio: D aniel Whiteson is a professor of experimental particle physics at the Univ ersity of California\, Irvine\, and a fellow of the American Physical Soci ety. He conducts research using the Large Hadron Collider at CERN. He rec eived his PhD at Berkeley.\n LOCATION:https://researchseminars.org/talk/nhetc/16/ END:VEVENT BEGIN:VEVENT SUMMARY:John McGreevy (University of California\, San Diego) DTSTART:20210928T183000Z DTEND:20210928T193000Z DTSTAMP:20260422T212707Z UID:nhetc/17 DESCRIPTION:Title: F ractons and Chern-Simons Theory\nby John McGreevy (University of Calif ornia\, San Diego) as part of NHETC Seminar\n\n\nAbstract\nAfter discussin g some reasons that fractons are interesting\, I will talk about a version of dimensional deconstruction that produces 3+1d fracton phases. This con struction provides examples beyond those known from solvable lattice model s\, and a possible route to realize them in experiments.\n\nBased on 2010. 08917 with Xiuqi Ma\, Wilbur Shirley\, Meng Cheng\, Michael Levin and Xie Chen.\n LOCATION:https://researchseminars.org/talk/nhetc/17/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Harlow (MIT) DTSTART:20211012T160000Z DTEND:20211012T170000Z DTSTAMP:20260422T212707Z UID:nhetc/18 DESCRIPTION:Title: A universal formula for the density of states in theories with finite-group symmetry\nby Daniel Harlow (MIT) as part of NHETC Seminar\n\n\nAbstra ct\nIn this paper we use Euclidean gravity to derive a simple formula for the density of black hole microstates which transform in each irreducible representation of any finite gauge group. Since each representation appear s with nonzero density\, this\ngives a new proof of the completeness hypot hesis for finite gauge fields. Inspired by the generality of the argument we further propose that the formula applies at high energy in any quantum field theory with a finite-group global symmetry\, and give some evidence for this conjecture.\n LOCATION:https://researchseminars.org/talk/nhetc/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Davide Gaiotto (Perimeter Institute) DTSTART:20211026T183000Z DTEND:20211026T193000Z DTSTAMP:20260422T212707Z UID:nhetc/19 DESCRIPTION:Title: G iant gravitons in twisted holograpy\nby Davide Gaiotto (Perimeter Inst itute) as part of NHETC Seminar\n\n\nAbstract\nI will demonstrate the emer gence of bulk geometric structures in a simple\, essentially free\, toy mo del for holography.\n LOCATION:https://researchseminars.org/talk/nhetc/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Ofri Telem (LBNL Physics Division) DTSTART:20211102T183000Z DTEND:20211102T193000Z DTSTAMP:20260422T212707Z UID:nhetc/20 DESCRIPTION:Title: M onopole Catalysis From Scattering Amplitudes\nby Ofri Telem (LBNL Phys ics Division) as part of NHETC Seminar\n\n\nAbstract\nUsing our novel cons truction of the S-matrix for the scattering of electric and magnetic charg es\, we address the notoriously confusing effect of Monopole Catalysis. In particular\, we provide an on-shell derivation of the Rubakov-Callan effe ct\, as well as address the famous “monopole unitarity paradox” - wher e there seems to be no valid final state in the scattering of a positron w ith a GUT monopole. Our proposed final state involves 3 fermions with tota l J=0\, which conserve all SM quantum numbers and can escape the core by v irtue of their entanglement with the monopole.\n LOCATION:https://researchseminars.org/talk/nhetc/20/ END:VEVENT BEGIN:VEVENT SUMMARY:Brian Swingle (MIT) DTSTART:20211109T193000Z DTEND:20211109T203000Z DTSTAMP:20260422T212707Z UID:nhetc/21 DESCRIPTION:Title: H ydrodynamics and the Spectral Form Factor\nby Brian Swingle (MIT) as p art of NHETC Seminar\n\n\nAbstract\nEnsembles of quantum chaotic systems a re expected to exhibit random matrix universality in their energy spectrum . The presence of this universality can be diagnosed by looking for a line ar in time 'ramp' in the spectral form factor\, but for realistic systems this feature is typically only visible after a sufficiently long time. It is important to understand the emergence of this universality and how it c onnects to the larger body of phenomena associated with quantum chaos. Thi s talk will present a hydrodynamic theory of the spectral form factor in s ystems with slow modes. The formalism predicts the linear ramp at sufficie ntly late time and gives a quantitative framework for computing the approa ch to ramp.\n LOCATION:https://researchseminars.org/talk/nhetc/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Katelin Schutz (McGill Space Institute) DTSTART:20211116T193000Z DTEND:20211116T203000Z DTSTAMP:20260422T212707Z UID:nhetc/22 DESCRIPTION:Title: A strophysical plasmas\, phase space\, and searches for new particles\nb y Katelin Schutz (McGill Space Institute) as part of NHETC Seminar\n\n\nAb stract\nAstrophysical plasmas can be an abundant source of particles with a small coupling to photons\, for instance in dark sectors with a kinetica lly mixed U(1). In many situations\, the decay of plasmons (photons with a n in-medium effective mass) is the most efficient process for generating n ew kinds of particles. In this talk\, I will discuss two distinct examples : the production of gravitationally bound particles in the sun and the fre eze-in of dark matter in the early Universe. In the former case\, I will s how how gravitationally bound particles from the sun may be detectable wit h an experimental setup that coherently deflects the solar MCP wind\, gene rating an oscillating electric field in a shielded detector. In the latter case\, I will show that dark matter freeze-in from plasmon decay may be d etectable through its cosmological clustering and through a drag effect im parted on the photon-baryon fluid prior to recombination. If there is suff icient time\, I will also discuss the detection of axion dark matter decay that is stimulated by the synchrotron radiation coming from the plasma su ffusing supernova remnants. In all of these examples\, the unique phase sp ace of new particles provides the main observational handle for discovery. \n LOCATION:https://researchseminars.org/talk/nhetc/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Geoff Penington (UC Berkeley) DTSTART:20211130T193000Z DTEND:20211130T203000Z DTSTAMP:20260422T212707Z UID:nhetc/24 DESCRIPTION:Title: Q uantum minimal surfaces from quantum error correction\nby Geoff Pening ton (UC Berkeley) as part of NHETC Seminar\n\n\nAbstract\nWe show that com plementary state-specific reconstruction of logical (bulk) operators is eq uivalent to the existence of a quantum minimal surface prescription for ph ysical (boundary) entropies. This significantly generalizes both sides of an equivalence previously shown by Harlow\; in particular\, we do not requ ire the entanglement wedge to be the same for all states in the code space . In developing this theorem\, we construct an emergent bulk geometry for general quantum codes\, defining "areas" associated to arbitrary logical s ubsystems\, and argue that this definition is "functionally unique." We al so formalize a definition of bulk reconstruction that we call "state-speci fic product unitary" reconstruction. This definition captures the quantum error correction (QEC) properties present in holographic codes and has pot ential independent interest as a very broad generalization of QEC\; it inc ludes most traditional versions of QEC as special cases. Our results exten d to approximate codes\, and even to the "non-isometric codes" that seem t o describe the interior of a black hole at late times.\n LOCATION:https://researchseminars.org/talk/nhetc/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Rebecca Leane (SLAC) DTSTART:20211207T193000Z DTEND:20211207T203000Z DTSTAMP:20260422T212707Z UID:nhetc/25 DESCRIPTION:Title: D etecting Dark Matter in Celestial Bodies\nby Rebecca Leane (SLAC) as p art of NHETC Seminar\n\n\nAbstract\nStars and planets can be ideal playgro unds to discover dark matter. In this talk\, I will review a range of dark matter searches using celestial objects\, including neutron stars\, exopl anets\, solar-system planets\, and our Sun. I will discuss different searc h strategies\, their opportunities and limitations\, and the interplay of regimes where different celestial objects are optimal detectors.\n LOCATION:https://researchseminars.org/talk/nhetc/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Patrick Draper (University of Illinois) DTSTART:20211005T183000Z DTEND:20211005T193000Z DTSTAMP:20260422T212707Z UID:nhetc/26 DESCRIPTION:Title: T he CKN Bound and Particle Physics\nby Patrick Draper (University of Il linois) as part of NHETC Seminar\n\n\nAbstract\nThe holographic principle implies that quantum field theory overcounts the number of independent deg rees of freedom in quantum gravity. An argument due to Cohen\, Kaplan\, an d Nelson (CKN) suggests that the number of degrees of freedom well-describ ed by QFT is even smaller than required by holographic bounds\, and CKN in terpreted this result as indicative of a correlation between the UV and IR cutoffs on QFT. We consider an alternative interpretation in which the QF T degrees of freedom are depleted as a function of scale\, and we use a si mple recipe to estimate the impact of depleted densities of states on prec ision observables. Although these observables are not sensitive to the lev el of depletion motivated by gravitational considerations\, the phenomenol ogical exercises also provide an interesting test of QFT that is independe nt of underlying quantum gravity assumptions. A depleted density of states can also render the QFT vacuum energy UV-insensitive\, reconciling the su ccess of QFT in describing ordinary particle physics processes and its app arent failure in predicting the cosmological constant.\n LOCATION:https://researchseminars.org/talk/nhetc/26/ END:VEVENT BEGIN:VEVENT SUMMARY:Siddharth Mishra-Sharma (MIT) DTSTART:20211019T183000Z DTEND:20211019T193000Z DTSTAMP:20260422T212707Z UID:nhetc/27 DESCRIPTION:Title: U sing machine learning to look for dark matter in the Galactic Center\, the Milky Way halo\, and other galaxies\nby Siddharth Mishra-Sharma (MIT) as part of NHETC Seminar\n\n\nAbstract\nAdvancements in machine learning have enabled new ways of doing inference on forward models defined through complex\, high-dimensional simulations. After briefly motivating their us e in the cosmological context\, I will present applications of these simul ation-based inference methods to three separate astrophysical systems with the goal of looking for signatures of dark matter. First\, I will describ e how they can be used to combine information from thousands of strong gra vitational lensing systems in a principled way in order to extract the pop ulation properties of dark matter. Then\, I will quantify their sensitivit y to the collective imprint of dark matter subhalos in our own Galaxy on t he measured motions of background luminous celestial objects. Finally\, I will present an application to the Galactic Center gamma-ray excess\, wher e the fact that our method can extract more information from the gamma-ray dataset than is possible with traditional techniques can be used to more robustly characterize the nature of the excess and constrain its dark matt er properties.\n LOCATION:https://researchseminars.org/talk/nhetc/27/ END:VEVENT BEGIN:VEVENT SUMMARY:Juven Wang (Harvard) DTSTART:20211123T193000Z DTEND:20211123T203000Z DTSTAMP:20260422T212707Z UID:nhetc/28 DESCRIPTION:Title: Q uantum Criticality Beyond the Standard Model and Ultra Unification\nby Juven Wang (Harvard) as part of NHETC Seminar\n\n\nAbstract\nWe propose a theory [arXiv:2012.15860] beyond the Standard Model (SM) and Grand Unific ation (GUT) with 15n Weyl fermions by adding new gapped Topological Phase Sectors based on nonperturbative global anomaly cancellations and cobordis m constraints (especially from the baryon minus lepton number B − L \, t he electroweak hypercharge Y\, and the Z_{16} class mixed gauge-gravitatio nal anomaly). Gapped topological phase sectors are constructed via symmetr y extension (in contrast with the Anderson-Higgs symmetry breaking)\, whos e low energy contains unitary Lorentz invariant topological quantum field theories (TQFTs): either (3+1)d noninvertible TQFT\, or (4+1)d invertible or noninvertible TQFT (short-range or long-range entangled gapped phase). Alternatively\, there could also be right-handed neutrinos\, or gapless un particle conformal field theories\, or their combinations to altogether ca ncel the mixed gauge-gravitational anomaly. We also introduce an alternati ve view [arXiv:2106.16248] that the SM is a low-energy quantum vacuum aris ing from various neighbor GUT vacua competition in an immense quantum phas e diagram. In particular\, we demonstrate how the su(3)×su(2)×u(1) SM wi th 16n Weyl fermions arose near the quantum criticality between the compet ition of Georgi-Glashow su(5) model and Pati-Salam su(4)×su(2)×su(2) mod el. Moreover\, to manifest a Beyond-the-Standard-Model (BSM) and Beyond-La ndau-Ginzburg deconfined quantum criticality between Georgi-Glashow and Pa ti-Salam models\, we introduce a parent effective field theory of a modifi ed so(10) GUT (with a Spin(10) gauge group) plus a new 4d discrete torsion class of Wess-Zumino-Witten-like term that saturates a Z_2 class global m ixed gauge-gravity anomaly captured by a 5d invertible topological field t heory w2w3(TM)=w2w3(VSO(10)). We show new fractionalized excitations of Co lor-Flavor separation\, and gauge enhancement including a Dark Gauge force sector\, or gauge-enhanced 4d criticality as a boundary criticality such that only appropriately gauge enhanced dynamical GUT gauge fields can prop agate into an extra-dimensional 5d bulk.\n\nThe talk is mainly based on ar Xiv:2012.15860\, arXiv:2106.16248\, and arXiv:2111.10369 (with Yi-Zhuang Y ou).\n LOCATION:https://researchseminars.org/talk/nhetc/28/ END:VEVENT BEGIN:VEVENT SUMMARY:Anton Kapustin (Caltech) DTSTART:20220222T193000Z DTEND:20220222T203000Z DTSTAMP:20260422T212707Z UID:nhetc/29 DESCRIPTION:Title: E quivariant Berry phase for many-body quantum lattice systems\nby Anton Kapustin (Caltech) as part of NHETC Seminar\n\n\nAbstract\nBerry phase as originally defined makes sense only for quantum systems with a finite-dim ensional Hilbert space. However\, it does have important generalizations t o many-body systems. In this talk I will describe some generalizations of the Berry phase to the case of quantum lattice systems in infinite volume. The Hall conductance and its nonabelian versions emerge as special cases. The results can be viewed as a generalizations of the von Neumann - Wigne r theorem on level crossing in quantum systems.\n LOCATION:https://researchseminars.org/talk/nhetc/29/ END:VEVENT BEGIN:VEVENT SUMMARY:Hank Lamm (Fermilab) DTSTART:20220201T193000Z DTEND:20220201T203000Z DTSTAMP:20260422T212707Z UID:nhetc/30 DESCRIPTION:Title: Q uantum Computing for Quantum Field Theories\nby Hank Lamm (Fermilab) a s part of NHETC Seminar\n\n\nAbstract\nThe advent of quantum computation p resents the opportunity to solve questions in physics which are inaccessib le to classical computation such as real-time evolution and the equation o f state at finite density. In order to take advantage of this new resource \, a number of theoretical and computational hurdles will need to be addre ssed. In this talk\, I will discuss the state of the art research being p erformed in quantum field theory and outstanding questions that require ou r attention going forward\, focusing on digitization of lattice gauge theo ries and extracting physical results that demonstrate practical quantum ad vantage.\n LOCATION:https://researchseminars.org/talk/nhetc/30/ END:VEVENT BEGIN:VEVENT SUMMARY:Graham White (University of Tokyo) DTSTART:20220215T213000Z DTEND:20220215T223000Z DTSTAMP:20260422T212707Z UID:nhetc/31 DESCRIPTION:Title: A rchaeology on the origin of matter\nby Graham White (University of Tok yo) as part of NHETC Seminar\n\n\nAbstract\nOne of the most convincing rea sons to expect physics beyond\nthe Standard model is the inbalance between matter and anti-matter. Some\nfantastic paradigms exist that can be probe d at a low scale including\nelectroweak baryogenesis\, mesogenesis and res onant leptogenesis. While\nthese paradigms or worthy of dedicated attentio n\, the elephant in the\nroom is that there are two paradigms that are ver y minimal and involve\nphysics at scales we cannot possibly reach with Ear th based colliders in\nour life time. I will first discuss the nightmare s cenario of thermal\nleptogenesis implemented with no BSM particle content beyond sterile\nneutrinos and an inflaton. In this case\, measurements of the top and\nHiggs mass along with inflationary observables can shed some light on\nthe plausibility\, or lack thereof\, of vanilla leptogenesis. I will then\ndiscuss the GUT leptogenesis and Affleck Dine baryogenesis. I a rgue in\nboth these cases there are generic predictions of a primordial\ng ravitational wave background that can be measured today. The presence\nof such a signal would lend plausibility to one of these scenarios.\nFinally I discuss the discriminating power of GWs in discerning the\nsymmetry bre aking path through the variable signals of hybrid defects.\n LOCATION:https://researchseminars.org/talk/nhetc/31/ END:VEVENT BEGIN:VEVENT SUMMARY:Clara Murgui (Caltech) DTSTART:20220301T193000Z DTEND:20220301T203000Z DTSTAMP:20260422T212707Z UID:nhetc/32 DESCRIPTION:Title: D ark Unification: a UV-complete Theory of Asymmetric Dark Matter\nby Cl ara Murgui (Caltech) as part of NHETC Seminar\n\n\nAbstract\nMotivated by the observed ratio of dark matter to baryon mass densities\, which is arou nd a factor 5\, we propose a theory of dark-color unification. In this the ory\, the dark to visible baryon masses are fixed by the ratio of dark to visible confinement scales\, which are determined to be nearby in mass thr ough the unification of the dark and visible gauge theories at a high scal e. Together with a mechanism for darko-baryo-genesis\, which arises natura lly from the grand unification sector\, the mass densities of the two sect ors must be nearby\, explaining the observed mass density of dark matter. We focus on the simplest possible example of such a theory\, where Standar d Model color SU(3)c is unified with dark color SU(2)D into SU(5) at an in termediate scale of around 10^8 -10^9 GeV. The dark baryon consists of two dark quarks in an isotriplet configuration. There are a range of importan t cosmological\, astrophysical and collider signatures to explore\, includ ing dark matter self-interactions\, early matter domination from the dark hadrons\, gravitational wave signatures from the hidden sector phase trans ition\, contributions to flavor observables\, as well as Hidden Valley-lik e signatures at colliders.\n LOCATION:https://researchseminars.org/talk/nhetc/32/ END:VEVENT BEGIN:VEVENT SUMMARY:Tudor Dimofte (UC Davis and University of Edinburgh) DTSTART:20220308T193000Z DTEND:20220308T203000Z DTSTAMP:20260422T212707Z UID:nhetc/33 DESCRIPTION:Title: A QFT for non-semisimple TQFT\nby Tudor Dimofte (UC Davis and Universit y of Edinburgh) as part of NHETC Seminar\n\n\nAbstract\nTopological twists of 3d N=4 gauge theories naturally give rise to non-semisimple 3d TQFT's. In mathematics\, prototypical examples of the latter were constructed in the 90's (by Lyubashenko and others) from representation categories of sma ll quantum groups at roots of unity\; they were recently generalized in wo rk of Costantino-Geer-Patureau Mirand and collaborators. I will introduce a family of physical 3d quantum field theories that (conjecturally) reprod uce these classic non-semisimple TQFT's. The physical theories combine Che rn-Simons-like and 3d N=4-like sectors. They are also related to Feigin-Ti punin vertex algebras\, much the same way that Chern-Simons theory is rela ted to WZW vertex algebras.\n(Based on work with T. Creutzig\, N. Garner\, and N. Geer.)\n LOCATION:https://researchseminars.org/talk/nhetc/33/ END:VEVENT BEGIN:VEVENT SUMMARY:Greg Yang (Microsoft Research) DTSTART:20220322T183000Z DTEND:20220322T193000Z DTSTAMP:20260422T212707Z UID:nhetc/34 DESCRIPTION:Title: R enormalizing the Optimal Hyperparameters of a Neural Network\nby Greg Yang (Microsoft Research) as part of NHETC Seminar\n\n\nAbstract\nHyperpar ameter tuning in deep learning is an expensive process\, prohibitively so for neural networks (NNs) with billions of parameters that often can only be trained once. We show that\, in the recently discovered Maximal Update Parametrization (μP)\, many optimal hyperparameters remain stable even as model size changes. Using this insight\, for example\, we are able to re -tune the 6.7-billion-parameter model of GPT-3 and obtain performance comp arable to the 13-billion-parameter model of GPT-3\, effectively doubling t he model size.\n\nIn this context\, there is a rich analogy we can make to Wilsonian effective field theory. For example\, if “coupling constants ” in physics correspond to “optimal hyperparameters” in deep learnin g and “cutoff scale” corresponds to “model size”\, then we can say “μP is a renormalizable theory of neural networks.” We finish by for mulating the question of whether there is a “Grand Unifying Theory” of neural networks at scale that can inform our quest toward general intelli gence.\n LOCATION:https://researchseminars.org/talk/nhetc/34/ END:VEVENT BEGIN:VEVENT SUMMARY:Andy Neitzke (Yale University) DTSTART:20220329T183000Z DTEND:20220329T193000Z DTSTAMP:20260422T212707Z UID:nhetc/35 DESCRIPTION:Title: D ifferential equations and deformations of supersymmetric QFT\nby Andy Neitzke (Yale University) as part of NHETC Seminar\n\n\nAbstract\nThere is a connection between N=2 supersymmetric field theory in four dimensions a nd the theory of linear differential and difference equations with meromor phic coefficients. This connection is surprisingly rich\, and has been stu died by many different authors from different perspectives. One way of und erstanding it is as an instance of the general phenomenon that turning on Omega-background naturally quantizes algebraic structures in the operator algebras of supersymmetric QFT. I will recall this connection and describe some of its uses\, along with some recent and ongoing extensions of the s tory.\n LOCATION:https://researchseminars.org/talk/nhetc/35/ END:VEVENT BEGIN:VEVENT SUMMARY:Ian Moult (Yale University) DTSTART:20220405T183000Z DTEND:20220405T193000Z DTSTAMP:20260422T212707Z UID:nhetc/36 DESCRIPTION:Title: C onformal Colliders Meet the LHC\nby Ian Moult (Yale University) as par t of NHETC Seminar\n\n\nAbstract\nJets of hadrons produced at high-energy colliders provide experimental access to the dynamics of asymptotically fr ee quarks and gluons and their confinement into hadrons. Motivated by rece nt developments in conformal field theory\, we propose a reformulation of jet substructure as the study of correlation functions of a specific class of light-ray operators and their associated operator product expansion (O PE). We show that multi-point correlation functions of these operators can be measured in real LHC data\, allowing us to experimentally verify prope rties of the light-ray OPE. We then discuss how this reformulation provide s new ways of experimentally studying the Standard Model at colliders\, as well as new theoretical techniques for performing calculations in QCD.\n LOCATION:https://researchseminars.org/talk/nhetc/36/ END:VEVENT BEGIN:VEVENT SUMMARY:Du Pei (Harvard) DTSTART:20220412T183000Z DTEND:20220412T193000Z DTSTAMP:20260422T212707Z UID:nhetc/37 DESCRIPTION:Title: H olomorphic CFTs and topological modular forms\nby Du Pei (Harvard) as part of NHETC Seminar\n\n\nAbstract\nThe theory of topological modular for ms leads to many interesting constraints and predictions for two-dimension al quantum field theories. In this talk\, I will show that a conjecture by Segal\, Stolz and Teichner requires the constant term of the partition fu nction of a bosonic holomorphic CFTs to be divisible by specific integers determined by the central charge. We verify this constraint in large class es of physical examples\, and rule out the existence of an infinite set of "extremal CFTs"\, including those with central charges c = 48\, 72\, 96 a nd 120.\n LOCATION:https://researchseminars.org/talk/nhetc/37/ END:VEVENT BEGIN:VEVENT SUMMARY:Joshua Isaacson (Fermilab) DTSTART:20220419T183000Z DTEND:20220419T193000Z DTSTAMP:20260422T212707Z UID:nhetc/38 DESCRIPTION:Title: H ow to measure M_W: A theory perspective\nby Joshua Isaacson (Fermilab) as part of NHETC Seminar\n\n\nAbstract\nWith the recent CDF-II W mass mea surement\, many questions have arisen about the accuracy and procedure of extracting the W mass. In this talk\, I will cover the details of the ResB os calculation used by the CDF experiment\, along with details on the proc edure of extracting the W mass and the associated theory uncertainties.\n LOCATION:https://researchseminars.org/talk/nhetc/38/ END:VEVENT BEGIN:VEVENT SUMMARY:Pietro Longhi (Uppsala University) DTSTART:20220426T183000Z DTEND:20220426T193000Z DTSTAMP:20260422T212707Z UID:nhetc/39 DESCRIPTION:Title: S tudies of five-dimensional BPS spectra and applications to enumerative geo metry\nby Pietro Longhi (Uppsala University) as part of NHETC Seminar\ n\n\nAbstract\nThe framework of spectral networks was introduced in physic s as a way to compute BPS states of 4d N=2 gauge theories. In this talk I will review an extension of this framework\, known as exponential networks \, which arises in the study of 5d N=1 BPS states. Geometric engineering c onnects 5d N=1 BPS spectra to enumerative invariants of certain Calabi-Yau threefolds\, I will review the computation of old and new results in the setting of local toric threefolds. I will also sketch a new perspective on this framework\, which elucidates the geometric meaning of the invariants computed by networks\, in terms of elementary data of A-branes in the mir ror geometry\, recovering an old conjecture of Joyce.\n LOCATION:https://researchseminars.org/talk/nhetc/39/ END:VEVENT BEGIN:VEVENT SUMMARY:Anja Butter (ITP in Heidelberg) DTSTART:20220503T183000Z DTEND:20220503T193000Z DTSTAMP:20260422T212707Z UID:nhetc/40 DESCRIPTION:Title: N ormalizing Flows for LHC Theory\nby Anja Butter (ITP in Heidelberg) as part of NHETC Seminar\n\n\nAbstract\nOver the next years\, measurements a t the LHC and the HL-LHC will provide us with a wealth of new data. The be st hope to answer fundamental questions\, like the nature of dark matter\, is to adopt big data techniques in simulations and analyses to extract al l relevant information. On the theory side\, LHC physics crucially relies on our ability to simulate events efficiently from first principles. These simulations will face unprecedented precision requirements to match the e xperimental accuracy. Innovative ML techniques like generative models can help us overcome limitations from the high dimensionality of the phase spa ce. Such networks can be employed to directly simulate events or to suppor t first principle calculations like multi-loop amplitudes. Since neural ne tworks can be inverted\, they open new avenues in LHC analyses.\n LOCATION:https://researchseminars.org/talk/nhetc/40/ END:VEVENT BEGIN:VEVENT SUMMARY:Dalimil Mazac (IAS) DTSTART:20220208T193000Z DTEND:20220208T203000Z DTSTAMP:20260422T212707Z UID:nhetc/41 DESCRIPTION:Title: A utomorphic Spectra and the Conformal Bootstrap\nby Dalimil Mazac (IAS) as part of NHETC Seminar\n\n\nAbstract\nI will explain that the spectral geometry of hyperbolic manifolds provides a remarkably faithful model of t he modern conformal bootstrap. In particular\, to each hyperbolic D-manifo ld\, one can associate a Hilbert space of local operators\, which is a uni tary representation of a conformal group. The local operators live in an e mergent (D-1)-dimensional spacetime. The scaling dimensions of the operato rs are related to the eigenvalues of the Laplacian on the manifold. The op erators satisfy an operator product expansion. Finally\, one can define th eir correlation functions and derive bootstrap equations constraining the spectrum. As an application\, I will use conformal bootstrap techniques to derive upper bounds on the lowest positive eigenvalue of the Laplacian on closed hyperbolic surfaces and 2-orbifolds. In a number of notable cases\ , the bounds are nearly saturated by known surfaces and orbifolds. For ins tance\, the bound on all genus-2 surfaces is λ1≤3.8388976481\, while th e Bolza surface has λ1≈3.838887258. The talk will be based on https://a rxiv.org/abs/2111.12716\, which is joint work with P. Kravchuk and S. Pal. \n LOCATION:https://researchseminars.org/talk/nhetc/41/ END:VEVENT BEGIN:VEVENT SUMMARY:Peizhi Du (Stony Brook University) DTSTART:20220315T183000Z DTEND:20220315T193000Z DTSTAMP:20260422T212707Z UID:nhetc/42 DESCRIPTION:Title: N ew backgrounds and new ideas for sub-GeV dark matter direct detection\ nby Peizhi Du (Stony Brook University) as part of NHETC Seminar\n\n\nAbstr act\nProbing sub-GeV dark matter requires designing low threshold detector s and understanding backgrounds. In this talk I will address these two iss ues. First\, we point out several unexplored low-energy backgrounds in sub -GeV dark matter searches\, which arise from high-energy particles of cosm ic or radioactive origin that interact with detector materials. In this ta lk\, I will focus on Cherenkov radiation and luminescence from electron-ho le pair recombination. We demonstrate that these processes provide plausib le explanations of the observed events at SENSEI and SuperCDMS HVeV. Secon d\, we propose a new idea of probing light dark matter using doped semicon ductors. Dopants in semiconductors form energy levels that are tens of meV below the conduction band or above the valence band. These materials can be new detector targets for dark matter scattering with a threshold of ten s of meV\, which can probe dark matter masses down to tens of keV.\n LOCATION:https://researchseminars.org/talk/nhetc/42/ END:VEVENT BEGIN:VEVENT SUMMARY:Prasanth Shyamsundar (Fermilab) DTSTART:20220517T183000Z DTEND:20220517T193000Z DTSTAMP:20260422T212707Z UID:nhetc/43 DESCRIPTION:Title: C onstructing sensitive and robust collider observables with machine learnin g\nby Prasanth Shyamsundar (Fermilab) as part of NHETC Seminar\n\n\nAb stract\nI will discuss some concluded and ongoing work on constructing\, u sing machine learning\, sensitive low-dimensional variables for use in col lider data analyses. I will also briefly discuss the robustness offered by the technique against unknown and unquantified errors in the simulation m odels.\n LOCATION:https://researchseminars.org/talk/nhetc/43/ END:VEVENT BEGIN:VEVENT SUMMARY:Sameer Murthy (King's College London) DTSTART:20220920T183000Z DTEND:20220920T193000Z DTSTAMP:20260422T212707Z UID:nhetc/44 DESCRIPTION:Title: G iant gravitons in gauge theory\nby Sameer Murthy (King's College Londo n) as part of NHETC Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/44/ END:VEVENT BEGIN:VEVENT SUMMARY:Anna Golubeva (MIT) DTSTART:20220927T183000Z DTEND:20220927T193000Z DTSTAMP:20260422T212707Z UID:nhetc/45 DESCRIPTION:Title: O n the fundamental role of sparsity in machine learning\nby Anna Golube va (MIT) as part of NHETC Seminar\n\n\nAbstract\nSparsity and neural-netwo rk pruning have become indispensable tools in applied machine learning to alleviate the computational demands of ever larger models. While the numbe r of empirical works in this field has exploded in recent years\, bringing out a variety of pruning techniques\, finding sparse solutions at initial ization remains a challenge. Moreover\, a theoretical understanding of the very existence of sparse solutions in neural networks is lacking. In this talk\, I will discuss the most interesting open questions in this field a nd present some of our recent work combining theoretical and experimental approaches to tackle them.\n LOCATION:https://researchseminars.org/talk/nhetc/45/ END:VEVENT BEGIN:VEVENT SUMMARY:Ben Lillard (University of Oregon) DTSTART:20221004T183000Z DTEND:20221004T193000Z DTSTAMP:20260422T212707Z UID:nhetc/46 DESCRIPTION:by Ben Lillard (University of Oregon) as part of NHETC Seminar \n\n\nAbstract\nOrganic scintillators are a promising avenue for the direc t detection of sub-GeV dark matter (DM). With eV-scale excitation energies that rival the sensitivity of semiconductor targets\, they can be produce d in bulk and purified relatively inexpensively. A low-background kilogram -size scintillator target could achieve world-leading sensitivity to sub-G eV dark matter. Crystal scintillators also provide a new capability: the d ark matter scattering rate depends on the orientation of the crystal\, whi ch varies with the Earth's rotation over the course of a sidereal day (23. 93 hours). The discovery of such a signal would be a clear sign of new phy sics. While most studies of daily modulation focus on DM-electron scatteri ng\, recent results for diatomic molecules suggest that DM-nuclear scatter ing can also provide a detectable\, directional-dependent signal. In this talk I discuss both kinds of DM models\, the realistic prospects for cryst alline detectors in the near future\, and the remaining theoretical work t hat needs to be done for nuclear scattering in more complicated molecules. \n LOCATION:https://researchseminars.org/talk/nhetc/46/ END:VEVENT BEGIN:VEVENT SUMMARY:Clay Cordova (University of Chicago) DTSTART:20221011T183000Z DTEND:20221011T193000Z DTSTAMP:20260422T212707Z UID:nhetc/47 DESCRIPTION:by Clay Cordova (University of Chicago) as part of NHETC Semin ar\n\n\nAbstract\nWe elucidate the fate of classical symmetries which suff er from abelian Adler-Bell-Jackiw anomalies. Instead of being completely d estroyed\, these symmetries survive as non-invertible topological global s ymmetry defects with worldvolume anyon degrees of freedom that couple to t he bulk through a magnetic one-form global symmetry as in the fractional h all effect. These non-invertible chiral symmetries imply selection rules o n correlation functions and arise in familiar models of massless quantum e lectrodynamics and models of axions (as well as their non-abelian generali zations). When the associated bulk magnetic one-form symmetry is broken by the propagation of dynamical magnetic monopoles\, the selection rules of the non-invertible chiral symmetry defects are violated non-perturbatively . This leads to technically natural exponential hierarchies in axion poten tials and fermion masses.\n LOCATION:https://researchseminars.org/talk/nhetc/47/ END:VEVENT BEGIN:VEVENT SUMMARY:Eliezer Rabinovici (CERN) DTSTART:20221018T183000Z DTEND:20221018T193000Z DTSTAMP:20260422T212707Z UID:nhetc/48 DESCRIPTION:Title: P ersistent Spontaneous Symmetry Breaking at High Temperatures\nby Eliez er Rabinovici (CERN) as part of NHETC Seminar\n\n\nAbstract\nI will descri be the results of a series of works in which we have found systems for whi ch Spontaneous Symmetry Breaking(SSB) persists to very high temperatures. \nThe systems involve Conformal Field Theories of scalars in fractional di mensions 3F actorization and Global symmetries in holography\nby Lorenzo Di Pietro (UNITS) as part of NHETC Seminar\n\n\nAbstract\nBased on 2203.09537. In t he context of toy models of holography arising from 3d Chern-Simons theory \, I will describe an approach in which\, rather than summing over bulk ge ometries\, one gauges a one-form global symmetry of the bulk theory. This ensures that the bulk theory has no global symmetries\, and it makes the p artition function on spacetimes with boundaries coincide with that of a mo dular-invariant 2d CFT on the boundary. In particular\, on wormhole geomet ries one finds a factorized answer for the partition function.\n LOCATION:https://researchseminars.org/talk/nhetc/49/ END:VEVENT BEGIN:VEVENT SUMMARY:David Kutasov (University of Chicago) DTSTART:20221101T183000Z DTEND:20221101T193000Z DTSTAMP:20260422T212707Z UID:nhetc/50 DESCRIPTION:Title: S mall Black Holes in String Theory\nby David Kutasov (University of Chi cago) as part of NHETC Seminar\n\n\nAbstract\nI will describe some recent work on Euclidean Schwarzschild black holes in d+1 dimensional flat spacet ime\, in the limit where their Hawking temperature approaches the Hagedorn temperature. This leads to new conformal field theories\, enhanced symmet ry at the Hagedorn temperature\, and relations to earlier work on black ho les at large d. If there is time\, I will also discuss an open string anal og of this problem\, that exhibits similar phenomena.\n LOCATION:https://researchseminars.org/talk/nhetc/50/ END:VEVENT BEGIN:VEVENT SUMMARY:Matthew Bullimore (Durham University) DTSTART:20221108T193000Z DTEND:20221108T203000Z DTSTAMP:20260422T212707Z UID:nhetc/51 DESCRIPTION:Title: N on-invertible symmetry and higher representation theory\nby Matthew Bu llimore (Durham University) as part of NHETC Seminar\n\n\nAbstract\nThe pa st year has seen an explosion in constructions of non-invertible symmetrie s in quantum field theories in dimension greater than two\, such as gaugin g discrete symmetries with mixed ’t Hooft anomalies\, gauging non-normal subgroups of discrete symmetries\, higher gauging and condensations\, and duality defects. I’ll present a common framework for such constructions based on higher representation theory\, which describes higher dimensiona l analogues of topological Wilson lines. Based on joint work with Thomas B artsch\, Andrea Ferrari and Jamie Pearson.\n LOCATION:https://researchseminars.org/talk/nhetc/51/ END:VEVENT BEGIN:VEVENT SUMMARY:Shu-Heng Shao (Stony Brook University) DTSTART:20221115T193000Z DTEND:20221115T203000Z DTSTAMP:20260422T212707Z UID:nhetc/52 DESCRIPTION:Title: N on-invertible Symmetries in Nature\nby Shu-Heng Shao (Stony Brook Univ ersity) as part of NHETC Seminar\n\n\nAbstract\nI will talk about non-inve rtible global symmetries in QED and QCD\, and how the neutral pion decay r ate can be determined from matching this new global symmetry. I will then discuss a non-invertible 1-form symmetry from the anomalous Gauss law in a xion-Maxwell theory.\n LOCATION:https://researchseminars.org/talk/nhetc/52/ END:VEVENT BEGIN:VEVENT SUMMARY:Joshua Foster (MIT) DTSTART:20221122T193000Z DTEND:20221122T203000Z DTSTAMP:20260422T212707Z UID:nhetc/53 DESCRIPTION:Title: L umped Element Axion Detection at All Frequencies\nby Joshua Foster (MI T) as part of NHETC Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/53/ END:VEVENT BEGIN:VEVENT SUMMARY:Keisuke Harigaya (University of Chicago) DTSTART:20221129T193000Z DTEND:20221129T203000Z DTSTAMP:20260422T212707Z UID:nhetc/54 DESCRIPTION:Title: C osmology of Axion Rotation\nby Keisuke Harigaya (University of Chicago ) as part of NHETC Seminar\n\n\nAbstract\nWe will introduce new cosmologic al dynamics of the QCD axion\, where the axion field rotates in field spac e. Axion dark matter may be produced from the kinetic energy of the rotati on and the required axion decay constant is much below the prediction of t he conventional evolutions. The angular momentum of the rotation is transf erred into baryon asymmetry through baryon number violating interactions. We discuss the electroweak sphaleron process and some beyond-standard mode l processes and predictions on the parameters of each theory.\n LOCATION:https://researchseminars.org/talk/nhetc/54/ END:VEVENT BEGIN:VEVENT SUMMARY:Isabel Garcia Garcia (University of California - Santa Barbara) DTSTART:20221206T193000Z DTEND:20221206T203000Z DTSTAMP:20260422T212707Z UID:nhetc/55 DESCRIPTION:Title: T he Rocket Science of Bubble Walls\nby Isabel Garcia Garcia (University of California - Santa Barbara) as part of NHETC Seminar\n\n\nAbstract\nCo smological phase transitions that proceed via nucleation of bubbles are a well-motivated possibility both in minimal extensions of the Standard Mode l as well as in more general hidden sectors with their own dynamics. Such an event produces a stochastic background of gravitational radiation that could be observed by current and future observatories. That said\, our abi lity to extract any detailed information about the underlying dynamics fro m such an observation is extremely limited\, and highlights the necessity of (i) better understanding the dynamics of bubble walls in the early Univ erse\, given their impact on the high-frequency shape of the signal\, and (ii) exploring complementary probes of an observable gravitational wave ba ckground.\n\nIn this talk\, I will discuss the dynamics of expanding vacuu m bubbles in the presence of massive vectors (a.k.a. dark photons) that ga in mass across the interface -- with a special focus on the well-motivated benchmark where the dark photons furnish the dark matter. I will argue th e existence of a transient kinematic regime during which the wall behaves as an (imperfect) mirror of longitudinal -- but not transverse -- modes. M ost notably\, this leads to a new source of pressure on the expanding inte rface that can prevent the accelerated expansion of the bubble walls. Inst ead of accelerating the interface\, the difference in vacuum energy densit y across the wall goes into making a fraction of the dark photons relativi stic\, turning them into dark radiation. The corresponding value of \\Delt a N_eff is determined by the strength of the phase transition and the epoc h at which the transition takes place. Current \\Delta N_eff constraints c an rule out phase transitions with strength \\alpha \\simeq 0.1\, whereas CMB S-4 measurements will probe scenarios down to \\alpha = 0.01 for all r elevant frequencies.\n\nThis talk is based on arXiv:2212.xxxxx in collabor ation with Giacomo Koszegi and Rudin Petrossian-Byrne.\n LOCATION:https://researchseminars.org/talk/nhetc/55/ END:VEVENT BEGIN:VEVENT SUMMARY:Nikita Nekrasov (Stony Brook University) DTSTART:20220929T180000Z DTEND:20220929T190000Z DTSTAMP:20260422T212707Z UID:nhetc/56 DESCRIPTION:Title: O ne flew over the QQ-nest\nby Nikita Nekrasov (Stony Brook University) as part of NHETC Seminar\n\n\nAbstract\nI will discuss the recent progress in Omega-deformed N=2 d=4 supersymmetric quiver theories of A-type with A -type gauge group\, in the presence of various arrangements of surface def ects. According to the BPS/CFT dictionary their expectation values are giv en by the conformal blocks of some (analytically continued) CFT\, and\, at the same time\, by the matrix elements of quantum XXX spin chains. Using the qq-characters I derive (as opposed to postulate) the Q{\\tilde Q}-syst em and the Lax operators\, filling some gaps in the 30 year cycle of ideas connecting supersymmetry and integrability.\n LOCATION:https://researchseminars.org/talk/nhetc/56/ END:VEVENT BEGIN:VEVENT SUMMARY:Netta Engelhardt (MIT) DTSTART:20221110T190000Z DTEND:20221110T200000Z DTSTAMP:20260422T212707Z UID:nhetc/57 DESCRIPTION:Title: N on-Isometric Codes\, Complexity\, and the Black Hole Information Paradox\nby Netta Engelhardt (MIT) as part of NHETC Seminar\n\n\nAbstract\nThis talk focuses on recent progress on the role of computational complexity i n the black hole information paradox. I will describe quantum code models that settle the tension between two conflicting calculations of the entrop y of Hawking radiation within semiclassical gravity: the standard “Hawki ng” calculation and the quantum extremal surface calculation. The critic al aspect of the construction involves a complexity bound on the validity of effective field theory\, and I will discuss applications of this from t he geometric perspective of holography as well as computationally bounded quantum learning.\n LOCATION:https://researchseminars.org/talk/nhetc/57/ END:VEVENT BEGIN:VEVENT SUMMARY:Seminar is Cancelled: Gabriel Wong (Harvard CMSA) DTSTART:20221201T190000Z DTEND:20221201T200000Z DTSTAMP:20260422T212707Z UID:nhetc/58 DESCRIPTION:Title: S eminar is Cancelled: Generalized entropy in topological string theory \nby Seminar is Cancelled: Gabriel Wong (Harvard CMSA) as part of NHETC S eminar\n\n\nAbstract\nSeminar is Cancelled: The holographic entanglement entropy formula identifies the generalized entropy of the bulk AdS spaceti me with the entanglement entropy of the boundary CFT. However the bulk mic rostate interpretation of the generalized entropy remains poorly understoo d. Progress along this direction requires a definition of Hilbert space fa ctorization and entanglement entropy in the bulk closed string theory. A s a toy model for AdS/CFT\, we study the entanglement entropy of closed st rings in the topological A model\, which enjoys a gauge-string duality. We define a notion of generalized entropy for closed strings on the resolv ed conifold using the replica trick. As in AdS/CFT\, we find this is dua l to (defect) entanglement entropy in the dual Chern Simons gauge theory. Our main result is a bulk microstate interpretation of the generalized e ntropy for closed strings as the entanglement entropy of open strings endi ng on ``entanglement branes" . These branes are interpreted as entangl ement edge modes\, which transform under a quantum group symmetry. We rel ate these entanglement branes to the D branes of the A model topological s tring.\n LOCATION:https://researchseminars.org/talk/nhetc/58/ END:VEVENT BEGIN:VEVENT SUMMARY:Sunil Mukhi (IISER Pune) DTSTART:20221208T190000Z DTEND:20221208T200000Z DTSTAMP:20260422T212707Z UID:nhetc/59 DESCRIPTION:Title: C lassification of Unitary RCFTs with Two Primaries and c < 25\nby Sunil Mukhi (IISER Pune) as part of NHETC Seminar\n\n\nAbstract\nI will present a classification of all unitary\, rational\nconformal field theories with two primaries\, central charge c < 25\,\nand arbitrary Wronskian index. (Work in collaboration with Brandon\nRayhaun\, arXiv: 2208.05486). These a re shown to be either certain\nlevel-1 WZW models or cosets of meromorphic theories by such models.\nBy leveraging the existing classification of m eromorphic CFTs of\ncentral charge c ≤ 24\, all the relevant cosets are enumerated and\ntheir characters computed. This leads to 123 theories\, mo st of which\nare new. It will be emphasised that this is a classification of RCFTs\nand not just consistent characters.This work makes use of early\ nresults in the classification of RCFT using modular linear\ndifferential equations and cosets\, the relevant background will be\nreviewed.\n LOCATION:https://researchseminars.org/talk/nhetc/59/ END:VEVENT BEGIN:VEVENT SUMMARY:Petr Hořava (UC Berkeley) DTSTART:20221213T193000Z DTEND:20221213T203000Z DTSTAMP:20260422T212707Z UID:nhetc/60 DESCRIPTION:Title: T opological Quantum Gravity of the Ricci Flow\nby Petr Hořava (UC Berk eley) as part of NHETC Seminar\n\n\nAbstract\nUsing the techniques of coho mological quantum field theories\, we construct a topological nonrelativis tic quantum gravity\, designed around the mathematical theory of the Ricci flow on Riemannian manifolds\, as used by Perelman in his proof of the Po incare conjecture and Thurston's geometrization theorem. This quantum fie ld theory brings together three\, previously not directly related areas: Topological field theory of the cohomological type\, nonrelativistic quant um gravity of the Lifshitz type\, and the mathematics of geometric flows o n manifolds. We identify the precise theory whose path integral localizes to the solutions of the Perelman's version of the Ricci flow equations\, and identify various features of Perelman's construction in the physics la nguage\, such as Perelman's entropy functional (which plays the role of ou r superpotential)\, Perelman's dilaton field (which maps to the lapse func tion of nonrelativistic gravity)\, and others. With this embedding of Per elman's Ricci flow to topological quantum gravity\, many intriguing result s about the structure of the flow accumulated on the mathematical side in the past two decades can now be imported into the physical picture in the path integral formulation of quantum gravity.\n LOCATION:https://researchseminars.org/talk/nhetc/60/ END:VEVENT BEGIN:VEVENT SUMMARY:Ingo Runkel (Universität Hamburg) DTSTART:20221220T193000Z DTEND:20221220T203000Z DTSTAMP:20260422T212707Z UID:nhetc/61 DESCRIPTION:Title: T opological symmetries and their gaugings in 2dCFT and 3dTFT\nby Ingo R unkel (Universität Hamburg) as part of NHETC Seminar\n\n\nAbstract\nThe s tudy of topological defects in quantum field theory as seen a wealth of ac tivity recently leading to many interesting insights\, for example the exp licit realization of non-invertible topological defects in higher dimensio nal QFTs via the gauging of higher form symmetries\, or the description of the higher algebraic structures inherent in these topological defects. \n \nIn this talk\, I would like to focus on low-dimensional examples\, where such defects and their properties have been investigated for some time al ready. I would like to exhibit some of the properties of topological defec ts in two-dimensional conformal field theory and in three-dimensional topo logical field theory\, and show some of the structural insights into 2dCFT and 3dTFT one can gain with the help of defects. In this way\, the well-u nderstood low-dimensional case might serves as a source of ideas and as a test-case for higher dimensional constructions.\n LOCATION:https://researchseminars.org/talk/nhetc/61/ END:VEVENT BEGIN:VEVENT SUMMARY:David Tong (University of Cambridge) DTSTART:20230124T193000Z DTEND:20230124T203000Z DTSTAMP:20260422T212707Z UID:nhetc/62 DESCRIPTION:Title: A Chern-Simons Theory for the North Atlantic Ocean\nby David Tong (Univ ersity of Cambridge) as part of NHETC Seminar\n\n\nAbstract\nIn some ways the ocean acts like a topological insulator. There are chiral edge modes\, localised at the coast\, that go clockwise in the Northern hemisphere and anti-clockwise in the Southern hemisphere. I’ll describe these properti es and explain how they can be understood in terms of something more famil iar to high energy physicists. I’ll show that the equations that govern the long-time dynamics of the ocean can be recast as a Maxwell-Chern-Simon s theory.\n LOCATION:https://researchseminars.org/talk/nhetc/62/ END:VEVENT BEGIN:VEVENT SUMMARY:Nathan Seiberg (Institute for Advanced Study) DTSTART:20230131T193000Z DTEND:20230131T203000Z DTSTAMP:20260422T212707Z UID:nhetc/63 DESCRIPTION:Title: S ymmetries and Anomalies in the Continuum and on the Lattice\nby Nathan Seiberg (Institute for Advanced Study) as part of NHETC Seminar\n\n\nAbst ract\nBased on joint work with Meng Cheng (arXiv:2211.12543)\, we will dis cuss some aspects of global symmetries and their ‘t Hooft anomalies.\n\n We will define a notion of an emanant global symmetry. It is not a symmetr y of the UV theory\, but unlike emergent (accidental) symmetries\, it is n ot violated by any relevant or irrelevant operators in the IR theory.\n\nW e will present lattice models with anomalous internal symmetries and see h ow the anomalies are diagnosed on the lattice using topological defects.\n \nWe will also discuss lattice models with anomalous lattice translation a nd relate them to an anomalous emanant symmetry in the IR theory. This wil l connect our discussion to the well-known Lieb-Schultz-Mattis theorem and to filling constraints like Luttinger theorem.\n LOCATION:https://researchseminars.org/talk/nhetc/63/ END:VEVENT BEGIN:VEVENT SUMMARY:Johanna Erdmenger (Julius Maximilian University Würzburg) DTSTART:20230425T183000Z DTEND:20230425T193000Z DTSTAMP:20260422T212707Z UID:nhetc/64 DESCRIPTION:Title: D iscrete Holography\nby Johanna Erdmenger (Julius Maximilian University Würzburg) as part of NHETC Seminar\n\n\nAbstract\nI will review recent p rogress towards establishing a holographic duality for discrete spaces inv olving a regular tiling of hyperbolic space. In particular\, I will presen t a recent example where an aperiodic XXZ spin chain is obtained naturally by extrapolating the bulk tiling to its boundary. The properties of this model are studied using RG techniques\, which provide a tensor network con struction for its ground state. We calculate and compare the entanglement entropy both at the boundary and in the bulk. I will comment on the symmet ries of the construction and on the next steps towards obtaining a full dy namical duality of discrete systems. In particular\, this may be useful fo r going beyond the large N limit on the gravity side.\n\n Based on arXiv 2205.05693\, 2205.05081 and 2212.11292.\n LOCATION:https://researchseminars.org/talk/nhetc/64/ END:VEVENT BEGIN:VEVENT SUMMARY:Fiona Burnell (University of Minnesota) DTSTART:20230523T183000Z DTEND:20230523T193000Z DTSTAMP:20260422T212707Z UID:nhetc/65 DESCRIPTION:Title: A bulk-boundary correspondence for non-invertible symmetries\nby Fiona Burnell (University of Minnesota) as part of NHETC Seminar\n\n\nAbstract\n The notion that symmetry in a d-dimensional QFT is naturally described by placing this QFT at the boundary of a d+1 dimensional TQFT has been very p owerful in understanding generalized symmetry actions\, particularly for n on-invertible symmetries. I discuss a concrete family of models in 2 spa tial dimensions\, which can be viewed on the one hand as Hamiltonian model s describing bulk topological orders\, and on the other hand (when the bul k is in its ground state) as bulk TQFT’s describing a symmetry action at the boundary. I will describe how to add additional symmetry by “shadi ng” and “completing” the bulk models. This leads to models which r ealize interesting symmetries in an onsite manner. Specifically\, in the bulk\, these shaded models realize symmetries that permute the anyons in t he underlying TQFT. At the boundary\, these symmetries can take the form of generalized Kramers-Wannier dualities in the boundary spin model. I w ill illustrate how this works in a few simple examples.\n LOCATION:https://researchseminars.org/talk/nhetc/65/ END:VEVENT BEGIN:VEVENT SUMMARY:Mihoko Nojiri (KEK Theory Center) DTSTART:20230202T173000Z DTEND:20230202T183000Z DTSTAMP:20260422T212707Z UID:nhetc/67 DESCRIPTION:Title: F uture electron beam dump experiments\nby Mihoko Nojiri (KEK Theory Cen ter) as part of NHETC Seminar\n\n\nAbstract\nA beam dump experiment can be seamlessly added to the proposed International Linear Collider (ILC) prog ram because the high-energy electron beam should be dumped after the colli sion point. The ILC beam dump experiment will provide an excellent opportu nity to search for new long-lived particles(LLP). An LPP couple to a photo n\, such as axion-like particles\, can be searched there. Furthermore\, th e photon and electron in EM shower hit nuclei and produce hadrons. As a mo tivated physics case\, we study the projected sensitivity of heavy neutral leptons at the ILC beam dump experiment. The study shows\,somewhat counte r-intuitively\, that the reach would be significantly extended in mass and coupling\, even compared with the other proposed searches.　I also intro duce proposed ALP studies using KEK linac\; currently\, test beam studies are starting.\n LOCATION:https://researchseminars.org/talk/nhetc/67/ END:VEVENT BEGIN:VEVENT SUMMARY:Malte Buschmann (Princeton University) DTSTART:20230207T193000Z DTEND:20230207T203000Z DTSTAMP:20260422T212707Z UID:nhetc/68 DESCRIPTION:Title: T he post-inflationary axion\nby Malte Buschmann (Princeton University) as part of NHETC Seminar\n\n\nAbstract\nThe axion is a hypothetical partic le that solves the strong CP problem of quantum chromodynamics (QCD) while simultaneously being an excellent dark matter candidate. If the axion is generated after inflation\, many unique objects arise from the theory\, fr om axion strings and domain walls to oscillons\, miniclusters\, and axion stars. The result is many potentially observable signatures\, whether in t he CMB\, the gravitational wave background or in neutron star data. More i mportantly\, this scenario is entirely deterministic\, allowing precise pr edictions through numerical simulations. In this talk\, I will go through the cosmological history of such a post-inflationary axion to put the vari ous phenomena into context and highlight the remaining open questions.\n LOCATION:https://researchseminars.org/talk/nhetc/68/ END:VEVENT BEGIN:VEVENT SUMMARY:Edward Witten (Institute for Advanced Study) DTSTART:20230221T193000Z DTEND:20230221T203000Z DTSTAMP:20260422T212707Z UID:nhetc/69 DESCRIPTION:Title: T he Timelike Tube Theorem\nby Edward Witten (Institute for Advanced Stu dy) as part of NHETC Seminar\n\n\nAbstract\nI will explain the ideas invol ved in the timelike tube theorem\, which says that the algebra of quantum fields along the worldline of an observer is the same as (roughly) the a lgebra of quantum fields in a spacetime region that is causally accessible to the observer. The earliest version was proved by Borchers and Araki in the 1960's.\n LOCATION:https://researchseminars.org/talk/nhetc/69/ END:VEVENT BEGIN:VEVENT SUMMARY:Manuel Szewc (University of Cincinnati) DTSTART:20230307T193000Z DTEND:20230307T203000Z DTSTAMP:20260422T212707Z UID:nhetc/71 DESCRIPTION:Title: N ull Hypothesis Test for Anomaly Detection\nby Manuel Szewc (University of Cincinnati) as part of NHETC Seminar\n\n\nAbstract\nIn this talk we pr esent a hypothesis test designed to exclude the background-only hypothesis for Anomaly detection searchs. Extending Classification Without Labels\, we show that by testing for statistical independence of the two discrimina ting dataset regions\, we are able exclude the background-only hypothesis without relying on fixed anomaly score cuts or extrapolations of backgroun d estimates between regions. The method relies on the assumption of condit ional independence of anomaly score features and dataset regions\, which c an be ensured using existing decorrelation techniques. As a benchmark exam ple\, we consider the LHC Olympics dataset where we show that mutual infor mation represents a suitable test for statistical independence and our met hod exhibits excellent and robust performance at different signal fraction s even in presence of realistic feature correlations.\n LOCATION:https://researchseminars.org/talk/nhetc/71/ END:VEVENT BEGIN:VEVENT SUMMARY:Gleb Kotousov (Leibniz University Hannover) DTSTART:20230309T190000Z DTEND:20230309T200000Z DTSTAMP:20260422T212707Z UID:nhetc/72 DESCRIPTION:Title: 2 D black hole sigma models from an integrable spin chain\nby Gleb Kotou sov (Leibniz University Hannover) as part of NHETC Seminar\n\n\nAbstract\n The staggered six-vertex model is a 1D critical integrable spin chain that exhibits a variety of interesting universal behaviour. This includes a re gime where the spectrum of critical exponents contains a continuous compon ent and matches that of the Euclidean version of the 2D black hole non-lin ear sigma model. In this talk the relation between the scaling limit of th e vertex model and the Euclidean/Lorentzian black hole sigma models is dis cussed. Some new results on the density of states of the continuous spectr um for the Euclidean black hole CFT are presented\, which were obtained vi a an analysis of the lattice system. The talk is largely based on the work 2010.10603.\n LOCATION:https://researchseminars.org/talk/nhetc/72/ END:VEVENT BEGIN:VEVENT SUMMARY:Kevin Croker (University of Hawaii) DTSTART:20230314T183000Z DTEND:20230314T193000Z DTSTAMP:20260422T212707Z UID:nhetc/73 DESCRIPTION:by Kevin Croker (University of Hawaii) as part of NHETC Semina r\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/73/ END:VEVENT BEGIN:VEVENT SUMMARY:David Dunsky (NYU) DTSTART:20230321T183000Z DTEND:20230321T193000Z DTSTAMP:20260422T212707Z UID:nhetc/74 DESCRIPTION:Title: A Heavy QCD Axion and the Mirror World\nby David Dunsky (NYU) as part o f NHETC Seminar\n\n\nAbstract\nIn this talk\, I will discuss the mirror wo rld with dark matter arising from the thermal freeze-out of the lightest\, stable mirror particle -- the mirror electron. The dark matter abundance is achieved for mirror electrons of mass 225 GeV\, fixing the mirror elect roweak scale near 10^8 GeV. This highly predictive scenario is realized by an axion that acts as a portal between the two sectors through its coupli ng to the QCD and mirror QCD sectors. The axion is more massive than the s tandard QCD axion due to additional contributions from mirror strong dynam ics. Still\, the strong CP problem is solved by this "heavy" axion due to the alignment of the QCD and mirror QCD potentials. Mirror entropy is tran sferred into the Standard Model sector via the axion portal\, which allevi ates overproduction of dark radiation from mirror glueball decays. I will discuss four signals from this model: (1) primordial gravitational waves f rom the first-order mirror QCD phase transition occurring at a temperature near 35 GeV\, (2) effects on large-scale structure from dark matter self- interactions from mirror QED\, (3) dark radiation affecting the cosmic mic rowave background\, and (4) the rare kaon decay\, (kaon -> pion +axion). T he first two signals do not depend on any fundamental free parameters of t he theory while the latter two depend on a single free parameter\, the axi on decay constant.\n LOCATION:https://researchseminars.org/talk/nhetc/74/ END:VEVENT BEGIN:VEVENT SUMMARY:Annika Peter (Harvard) DTSTART:20230404T183000Z DTEND:20230404T193000Z DTSTAMP:20260422T212707Z UID:nhetc/75 DESCRIPTION:by Annika Peter (Harvard) as part of NHETC Seminar\n\nAbstract : TBA\n LOCATION:https://researchseminars.org/talk/nhetc/75/ END:VEVENT BEGIN:VEVENT SUMMARY:Seth Koren (Chicago) DTSTART:20230502T183000Z DTEND:20230502T193000Z DTSTAMP:20260422T212707Z UID:nhetc/76 DESCRIPTION:Title: P utting Generalized Symmetries to Work for Particle Physics\nby Seth Ko ren (Chicago) as part of NHETC Seminar\n\n\nAbstract\nOver the past decade \, field theorists have developed a novel framework for thinking about glo bal symmetries which has enormously generalized our understanding thereof. Quite recently\, my collaborators and I have established positively that past being a useful formal tool\, such generalized symmetries are indeed p resent in models that we care about as particle physicists---and furthermo re understanding them can lead to new insights into these models. As a fir st example\, the Standard Model itself has a 'higher-group' symmetry inter twining flavor and hypercharge\, and I will discuss how this symmetry cont rols the structure of unification. Going Beyond\, I will show that the ide ntification of a 'non-invertible' symmetry of Z' models of L_µ - L_τ rev eals the existence of simple UV completions thereof where the scale of neu trino masses is exponentially suppressed from that of charged leptons.\n LOCATION:https://researchseminars.org/talk/nhetc/76/ END:VEVENT BEGIN:VEVENT SUMMARY:Mariel Pettee (Lawrence Berkeley National Laboratory / Flatiron In stitute Center for Computational Astrophysics) DTSTART:20230511T163000Z DTEND:20230511T183000Z DTSTAMP:20260422T212707Z UID:nhetc/77 DESCRIPTION:Title: W eakly-Supervised Anomaly Detection in the Milky Way\nby Mariel Pettee (Lawrence Berkeley National Laboratory / Flatiron Institute Center for Com putational Astrophysics) as part of NHETC Seminar\n\n\nAbstract\nClassific ation Without Labels (CWoLa) is a weakly-supervised anomaly detection tech nique that leverages neural networks to identify cold stellar streams with in the more than one billion Milky Way stars observed by the Gaia satellit e. The CWoLa methodology operates without the use of labeled streams or kn owledge of astrophysical principles. Instead\, it uses a classifier to dis tinguish between mixed samples for which the proportions of signal and bac kground samples are unknown. This computationally lightweight strategy is able to detect both simulated streams and the known stream GD-1 in data. O riginally designed for high-energy collider physics\, this technique may h ave broad applicability within astrophysics as well as other domains inter ested in identifying localized anomalies.\n LOCATION:https://researchseminars.org/talk/nhetc/77/ END:VEVENT BEGIN:VEVENT SUMMARY:Jonathan Heckman (University of Pennsylvania) DTSTART:20230228T193000Z DTEND:20230228T203000Z DTSTAMP:20260422T212707Z UID:nhetc/78 DESCRIPTION:Title: I IB Determined\nby Jonathan Heckman (University of Pennsylvania) as par t of NHETC Seminar\n\n\nAbstract\nWe use the Swampland Cobordism Conjectur e recently proposed by McNamara and Vafa to study the spectrum of objects in type IIB string theory. A famous feature of type IIB string theory (as well as many quantum systems) is that it enjoys a non-abelian duality grou p. By computing the relevant cobordism groups\, we show that the cobordism conjecture successfully reconstructs many known supersymmetric objects\, and also predicts the existence of a new non-supersymmetric "reflection 7- brane\," the properties of which we describe. Based on joint work with Deb ray\, Dierigl\, Montero and Torres.\n LOCATION:https://researchseminars.org/talk/nhetc/78/ END:VEVENT BEGIN:VEVENT SUMMARY:Lina Necib (MIT) DTSTART:20230905T183000Z DTEND:20230905T193000Z DTSTAMP:20260422T212707Z UID:nhetc/79 DESCRIPTION:Title: ( Machine) Learning of Dark Matter\nby Lina Necib (MIT) as part of NHETC Seminar\n\n\nAbstract\nIn this talk\, I explore the impact of stellar kin ematics on understanding the particle nature of Dark Matter\, overviewing the correlations between stellar and Dark Matter phase space distributions in three separate locations: the solar neighborhood\, the Galactic center \, and dwarf galaxies. I will focus on the use of machine learning techniq ues applied to data from the Gaia mission to disentangle the local kinemat ics substructures\, and the use of simulations to study the correlations b etween stars and Dark Matter. I will end by relating these empirical measu rements to Dark Matter detection experiments.\n LOCATION:https://researchseminars.org/talk/nhetc/79/ END:VEVENT BEGIN:VEVENT SUMMARY:Katherine Fraser (Harvard) DTSTART:20230418T183000Z DTEND:20230418T193000Z DTSTAMP:20260422T212707Z UID:nhetc/80 DESCRIPTION:by Katherine Fraser (Harvard) as part of NHETC Seminar\n\nAbst ract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/80/ END:VEVENT BEGIN:VEVENT SUMMARY:Stefano Negro (NYU) DTSTART:20230328T183000Z DTEND:20230328T193000Z DTSTAMP:20260422T212707Z UID:nhetc/81 DESCRIPTION:Title: T he relevance of being irrelevant\nby Stefano Negro (NYU) as part of NH ETC Seminar\n\n\nAbstract\nIn the last few years\, 2-dimensional Quantum F ield Theories deformed by irrelevant operators have been receiving a stead ily growing amount of attention from the Theoretical Physics community. Th e main reason for this interest lies in the unexpected amount of control t hat it is possible to exert on the high-energy properties of a vast family of these deformations. These\, often referred to as “solvable irrelevan t deformations”\, in spite of being by standard arguments non-renormalis able\, allow us to follow the irrelevant flow all the way to the UV and to obtain exact results on the high-energy physics. The latter are remarkabl e: the finite-size density of states grows exponentially at high energies\ , in a Hagedorn fashion reminiscent of String Theories. These deformed the ories are not compatible with Wilson’s paradigm of local QFTs and cannot be considered conventional UV-complete theories. However\, thanks to thei r robust features\, they represent a sensible extension of the Wilsonian n otion of a local QFT.\n\nI will recall the main features of the TTbar defo rmations\, the poster child of solvable irrelevant deformations\, in an in troductory manner. If time permits I will then describe the more recent de velopments for a vast class of irrelevant deformations of 2D Integrable QF Ts\, paying particular attention to their interpretation as factorised sca ttering theories. This perspective reveals the importance of these theorie s in the task undertaken by the Bootstrap community of mapping out the spa ce of consistent scattering matrices.\n LOCATION:https://researchseminars.org/talk/nhetc/81/ END:VEVENT BEGIN:VEVENT SUMMARY:Thomas Banks (Rutgers) DTSTART:20230323T183000Z DTEND:20230323T193000Z DTSTAMP:20260422T212707Z UID:nhetc/82 DESCRIPTION:Title: T he Density Matrix of a Causal Diamond\nby Thomas Banks (Rutgers) as pa rt of NHETC Seminar\n\n\nAbstract\nI will review and reinterpret a number of papers from the 1990s\, which indicate that the operator algebra of a c ausal diamond in models of quantum gravity is finite dimensional and that the modular Hamiltonian of the "empty diamond" state has an expectation va lue and fluctuations determined by geometrical properties of the diamond. These universal formulae depend on a view of Einstein's equations as the hydrodynamic equations of the area law for diamond entropy\, which means t hat they are valid beyond any "semi-classical" approximation. A model of quantum gravity consists of finding a quantum system whose hydrodynamics i s consistent with a given solution of Einstein's equations. I will quickl y review many papers and attendees are encouraged to read them before the talk. (List will follow). Among the many implications of these papers is that quantum field theory cannot account for most of the entropy in a cau sal diamond\, and that the cosmological constant should not be thought of as an energy density. \n\nReferences:\n\n 1. A. G. Cohen\, D. B. Kaplan and A. E. Nelson\, Phys. Rev. Lett. 82\, 4971-4974 (1999)doi:10.1103/Phys RevLett.82.4971 [arXiv:hep-th/9803132 [hep-th]].\n\n 2. T. Banks and P. Draper\, Phys. Rev. D 101\, no.12\, 126010 (2020) doi:10.1103/PhysRevD.10 1.126010[arXiv:1911.05778 [hep-th]].\n\n 3. N. Blinov and P. Draper\, P hys. Rev. D 104\, no.7\, 076024 (2021) doi:10.1103/PhysRevD.104.076024[arX iv:2107.03530 [hep-ph]].\n\n 4. R. D. Sorkin\, [arXiv:1402.3589 [gr-qc] ].\n\n 5. M. Srednicki\, Phys. Rev. Lett. 71\, 666-669 (1993) doi:10.11 03/PhysRevLett.71.666[arXiv:hep-th/9303048 [hep-th]].\n\n 6. C. G. Call an\, Jr. and F. Wilczek\, Phys. Lett. B 333\, 55-61 (1994) doi:10.1016/037 0-2693(94)91007-3 [arXiv:hep-th/9401072 [hep-th]].\n\n 7. L. Susskind a nd J. Uglum\, Phys. Rev. D 50\, 2700-2711 (1994) doi:10.1103/PhysRevD.50.2 700[arXiv:hep-th/9401070 [hep-th]].\n\n 8. T. Jacobson\, [arXiv:gr-qc/9 404039 [gr-qc]].\n\n 9. T. Jacobson\, Phys. Rev. Lett. 75\, 1260-1263 ( 1995) doi:10.1103/PhysRevLett.75.1260[arXiv:gr-qc/9504004 [gr-qc]].\n\n 10. W. Fischler and L. Susskind\, [arXiv:hep-th/9806039 [hep-th]].\n\n 11. R. Bousso\, Class. Quant. Grav. 17\, 997-1005 (2000) doi:10.1088/0264 -9381/17/5/309[arXiv:hep-th/9911002 [hep-th]]. ETC.\n\n 12. H. L. Verli nde and E. P. Verlinde\, Nucl. Phys. B 371\, 246-268 (1992) doi:10.1016/05 50-3213(92)90236-5 [arXiv:hep-th/9110017 [hep-th]].\n\n 13. S. Carlip\, Phys. Rev. Lett. 82\, 2828-2831 (1999) doi:10.1103/PhysRevLett.82.2828[ar Xiv:hep-th/9812013 [hep-th]]. ETC.\n\n 14. S. N. Solodukhin\, Phys. Let t. B 454\, 213-222 (1999) doi:10.1016/S0370-2693(99)00398-6[arXiv:hep-th/9 812056 [hep-th]]. \n\n 15. T. Banks and K. M. Zurek\, Phys. Rev. D 104 \, no.12\, 126026 (2021) doi:10.1103/PhysRevD.104.126026[arXiv:2108.04806 [hep-th]].\n LOCATION:https://researchseminars.org/talk/nhetc/82/ END:VEVENT BEGIN:VEVENT SUMMARY:Thomas Banks (Rutgers) DTSTART:20230330T183000Z DTEND:20230330T193000Z DTSTAMP:20260422T212707Z UID:nhetc/83 DESCRIPTION:Title: T he Density Matrix of a Causal Diamond\nby Thomas Banks (Rutgers) as pa rt of NHETC Seminar\n\n\nAbstract\nI will review and reinterpret a number of papers from the 1990s\, which indicate that the operator algebra of a c ausal diamond in models of quantum gravity is finite dimensional and that the modular Hamiltonian of the "empty diamond" state has an expectation va lue and fluctuations determined by geometrical properties of the diamond. These universal formulae depend on a view of Einstein's equations as the hydrodynamic equations of the area law for diamond entropy\, which means t hat they are valid beyond any "semi-classical" approximation. A model of quantum gravity consists of finding a quantum system whose hydrodynamics i s consistent with a given solution of Einstein's equations. I will quickl y review many papers and attendees are encouraged to read them before the talk. (List will follow). Among the many implications of these papers is that quantum field theory cannot account for most of the entropy in a cau sal diamond\, and that the cosmological constant should not be thought of as an energy density. \n\nReferences:\n\n 1. A. G. Cohen\, D. B. Kaplan and A. E. Nelson\, Phys. Rev. Lett. 82\, 4971-4974 (1999)doi:10.1103/Phys RevLett.82.4971 [arXiv:hep-th/9803132 [hep-th]].\n\n 2. T. Banks and P. Draper\, Phys. Rev. D 101\, no.12\, 126010 (2020) doi:10.1103/PhysRevD.10 1.126010[arXiv:1911.05778 [hep-th]].\n\n 3. N. Blinov and P. Draper\, P hys. Rev. D 104\, no.7\, 076024 (2021) doi:10.1103/PhysRevD.104.076024[arX iv:2107.03530 [hep-ph]].\n\n 4. R. D. Sorkin\, [arXiv:1402.3589 [gr-qc] ].\n\n 5. M. Srednicki\, Phys. Rev. Lett. 71\, 666-669 (1993) doi:10.11 03/PhysRevLett.71.666[arXiv:hep-th/9303048 [hep-th]].\n\n 6. C. G. Call an\, Jr. and F. Wilczek\, Phys. Lett. B 333\, 55-61 (1994) doi:10.1016/037 0-2693(94)91007-3 [arXiv:hep-th/9401072 [hep-th]].\n\n 7. L. Susskind a nd J. Uglum\, Phys. Rev. D 50\, 2700-2711 (1994) doi:10.1103/PhysRevD.50.2 700[arXiv:hep-th/9401070 [hep-th]].\n\n 8. T. Jacobson\, [arXiv:gr-qc/9 404039 [gr-qc]].\n\n 9. T. Jacobson\, Phys. Rev. Lett. 75\, 1260-1263 ( 1995) doi:10.1103/PhysRevLett.75.1260[arXiv:gr-qc/9504004 [gr-qc]].\n\n 10. W. Fischler and L. Susskind\, [arXiv:hep-th/9806039 [hep-th]].\n\n 11. R. Bousso\, Class. Quant. Grav. 17\, 997-1005 (2000) doi:10.1088/0264 -9381/17/5/309[arXiv:hep-th/9911002 [hep-th]]. ETC.\n\n 12. H. L. Verli nde and E. P. Verlinde\, Nucl. Phys. B 371\, 246-268 (1992) doi:10.1016/05 50-3213(92)90236-5 [arXiv:hep-th/9110017 [hep-th]].\n\n 13. S. Carlip\, Phys. Rev. Lett. 82\, 2828-2831 (1999) doi:10.1103/PhysRevLett.82.2828[ar Xiv:hep-th/9812013 [hep-th]]. ETC.\n\n 14. S. N. Solodukhin\, Phys. Let t. B 454\, 213-222 (1999) doi:10.1016/S0370-2693(99)00398-6[arXiv:hep-th/9 812056 [hep-th]]. \n\n 15. T. Banks and K. M. Zurek\, Phys. Rev. D 104 \, no.12\, 126026 (2021) doi:10.1103/PhysRevD.104.126026[arXiv:2108.04806 [hep-th]].\n LOCATION:https://researchseminars.org/talk/nhetc/83/ END:VEVENT BEGIN:VEVENT SUMMARY:Gabriel Wong (Harvard CMSA) DTSTART:20230504T180000Z DTEND:20230504T190000Z DTSTAMP:20260422T212707Z UID:nhetc/84 DESCRIPTION:Title: G eneralized entropy in topological string theory\nby Gabriel Wong (Harv ard CMSA) as part of NHETC Seminar\n\n\nAbstract\nThe holographic entangle ment entropy formula identifies the generalized entropy of the bulk AdS sp acetime with the entanglement entropy of the boundary CFT. However the bul k microstate interpretation of the generalized entropy remains poorly unde rstood. Progress along this direction requires a definition of Hilbert sp ace factorization and entanglement entropy in the bulk closed string theor y. As a toy model for AdS/CFT\, we study the entanglement entropy of clos ed strings in the topological A model\, which enjoys a gauge-string dualit y. We define a notion of generalized entropy for closed strings on the re solved conifold using the replica trick. As in AdS/CFT\, we find this is dual to (defect) entanglement entropy in the dual Chern Simons gauge theo ry. Our main result is a bulk microstate interpretation of the generaliz ed entropy for closed strings as the entanglement entropy of open strings ending on ``entanglement branes" . These branes are interpreted as entangl ement edge modes\, which transform under a quantum group symmetry. We rel ate these entanglement branes to the Dbranes of the A model topological st ring.\n LOCATION:https://researchseminars.org/talk/nhetc/84/ END:VEVENT BEGIN:VEVENT SUMMARY:Thomas Banks (Rutgers) DTSTART:20230427T183000Z DTEND:20230427T193000Z DTSTAMP:20260422T212707Z UID:nhetc/85 DESCRIPTION:Title: T he Density Matrix Of A Causal Diamond\nby Thomas Banks (Rutgers) as pa rt of NHETC Seminar\n\n\nAbstract\nI will review and reinterpret a number of papers from the 1990s\, which indicate that the operator algebra of a c ausal diamond in models of quantum gravity is finite dimensional and that the modular Hamiltonian of the "empty diamond" state has an expectation va lue and fluctuations determined by geometrical properties of the diamond. These universal formulae depend on a view of Einstein's equations as the hydrodynamic equations of the area law for diamond entropy\, which means t hat they are valid beyond any "semi-classical" approximation. A model of quantum gravity consists of finding a quantum system whose hydrodynamics i s consistent with a given solution of Einstein's equations. I will quickl y review many papers and attendees are encouraged to read them before the talk. (List will follow). Among the many implications of these papers is that quantum field theory cannot account for most of the entropy in a cau sal diamond\, and that the cosmological constant should not be thought of as an energy density. \n\nReferences:\n\n 1. A. G. Cohen\, D. B. Kaplan and A. E. Nelson\, Phys. Rev. Lett. 82\, 4971-4974 (1999)doi:10.1103/Phys RevLett.82.4971 [arXiv:hep-th/9803132 [hep-th]].\n\n 2. T. Banks and P. Draper\, Phys. Rev. D 101\, no.12\, 126010 (2020) doi:10.1103/PhysRevD.10 1.126010[arXiv:1911.05778 [hep-th]].\n\n 3. N. Blinov and P. Draper\, P hys. Rev. D 104\, no.7\, 076024 (2021) doi:10.1103/PhysRevD.104.076024[arX iv:2107.03530 [hep-ph]].\n\n 4. R. D. Sorkin\, [arXiv:1402.3589 [gr-qc] ].\n\n 5. M. Srednicki\, Phys. Rev. Lett. 71\, 666-669 (1993) doi:10.11 03/PhysRevLett.71.666[arXiv:hep-th/9303048 [hep-th]].\n\n 6. C. G. Call an\, Jr. and F. Wilczek\, Phys. Lett. B 333\, 55-61 (1994) doi:10.1016/037 0-2693(94)91007-3 [arXiv:hep-th/9401072 [hep-th]].\n\n 7. L. Susskind a nd J. Uglum\, Phys. Rev. D 50\, 2700-2711 (1994) doi:10.1103/PhysRevD.50.2 700[arXiv:hep-th/9401070 [hep-th]].\n\n 8. T. Jacobson\, [arXiv:gr-qc/9 404039 [gr-qc]].\n\n 9. T. Jacobson\, Phys. Rev. Lett. 75\, 1260-1263 ( 1995) doi:10.1103/PhysRevLett.75.1260[arXiv:gr-qc/9504004 [gr-qc]].\n\n 10. W. Fischler and L. Susskind\, [arXiv:hep-th/9806039 [hep-th]].\n\n 11. R. Bousso\, Class. Quant. Grav. 17\, 997-1005 (2000) doi:10.1088/0264 -9381/17/5/309[arXiv:hep-th/9911002 [hep-th]]. ETC.\n\n 12. H. L. Verli nde and E. P. Verlinde\, Nucl. Phys. B 371\, 246-268 (1992) doi:10.1016/05 50-3213(92)90236-5 [arXiv:hep-th/9110017 [hep-th]].\n\n 13. S. Carlip\, Phys. Rev. Lett. 82\, 2828-2831 (1999) doi:10.1103/PhysRevLett.82.2828[ar Xiv:hep-th/9812013 [hep-th]]. ETC.\n\n 14. S. N. Solodukhin\, Phys. Let t. B 454\, 213-222 (1999) doi:10.1016/S0370-2693(99)00398-6[arXiv:hep-th/9 812056 [hep-th]]. \n\n 15. T. Banks and K. M. Zurek\, Phys. Rev. D 104 \, no.12\, 126026 (2021) doi:10.1103/PhysRevD.104.126026[arXiv:2108.04806 [hep-th]].\n LOCATION:https://researchseminars.org/talk/nhetc/85/ END:VEVENT BEGIN:VEVENT SUMMARY:Thomas Banks (Rutgers) DTSTART:20230511T183000Z DTEND:20230511T193000Z DTSTAMP:20260422T212707Z UID:nhetc/86 DESCRIPTION:Title: T he Density Matrix Of A Causal Diamond\nby Thomas Banks (Rutgers) as pa rt of NHETC Seminar\n\n\nAbstract\nI will review and reinterpret a number of papers from the 1990s\, which indicate that the operator algebra of a c ausal diamond in models of quantum gravity is finite dimensional and that the modular Hamiltonian of the "empty diamond" state has an expectation va lue and fluctuations determined by geometrical properties of the diamond. These universal formulae depend on a view of Einstein's equations as the hydrodynamic equations of the area law for diamond entropy\, which means t hat they are valid beyond any "semi-classical" approximation. A model of quantum gravity consists of finding a quantum system whose hydrodynamics i s consistent with a given solution of Einstein's equations. I will quickl y review many papers and attendees are encouraged to read them before the talk. (List will follow). Among the many implications of these papers is that quantum field theory cannot account for most of the entropy in a cau sal diamond\, and that the cosmological constant should not be thought of as an energy density. \n\nReferences:\n\n 1. A. G. Cohen\, D. B. Kaplan and A. E. Nelson\, Phys. Rev. Lett. 82\, 4971-4974 (1999)doi:10.1103/Phys RevLett.82.4971 [arXiv:hep-th/9803132 [hep-th]].\n\n 2. T. Banks and P. Draper\, Phys. Rev. D 101\, no.12\, 126010 (2020) doi:10.1103/PhysRevD.10 1.126010[arXiv:1911.05778 [hep-th]].\n\n 3. N. Blinov and P. Draper\, P hys. Rev. D 104\, no.7\, 076024 (2021) doi:10.1103/PhysRevD.104.076024[arX iv:2107.03530 [hep-ph]].\n\n 4. R. D. Sorkin\, [arXiv:1402.3589 [gr-qc] ].\n\n 5. M. Srednicki\, Phys. Rev. Lett. 71\, 666-669 (1993) doi:10.11 03/PhysRevLett.71.666[arXiv:hep-th/9303048 [hep-th]].\n\n 6. C. G. Call an\, Jr. and F. Wilczek\, Phys. Lett. B 333\, 55-61 (1994) doi:10.1016/037 0-2693(94)91007-3 [arXiv:hep-th/9401072 [hep-th]].\n\n 7. L. Susskind a nd J. Uglum\, Phys. Rev. D 50\, 2700-2711 (1994) doi:10.1103/PhysRevD.50.2 700[arXiv:hep-th/9401070 [hep-th]].\n\n 8. T. Jacobson\, [arXiv:gr-qc/9 404039 [gr-qc]].\n\n 9. T. Jacobson\, Phys. Rev. Lett. 75\, 1260-1263 ( 1995) doi:10.1103/PhysRevLett.75.1260[arXiv:gr-qc/9504004 [gr-qc]].\n\n 10. W. Fischler and L. Susskind\, [arXiv:hep-th/9806039 [hep-th]].\n\n 11. R. Bousso\, Class. Quant. Grav. 17\, 997-1005 (2000) doi:10.1088/0264 -9381/17/5/309[arXiv:hep-th/9911002 [hep-th]]. ETC.\n\n 12. H. L. Verli nde and E. P. Verlinde\, Nucl. Phys. B 371\, 246-268 (1992) doi:10.1016/05 50-3213(92)90236-5 [arXiv:hep-th/9110017 [hep-th]].\n\n 13. S. Carlip\, Phys. Rev. Lett. 82\, 2828-2831 (1999) doi:10.1103/PhysRevLett.82.2828[ar Xiv:hep-th/9812013 [hep-th]]. ETC.\n\n 14. S. N. Solodukhin\, Phys. Let t. B 454\, 213-222 (1999) doi:10.1016/S0370-2693(99)00398-6[arXiv:hep-th/9 812056 [hep-th]]. \n\n 15. T. Banks and K. M. Zurek\, Phys. Rev. D 104 \, no.12\, 126026 (2021) doi:10.1103/PhysRevD.104.126026[arXiv:2108.04806 [hep-th]].\n LOCATION:https://researchseminars.org/talk/nhetc/86/ END:VEVENT BEGIN:VEVENT SUMMARY:Veronica Pasquarella (University of Cambridge) DTSTART:20230912T183000Z DTEND:20230912T193000Z DTSTAMP:20260422T212707Z UID:nhetc/87 DESCRIPTION:Title: C ategorical Symmetries and Fiber Functors from Multiple Condensing Homomorp hisms from 6D N=(2\,0) SCFTs\nby Veronica Pasquarella (University of C ambridge) as part of NHETC Seminar\n\n\nAbstract\nhis talk is structured i nto two parts\, each one exploiting the symmetry topological field theory /topological order correspondence (SymTFT/TO). On the one hand\, this enab les to further the understanding of the categorical structure arising from dimensional reduction of 6D N = (2\, 0) SCFTs\, identifying a criterion t o distinguish between intrinsic and non-intrinsic non-invertible symmetrie s in terms of the quantum dimension of condensable algebras. On the other\ , it addresses the issue of determining the fiber functor and Drinfeld cen ter for a system of joined absolute theories separated by non invertible d efects. Concluding remarks include the usefulness of these insights for fu rthering the understanding of the interplay between gauge theory\, repres entation theory and 3D mirror symmetry.\n LOCATION:https://researchseminars.org/talk/nhetc/87/ END:VEVENT BEGIN:VEVENT SUMMARY:Hao Lan-Xu (Stony Brook University) DTSTART:20230921T183000Z DTEND:20230921T193000Z DTSTAMP:20260422T212707Z UID:nhetc/88 DESCRIPTION:Title: A nalyticity properties of 2d Ising Field Theories\nby Hao Lan-Xu (Stony Brook University) as part of NHETC Seminar\n\n\nAbstract\nIn this talk\, I will discuss the analyticity properties of 2d Ising field theories (IFTs ). I will start with a short introduction to 2d Ising field theory\, which is the continuous limit of the 2d Ising model on square lattice. Then the different spectrum scenarios for high-T and low-T domains will be introdu ced. Generally speaking\, an IFT which sits not at the critical temperatur e and has a non-vanishing external field is neither solvable nor integrabl e. However\, it's possible to look into the analytical properties of vario us quantities in the theory space\, then further non-perturbative informat ion can be extracted. I will focus on the analyticity properties for mass of the first excitation\, and discuss its critical behaviours and dispersi on relation in both ordered and disordered phase. Finally\, if time allowe d\, I will switch the topic and discuss the analyticity properties of the analytical structure of S-matrices\, and show various related interesting phenomenons together with unsolved questions.\n\nReferences:\n[1] Ising fi eld theory in a magnetic field: Analytic properties of the free energy\, P . Fonseca and A. Zamolodchikov\, hep-th/0112167 [hep-th].\n[2] Ising Spect roscopy II: Particles and poles at T > Tc\, A. Zamolodchikov\, 1310.4821 [ hep-th].\n[3] 2D Ising Field Theory in a magnetic field: the Yang-Lee sing ularity\, H. Xu and A. Zamolodchikov\, 2203.11262 [hep-th].\n[4] On the S- matrix of Ising field theory in two dimensions\, B. Gabai and X. Yin\, 190 5.00710 [hep-th]\n[5] Ising Field Theory in a Magnetic Field: Extended ana lyticity properties of M1\, H. Xu\, in preparation.\n LOCATION:https://researchseminars.org/talk/nhetc/88/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Winer (University of Maryland) DTSTART:20230926T183000Z DTEND:20230926T193000Z DTSTAMP:20260422T212707Z UID:nhetc/89 DESCRIPTION:Title: T he Spectral Form Factor: From Hydrodynamics to the Riemann Zeta Function\nby Michael Winer (University of Maryland) as part of NHETC Seminar\n\n Abstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/89/ END:VEVENT BEGIN:VEVENT SUMMARY:Kathryn Zurek (Caltech) DTSTART:20231010T183000Z DTEND:20231010T193000Z DTSTAMP:20260422T212707Z UID:nhetc/90 DESCRIPTION:by Kathryn Zurek (Caltech) as part of NHETC Seminar\n\nAbstrac t: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/90/ END:VEVENT BEGIN:VEVENT SUMMARY:Dan Freed (Harvard) DTSTART:20231017T183000Z DTEND:20231017T193000Z DTSTAMP:20260422T212707Z UID:nhetc/91 DESCRIPTION:Title: W hat is an anomaly?\nby Dan Freed (Harvard) as part of NHETC Seminar\n\ n\nAbstract\nAnomalies in quantum field theory have been the subject of at tention for decades. In this talk I will dispel some myths: anomalies are tied to symmetry\, anomalies are tied to fermionic fields\, etc. Then I will explain how anomalies--expressed as invertible field theories--are th e manifestation of the projectivity of quantum field theory. My point of view is summarized by a slogan:\n\n Quantum theory is projectiv e. Quantization is linear.\n LOCATION:https://researchseminars.org/talk/nhetc/91/ END:VEVENT BEGIN:VEVENT SUMMARY:Eliezer Rabinovici (CERN) DTSTART:20231024T183000Z DTEND:20231024T193000Z DTSTAMP:20260422T212707Z UID:nhetc/92 DESCRIPTION:Title: S ome Aspects of Krylov Complexity\nby Eliezer Rabinovici (CERN) as part of NHETC Seminar\n\n\nAbstract\nA review of the concept of Krylov Complex ity (K-Complexity) will be presented. One feature of K-Complexity is that its definition does not involve a tolerance parameter. I will describe som e general properties of K-Complexity\, its behavior when interpolating amo ng various types of systems: free\, strongly integrable and chaotic ones. Finally for a certain low dimensional system in a certain state I will des cribe an explicit derivation of the geometric bulk dual of K complexity.\n LOCATION:https://researchseminars.org/talk/nhetc/92/ END:VEVENT BEGIN:VEVENT SUMMARY:Brian Swingle (Brandeis) DTSTART:20231114T193000Z DTEND:20231114T203000Z DTSTAMP:20260422T212707Z UID:nhetc/93 DESCRIPTION:by Brian Swingle (Brandeis) as part of NHETC Seminar\n\nAbstra ct: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/93/ END:VEVENT BEGIN:VEVENT SUMMARY:Akshay Ghalsasi (University of Pittsburgh) DTSTART:20230919T183000Z DTEND:20230919T193000Z DTSTAMP:20260422T212707Z UID:nhetc/94 DESCRIPTION:Title: G ravitational Waves from NNaturalness\nby Akshay Ghalsasi (University o f Pittsburgh) as part of NHETC Seminar\n\n\nAbstract\nNNaturalness provide s a solution to the hierarchy problem by having large number of copies of the standard model. The reheating mechanism is NNaturalness provides energ y density to each of these sectors. The sectors in NNaturalness which have a positive Higgs mass squared have massless quarks and hence can undergo a first order phase transition. The resultant gravitational waves can be o bservable by future gravitational wave observatories providing a unique wi ndow into NNaturalness. I this talk\, I will describe the NNaturalness mec hanism\, and the parameter space of NNaturalness that can be probed by fut ure GW observatories.\n LOCATION:https://researchseminars.org/talk/nhetc/94/ END:VEVENT BEGIN:VEVENT SUMMARY:Yitian Sun (MIT) DTSTART:20231026T183000Z DTEND:20231026T193000Z DTSTAMP:20260422T212707Z UID:nhetc/95 DESCRIPTION:by Yitian Sun (MIT) as part of NHETC Seminar\n\nAbstract: TBA\ n LOCATION:https://researchseminars.org/talk/nhetc/95/ END:VEVENT BEGIN:VEVENT SUMMARY:Shu-Heng Shao (Stony Brook University) DTSTART:20231031T183000Z DTEND:20231031T193000Z DTSTAMP:20260422T212707Z UID:nhetc/96 DESCRIPTION:Title: N on-invertible lattice translation\nby Shu-Heng Shao (Stony Brook Unive rsity) as part of NHETC Seminar\n\n\nAbstract\nI will discuss non-invertib le symmetries in 1+1d lattice models with a tensor-product Hilbert space\, including the transverse-field Ising model and its deformation. The Krame rs-Wannier duality operator on the lattice mixes with the lattice translat ion\, and obeys a different non-invertible algebra compared to the continu um one.\n LOCATION:https://researchseminars.org/talk/nhetc/96/ END:VEVENT BEGIN:VEVENT SUMMARY:Ahsan Khan (IAS) DTSTART:20231214T193000Z DTEND:20231214T203000Z DTSTAMP:20260422T212707Z UID:nhetc/97 DESCRIPTION:Title: H olomorphic Surface Defects in 4d Chern-Simons Theory and the Bethe Equatio ns\nby Ahsan Khan (IAS) as part of NHETC Seminar\n\n\nAbstract\nThere is a remarkable relationship between integrable systems in 1+1 dimensions (such as the Heisenberg spin chain) and a certain quantum gauge theory in four dimensions often referred to as four-dimensional Chern-Simons Theory. I will review aspects of this relationship and then describe some newer r esults involving holomorphic surface defects in this gauge theory and thei r relationship to the Bethe equations governing spin chains.\n LOCATION:https://researchseminars.org/talk/nhetc/97/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Brennan (UC San Diego) DTSTART:20231128T193000Z DTEND:20231128T203000Z DTSTAMP:20260422T212707Z UID:nhetc/98 DESCRIPTION:Title: T he Callan Rubakov Effect\nby Daniel Brennan (UC San Diego) as part of NHETC Seminar\n\n\nAbstract\nThe Callan Rubakov Effect describes the inter action between (massless) fermions and a smooth monopole in 4d gauge theor y. In this scenario\, the fermions can probe the UV physics inside the mon opole core which leads to interesting effects such as proton decay in GUT models. However\, the monopole-fermion scattering appears to lead to out-s tates that are not in the perturbative Hilbert space. In this talk\, we wi ll review this issue and propose a new physical mechanism that resolves th is long-standing confusion.\n LOCATION:https://researchseminars.org/talk/nhetc/98/ END:VEVENT BEGIN:VEVENT SUMMARY:Francois Lanusse (CNRS) DTSTART:20231205T193000Z DTEND:20231205T203000Z DTSTAMP:20260422T212707Z UID:nhetc/99 DESCRIPTION:by Francois Lanusse (CNRS) as part of NHETC Seminar\n\nAbstrac t: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/99/ END:VEVENT BEGIN:VEVENT SUMMARY:Kevin Costello (Perimeter Institute) DTSTART:20231107T193000Z DTEND:20231107T203000Z DTSTAMP:20260422T212707Z UID:nhetc/100 DESCRIPTION:Title: Burns space and celestial holography\nby Kevin Costello (Perimeter Ins titute) as part of NHETC Seminar\n\n\nAbstract\nCelestial holography aims to describe scattering amplitudes of theories on asymptotically flat space times in terms of two-dimensional CFTs. I will describe an explicit top-d own example\, where correlators of a 2d chiral CFT at large N match amplit udes of a 4d theory on an asymptotically flat manifold known as Burns spac e.\n LOCATION:https://researchseminars.org/talk/nhetc/100/ END:VEVENT BEGIN:VEVENT SUMMARY:Lotte Hollands (Heriot-Watt University) DTSTART:20231219T193000Z DTEND:20231219T203000Z DTSTAMP:20260422T212707Z UID:nhetc/101 DESCRIPTION:Title: Non-perturbative partition functions for N=2 theories of class S\nby L otte Hollands (Heriot-Watt University) as part of NHETC Seminar\n\n\nAbstr act\nThe beautiful works by Gaiotto\, Moore and Neitzke have taught us (in particular) how to understand various kinds of BPS spectra for 4d N=2 the ories in terms of certain configurations of curves on a Riemann surface\, called spectral networks. In this talk I'll review how to generate a spect ral network for each point of the 4d Coulomb branch together with the choi ce of a phase. I'll point out that this data corresponds to a boundary con dition for the 4d N=2 theory in the half-Omega background\, and associate to it a new kind of N=2 partition function. This partition function is loc ally constant in the phase\, while its jumps are associated to 4d BPS part icles in the corresponding Coulomb vacuum. The well-known Nekrasov partiti on function (in the half-Omega background) may be recovered in a weakly co upled region of the Coulomb branch (if the theory admits any)\, at a speci al phase corresponding to a Fenchel-Nielsen spectral network. When lifted to five dimensions\, this new partition function becomes the non-perturbat ive topological string partition function.\n LOCATION:https://researchseminars.org/talk/nhetc/101/ END:VEVENT BEGIN:VEVENT SUMMARY:Zohar Komargodski (SCGP) DTSTART:20240123T193000Z DTEND:20240123T203000Z DTSTAMP:20260422T212707Z UID:nhetc/102 DESCRIPTION:Title: The dynamics on Defects in Magnets and Gauge Theories\nby Zohar Komarg odski (SCGP) as part of NHETC Seminar\n\n\nAbstract\nWe define a notion of zero-temperature entropy for impurities (line defects) in d + 1 space-tim e dimensions. We show that this entropy obeys a simple evolution equation under the renormalization group. We apply this result for impurities in ma gnets and in gauge theories. We find new critical impurities and phase tra nsitions. We also discuss constraints from topology on the dynamics of def ects and apply topology for the problem of spontaneous symmetry breaking a nd the Kondo problem in a 2+1 dimensional quantum magnet.\n LOCATION:https://researchseminars.org/talk/nhetc/102/ END:VEVENT BEGIN:VEVENT SUMMARY:Carolina Figueiredo (Princeton) DTSTART:20240130T193000Z DTEND:20240130T203000Z DTSTAMP:20260422T212707Z UID:nhetc/103 DESCRIPTION:Title: Scalars to Pions and Gluons: New structure closer to the real world\nb y Carolina Figueiredo (Princeton) as part of NHETC Seminar\n\n\nAbstract\n Scattering amplitudes for the simplest theory of colored scalars— Tr phi ^3 theory — have been understood as arising from a counting problem asso ciated with curves on a surface (arXiv:2309.15913v1). This formulation pro duces “stringy” integrals for the amplitudes\, built off of variables defined on the surface\, from which the field theory limit as $\\alpha^\\p rime \\to 0$ can easily be extracted. In this talk\, we will extend this a pproach to theories closer to the real world — in particular the non-lin ear sigma model and Yang-Mills theory (arXiv:2401.00041v1). We will explai n how amplitudes in these theories are surprisingly obtained from those of the Tr $\\phi^3$ theory by simple shifts of the kinematic data. We will also explain how these “stringy” formulations expose universal feature s of the amplitudes present in all these colored theories — ranging from hidden patterns of zeroes to unusual factorization properties away from s ingularities (arXiv:2312.16282v1).\n LOCATION:https://researchseminars.org/talk/nhetc/103/ END:VEVENT BEGIN:VEVENT SUMMARY:Ofer Aharony (Weizmann and IAS) DTSTART:20240213T193000Z DTEND:20240213T203000Z DTSTAMP:20260422T212707Z UID:nhetc/104 DESCRIPTION:Title: Two dimensional QCD as a string theory\nby Ofer Aharony (Weizmann and IAS) as part of NHETC Seminar\n\n\nAbstract\n50 years after the duality of large N gauge theories to string theories was suggested\, we still do not have a constructive method to find the string dual of a given gauge theor y. I will review work in progress on two approaches to understanding this\ , in what should perhaps be the simplest case\, namely two dimensional gau ge theories. The first approach uses perturbation theory to obtain an effe ctive stringy description of the high-energy states of 2d QCD with very ma ssive adjoint fermions. The second approach starts from finding a good wor ldsheet description for the string dual to the two dimensional pure Yang-M ills theory\, following past work by Gross-Taylor\, Cordes-Moore-Ramgoolam \, and Horava\; in the future we hope to add to it boundaries (quarks in t he fundamental representation) and/or extra particles on the worldsheet (a djoint matter fields).\n LOCATION:https://researchseminars.org/talk/nhetc/104/ END:VEVENT BEGIN:VEVENT SUMMARY:Francois Lanusse (CNRS) DTSTART:20240326T183000Z DTEND:20240326T193000Z DTSTAMP:20260422T212707Z UID:nhetc/105 DESCRIPTION:by Francois Lanusse (CNRS) as part of NHETC Seminar\n\nAbstrac t: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/105/ END:VEVENT BEGIN:VEVENT SUMMARY:Iñaki Garcia-Etxebarria (Durham\, UK) DTSTART:20240402T183000Z DTEND:20240402T193000Z DTSTAMP:20260422T212707Z UID:nhetc/106 DESCRIPTION:Title: Deriving SymTFTs from geometry\nby Iñaki Garcia-Etxebarria (Durham\, UK) as part of NHETC Seminar\n\n\nAbstract\nSymTFTs (or\, relatedly\, the "sandwich construction") have emerged recently as a useful way to think of categorical symmetries. I will give a brief description of this construct ion\, and then review recent work on how to obtain the SymTFT data from ge ometry in the context of geometric engineering.\n LOCATION:https://researchseminars.org/talk/nhetc/106/ END:VEVENT BEGIN:VEVENT SUMMARY:Ibrahima Bah (Johns Hopkins) DTSTART:20240423T183000Z DTEND:20240423T193000Z DTSTAMP:20260422T212707Z UID:nhetc/107 DESCRIPTION:Title: Aspects of topological symmetry\, holography\, and branes\nby Ibrahima Bah (Johns Hopkins) as part of NHETC Seminar\n\n\nAbstract\nIn this talk I will discuss the holographic duals of topological operators. At low ene rgy sugra\, they can be realized by Page charge associated to Gauss law co nstraints. In the UV string theory\, topological operators can be charact erized by various brane configurations. This provides a way of exploring generalized symmetries with dynamical bulk physics.\n LOCATION:https://researchseminars.org/talk/nhetc/107/ END:VEVENT BEGIN:VEVENT SUMMARY:Iñaki Garcia-Etxebarria (Durham) DTSTART:20240507T183000Z DTEND:20240507T193000Z DTSTAMP:20260422T212707Z UID:nhetc/108 DESCRIPTION:Title: Deriving SymTFTs from geometry\nby Iñaki Garcia-Etxebarria (Durham) a s part of NHETC Seminar\n\n\nAbstract\nSymTFTs (or\, relatedly\, the "sand wich construction") have emerged recently as a useful way to think of cate gorical symmetries. I will give a brief description of this construction\, and then review recent work on how to obtain the SymTFT data from geometr y in the context of geometric engineering.\n LOCATION:https://researchseminars.org/talk/nhetc/108/ END:VEVENT BEGIN:VEVENT SUMMARY:Hao Zhang (University of Tokyo) DTSTART:20240910T183000Z DTEND:20240910T193000Z DTSTAMP:20260422T212707Z UID:nhetc/109 DESCRIPTION:by Hao Zhang (University of Tokyo) as part of NHETC Seminar\n\ nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/109/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Jafferis (Harvard) DTSTART:20240924T183000Z DTEND:20240924T193000Z DTSTAMP:20260422T212707Z UID:nhetc/110 DESCRIPTION:by Daniel Jafferis (Harvard) as part of NHETC Seminar\n\nAbstr act: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/110/ END:VEVENT BEGIN:VEVENT SUMMARY:Nathan Seiberg (IAS) DTSTART:20241001T183000Z DTEND:20241001T193000Z DTSTAMP:20260422T212707Z UID:nhetc/111 DESCRIPTION:by Nathan Seiberg (IAS) as part of NHETC Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/111/ END:VEVENT BEGIN:VEVENT SUMMARY:Eliezer Rabinovici (The Racah Institute of Physics) DTSTART:20241015T183000Z DTEND:20241015T193000Z DTSTAMP:20260422T212707Z UID:nhetc/112 DESCRIPTION:by Eliezer Rabinovici (The Racah Institute of Physics) as part of NHETC Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/112/ END:VEVENT BEGIN:VEVENT SUMMARY:Ping Gao (Rutgers) DTSTART:20250909T183000Z DTEND:20250909T193000Z DTSTAMP:20260422T212707Z UID:nhetc/113 DESCRIPTION:Title: A new probe of non-maximal quantum chaos: pole-skipping of higher spin ope rators\nby Ping Gao (Rutgers) as part of NHETC Seminar\n\n\nAbstract\n Pole-skipping is an independent probe of quantum chaos beyond the Lyapunov exponent. In this talk\, I will explain the pole-skipping of higher spin operators in a higher-dimensional CFT with large N. For such a CFT in the Regge limit\, we will have non-maximal quantum chaos\, which is associated with the leading Regge trajectory. For generic spin J\, there exists a no ntrivial two-piece rule for the distribution of pole-skipping points at bo th positive and negative imaginary frequencies. For the pole-skipping of a n individual spin J operator\, it has nothing to do with the non-maximal L yapunov exponent. However\, if we combine the infinite pole-skipping point s with the largest imaginary Matsubara frequencies\, we will surprisingly find that they form an analytic trajectory\, which gives the non-maximal L yapunov exponent. We conjecture this property holds for generic non-maxima l chaotic systems and verify this conjecture in large q SYK chain.\n LOCATION:https://researchseminars.org/talk/nhetc/113/ END:VEVENT BEGIN:VEVENT SUMMARY:Brandon Rayhaun (IAS) DTSTART:20250923T183000Z DTEND:20250923T193000Z DTSTAMP:20260422T212707Z UID:nhetc/114 DESCRIPTION:Title: Anomalies of Defect Parameter Spaces and a Spin-Flux Duality\nby Brand on Rayhaun (IAS) as part of NHETC Seminar\n\n\nAbstract\nI will introduce the notion of an anomaly in the space of defect coupling constants\, gener alizing an analogous construction of Cordova\, Freed\, Lam\, and Seiberg. I will explain how such anomalies\, together with more standard 't Hooft a nomalies and the irreversibility of the renormalization group\, can be use d to constrain the IR phases of defects in familiar quantum field theories . As an example\, I will use these techniques to provide evidence for a co njectural "spin-flux duality" which describes how certain line operators a re mapped across particle/vortex duality in 2+1d.\n LOCATION:https://researchseminars.org/talk/nhetc/114/ END:VEVENT BEGIN:VEVENT SUMMARY:Anatoly Dymarsky (Kentucky) DTSTART:20251007T183000Z DTEND:20251007T193000Z DTSTAMP:20260422T212707Z UID:nhetc/115 DESCRIPTION:Title: Abelian TQFTs\, codes\, and holography\nby Anatoly Dymarsky (Kentucky) as part of NHETC Seminar\n\n\nAbstract\nIn the first part\, I will show h ow anyon condensation in 3D and 5D Abelian TQFTs naturally gives rise to b oth classical and quantum (error-correcting) codes\, and I will then expla in how codes emerge to describe the TQFT path integral on manifolds with b oundary. In the second part\, I will explain how 3D TQFTs can be consisten tly summed over all topologies\, leading to a well-defined holographic dua l. If time permits\, I will conclude with a discussion of a mass formula t hat evaluates the number of topological boundary conditions from the parti tion function of TQFT gravity.\n LOCATION:https://researchseminars.org/talk/nhetc/115/ END:VEVENT BEGIN:VEVENT SUMMARY:Hongwan Liu (Boston) DTSTART:20250930T183000Z DTEND:20250930T193000Z DTSTAMP:20260422T212707Z UID:nhetc/116 DESCRIPTION:Title: Doing BBN Better\nby Hongwan Liu (Boston) as part of NHETC Seminar\n\n \nAbstract\nBig Bang Nucleosynthesis (BBN) is a cornerstone of modern cosm ology\, providing us with invaluable information about our cosmological hi story. In this talk\, I will discuss some recent and ongoing work aimed at bringing BBN fully into the era of precision cosmology.\n LOCATION:https://researchseminars.org/talk/nhetc/116/ END:VEVENT BEGIN:VEVENT SUMMARY:Vladimir Rosenhaus (CUNY) DTSTART:20251021T183000Z DTEND:20251021T193000Z DTSTAMP:20260422T212707Z UID:nhetc/117 DESCRIPTION:Title: Renormalization Group in far-from-equilibrium states\nby Vladimir Rose nhaus (CUNY) as part of NHETC Seminar\n\n\nAbstract\nWe study renormalizat ion group flows in far-from-equilibrium states. The study is made tractabl e by focusing on states that are spatially homogeneous\, time-independent\ , and scale invariant. Such states\, in which mode k has occupation number $n_k = k^{-\\gamma}$\, are well-known in nonlinear physics (going under t he name of wave turbulence). RG flow in such states is qualitatively diffe rent than in the vacuum -- a positive $\\gamma$ decreases the dimension of an operator\, turning marginal interactions into relevant interactions. W e compute one loop beta functions. Depending on the sign of the beta funct ion\, backreaction may either cause a minor shift of the state in the IR\, or completely change the nature of the state. Focusing on nearly marginal interactions\, we construct an analog of the epsilon expansion and IR fix ed points\, with epsilon now set by the scaling of the interaction rather than the spacetime dimension. In the language of RG flow\, critical balanc e scaling -- having applications in fields as varied as astrophysics and o cean waves -- corresponds to the state dynamically adjusting itself along the RG flow until the interaction becomes marginal.\n LOCATION:https://researchseminars.org/talk/nhetc/117/ END:VEVENT BEGIN:VEVENT SUMMARY:Meng Cheng (Yale) DTSTART:20251028T183000Z DTEND:20251028T193000Z DTSTAMP:20260422T212707Z UID:nhetc/118 DESCRIPTION:Title: Ordering topological orders in quantum Hall systems and beyond\nby Men g Cheng (Yale) as part of NHETC Seminar\n\n\nAbstract\nI will discuss poss ible topological order/topological quantum field theory of quantum Hall sy stems. Given the value of the Hall conductivity\, we constrain the global symmetry of the low-energy theory and its anomaly. This information is pow erful enough to lead to a unique minimal topological order (or a small num ber of minimal topological orders)\, and generally provides an organizing principle for possible topological phases in these systems. Almost all of the known experimentally discovered topological orders are these minimal t heories. I will also discuss applications of these ideas in lattice system s of fermions with a given filling factor.\n LOCATION:https://researchseminars.org/talk/nhetc/118/ END:VEVENT BEGIN:VEVENT SUMMARY:Sahand Seifnashri (IAS) DTSTART:20251104T193000Z DTEND:20251104T203000Z DTSTAMP:20260422T212707Z UID:nhetc/119 DESCRIPTION:Title: Symmetry Transmutation\nby Sahand Seifnashri (IAS) as part of NHETC Se minar\n\n\nAbstract\nWe begin with a review of generalized global symmetri es and some of their applications. Next\, we describe the phenomenon of sy mmetry transmutation\, in which an ordinary global symmetry in the UV theo ry transmutes into a generalized higher-form symmetry in the effective low -energy theory. Notably\, transmuted symmetries are exact rather than acci dental. We then discuss gauge theory examples in which the anomaly of the UV symmetry is matched by the anomaly of the transmuted symmetry in the IR . Finally\, we discuss symmetry transmutation in QCD.\n LOCATION:https://researchseminars.org/talk/nhetc/119/ END:VEVENT BEGIN:VEVENT SUMMARY:Anirudh Prabhu (Princeton) DTSTART:20251118T193000Z DTEND:20251118T203000Z DTSTAMP:20260422T212707Z UID:nhetc/120 DESCRIPTION:by Anirudh Prabhu (Princeton) as part of NHETC Seminar\n\nAbst ract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/120/ END:VEVENT BEGIN:VEVENT SUMMARY:Keisuke Inomata (Johns Hopkins) DTSTART:20251125T193000Z DTEND:20251125T203000Z DTSTAMP:20260422T212707Z UID:nhetc/121 DESCRIPTION:Title: Self-scattering of inflaton during inflation\nby Keisuke Inomata (John s Hopkins) as part of NHETC Seminar\n\n\nAbstract\nInflationary models pre dicting a scale-dependent large amplification of the density perturbations have recently attracted a lot of attention because the amplified perturba tions can seed a sizable amount of primordial black holes and stochastic b ackground of gravitational waves. While power spectra in these models are often computed ignoring the inflaton self-scattering\, the self-scattering (or loop correction) is generally non-negligible in such inflation models with large amplification of perturbations. In this talk\, I will highligh t what changes and remains unchanged by inflaton self-scattering during in flation.\nReferences: arXiv:2211.02586\, 2403.04682\, 2403.12811\, 2502.08 707\, and 2502.12112\n LOCATION:https://researchseminars.org/talk/nhetc/121/ END:VEVENT BEGIN:VEVENT SUMMARY:Nima Laal (Vanderbilt) DTSTART:20251209T193000Z DTEND:20251209T203000Z DTSTAMP:20260422T212707Z UID:nhetc/122 DESCRIPTION:by Nima Laal (Vanderbilt) as part of NHETC Seminar\n\nAbstract : TBA\n LOCATION:https://researchseminars.org/talk/nhetc/122/ END:VEVENT BEGIN:VEVENT SUMMARY:Aurelien Dersy (Harvard) DTSTART:20251014T183000Z DTEND:20251014T193000Z DTSTAMP:20260422T212707Z UID:nhetc/123 DESCRIPTION:Title: Learning the Language of Scattering Amplitudes\nby Aurelien Dersy (Har vard) as part of NHETC Seminar\n\n\nAbstract\nMachine learning (ML) has gr own dramatically in high-energy physics in recent years. Tasks such as cla ssification\, regression\, anomaly detection\, and density estimation now benefit from modern ML approaches that often outperform traditional baseli nes. Far less attention\, however\, has gone to the theoretical side\, eve n though (symbolic) data is plentiful. In this talk\, I will discuss how m odern models can help bridge this gap and “learn the language” of scat tering amplitudes. In particular\, I will describe recent work on simplify ing amplitude expressions\, reconstructing S-matrix phases\, and recoverin g exact analytic formulas.\n LOCATION:https://researchseminars.org/talk/nhetc/123/ END:VEVENT BEGIN:VEVENT SUMMARY:Adrian Bayer (Princeton) DTSTART:20251111T193000Z DTEND:20251111T203000Z DTSTAMP:20260422T212707Z UID:nhetc/124 DESCRIPTION:by Adrian Bayer (Princeton) as part of NHETC Seminar\n\nAbstra ct: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/124/ END:VEVENT BEGIN:VEVENT SUMMARY:Jeff Harvey (Chicago) DTSTART:20251202T193000Z DTEND:20251202T203000Z DTSTAMP:20260422T212707Z UID:nhetc/125 DESCRIPTION:Title: Level-Rank Duality\, Anyon Condensation\, and Holomorphic CFT\nby Jeff Harvey (Chicago) as part of NHETC Seminar\n\n\nAbstract\nI will discuss r elations between the three topics in the title.\n LOCATION:https://researchseminars.org/talk/nhetc/125/ END:VEVENT BEGIN:VEVENT SUMMARY:Nathan Seiberg (IAS) DTSTART:20260120T193000Z DTEND:20260120T203000Z DTSTAMP:20260422T212707Z UID:nhetc/126 DESCRIPTION:Title: Symmetry\, Anomaly\, Gauging\, Proliferation\, and Condensation\nby Na than Seiberg (IAS) as part of NHETC Seminar\n\n\nAbstract\nIn the study of topological quantum field theories in 2+1 dimensions\, it is common to\np erform an operation known as “anyon condensation.” This term is mislea ding. Two\nmore appropriate terms for this operation are “gauging a one- form symmetry” or “anyon\nproliferation.” Interestingly\, these two terms are similar\, but not identical. We will clarify\nthese different no tions and use this insight to analyze various phase transitions out of a\n given topological order.\n LOCATION:https://researchseminars.org/talk/nhetc/126/ END:VEVENT BEGIN:VEVENT SUMMARY:Carolina Figueiredo (Princeton) DTSTART:20260127T193000Z DTEND:20260127T203000Z DTSTAMP:20260422T212707Z UID:nhetc/127 DESCRIPTION:Title: Large $n$: scattering amplitudes at large multiplicity\nby Carolina Fi gueiredo (Princeton) as part of NHETC Seminar\n\n\nAbstract\nWhat happens when we scatter a large number $n$ of particles\, say with $n = 10^1000$? This question is out of reach of all existing approaches to scattering amp litudes\, whether directly through Feynman diagrams or recursion relations . In this talk\, I will study this problem at tree-level for a simple scal ar theory\, Tr($\\phi^3$) theory\, and describe a new way of accessing thi s regime\, starting from the "tropical" representation of the amplitudes g iven by the formalism of surfaceology. Remarkably\, we find that at large $n$ the sum over diagrams "smooths out". Working at leading order in $n$\ , and in certain "positive" regions of kinematic space\, the final answer is astonishingly simple\, given by a single term\, determined by an optimi zation problem associated with a biased random walk. I will also describe a transformation from the tropical representation to a new "dual" theory f or amplitudes\, which in simple limits reduces to the motion of a particle on a half-line\, evolving for a "time'' $n$\, allowing us to systematical ly extract the $1/n$ expansion of the amplitude. I will end by explaining how these results generalize to other large $n$ contexts\, from the scatte ring of pions\, to string scattering at ultra-high energies.\n LOCATION:https://researchseminars.org/talk/nhetc/127/ END:VEVENT BEGIN:VEVENT SUMMARY:Subhajit Ghosh (UT Austin) DTSTART:20260203T193000Z DTEND:20260203T203000Z DTSTAMP:20260422T212707Z UID:nhetc/128 DESCRIPTION:by Subhajit Ghosh (UT Austin) as part of NHETC Seminar\n\nAbst ract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/128/ END:VEVENT BEGIN:VEVENT SUMMARY:Patrick Draper (UIUC) DTSTART:20260210T193000Z DTEND:20260210T203000Z DTSTAMP:20260422T212707Z UID:nhetc/129 DESCRIPTION:by Patrick Draper (UIUC) as part of NHETC Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/129/ END:VEVENT BEGIN:VEVENT SUMMARY:Hong Liu (MIT) DTSTART:20260303T193000Z DTEND:20260303T203000Z DTSTAMP:20260422T212707Z UID:nhetc/130 DESCRIPTION:Title: "Filtering" CFTs at large N: Euclidean Wormholes\, Closed Universes\, and Black Hole Interiors\nby Hong Liu (MIT) as part of NHETC Seminar\n\n\n Abstract\nDespite its successes\, the large-N holographic dictionary remai ns incomplete. Key features of gravitational path integrals--most notably Euclidean wormholes and the associated failure of factorization--lack a cl ear interpretation in the standard large-N framework. In this talk\, we di scuss a resolution of the puzzle by introducing a large-N filter\, which p rovides an intrinsic boundary definition of gravitational "averages\,'' an d a boundary explanation of the origin of wormholes as well as their ampli tudes. In addition\, we derive an infinite tower of inequalities constrain ing wormhole amplitudes. \n\nBeyond resolving factorization\, the large-N filter supplies a generalized framework from which richer Lorentzian space time structures can emerge\, including closed universes and black hole int eriors. We argue that both closed universes and black hole interiors are q uantum volatile\, and that an AdS spacetime entangled with a baby universe is likewise quantum volatile. This volatility may allow an observer in Ad S to infer the existence of the baby universe\, whereas for an infalling o bserver crossing a black hole horizon\, the ability to make measurements a fter may become fundamentally limited--even if they may not live long eno ugh to notice.\n LOCATION:https://researchseminars.org/talk/nhetc/130/ END:VEVENT BEGIN:VEVENT SUMMARY:Iñaki García Etxebarria (Durham University) DTSTART:20260310T183000Z DTEND:20260310T193000Z DTSTAMP:20260422T212707Z UID:nhetc/131 DESCRIPTION:Title: Symmetry TFTs for Continuous Spacetime Symmetries\nby Iñaki García E txebarria (Durham University) as part of NHETC Seminar\n\n\nAbstract\nI wi ll discuss our recent proposal for the Symmetry Topological Field Theory ( SymTFT) for global\, continuous spacetime symmetries (https://arxiv.org/ab s/2509.07965). For a d-dimensional theory\, it is given by a (d + 1)-dimen sional BF-theory for the spacetime symmetry group\, and whenever d is even \, it includes also Chern-Simons couplings\, that encode conformal and gra vitational anomalies. This proposal is supported by the similarity to two- dimensional Jackiw-Teitelboim gravity in the d = 1 case and the topologica l limit of four-dimensional gravity in the d = 3 case. I will discuss how topological defects constructed from this SymTFT act by applying the assoc iated spacetime symmetry transformation. Finally\, I will discuss the rela tion to gravity and holography.\n LOCATION:https://researchseminars.org/talk/nhetc/131/ END:VEVENT BEGIN:VEVENT SUMMARY:Shu-Heng Shao (MIT) DTSTART:20260324T183000Z DTEND:20260324T193000Z DTSTAMP:20260422T212707Z UID:nhetc/132 DESCRIPTION:Title: Lattice chiral symmetry from bosons in 3+1d\nby Shu-Heng Shao (MIT) as part of NHETC Seminar\n\n\nAbstract\nWe present an explicit  Hamiltonian that realizes an exact lattice chiral $U(1)_V \\times U(1)_A$ recently pr oposed. Nielsen-Ninomiya-type no-go theorems are evaded by using lattice b osons rather than fermions. The continuum limit is a compact boson field t heory with an axion-like coupling. While $U(1)_V$ shifts the lattice scala r\, $U(1)_A$ acts on short axion string excitations. We demonstrate the ch iral anomaly by showing that $U(1)_A$ is broken when $U(1)_V$ is gauged. F inally\, gauging either $U(1)_V$ and $U(1)_A$ leads to lattice non-inverti ble and 2-group symmetries\, respectively.\n LOCATION:https://researchseminars.org/talk/nhetc/132/ END:VEVENT BEGIN:VEVENT SUMMARY:Marius Kongsore (New York University) DTSTART:20260407T183000Z DTEND:20260407T193000Z DTSTAMP:20260422T212707Z UID:nhetc/133 DESCRIPTION:by Marius Kongsore (New York University) as part of NHETC Semi nar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/133/ END:VEVENT BEGIN:VEVENT SUMMARY:Ibrahima Bah (Johns Hopkins University) DTSTART:20260414T183000Z DTEND:20260414T193000Z DTSTAMP:20260422T212707Z UID:nhetc/134 DESCRIPTION:Title: Aspects of locality\, unitarity\, and symmetries\nby Ibrahima Bah (Joh ns Hopkins University) as part of NHETC Seminar\n\n\nAbstract\nIn this tal k\, I will explore some aspects of the apparent tension between locality a nd unitarity for symmetries in quantum field theory. I will then discuss h ow locality can impose regularity conditions on the Hilbert space\, and us e this to define an observable that measures the non-locality of symmetry operators. In examples\, this observable encodes data about the fusion alg ebra of the symmetries.\n LOCATION:https://researchseminars.org/talk/nhetc/134/ END:VEVENT BEGIN:VEVENT SUMMARY:Matthias Gaberdiel (ETH Zurich) DTSTART:20260421T183000Z DTEND:20260421T193000Z DTSTAMP:20260422T212707Z UID:nhetc/135 DESCRIPTION:Title: Strings on AdS3 x S3 x S3 x S1 and their CFT duals\nby Matthias Gaberd iel (ETH Zurich) as part of NHETC Seminar\n\n\nAbstract\nMy talk will cons ist of two parts: I will first explain the CFT dual of tensionless string theory on AdS3 x S3 x S3 x S1 with pure NS-NS flux. I will then describe a proposal for the weakly coupled CFT dual of the D1-D5-D5' system.\n LOCATION:https://researchseminars.org/talk/nhetc/135/ END:VEVENT BEGIN:VEVENT SUMMARY:Sarunas Verner (U. Chicago) DTSTART:20260428T183000Z DTEND:20260428T193000Z DTSTAMP:20260422T212707Z UID:nhetc/136 DESCRIPTION:by Sarunas Verner (U. Chicago) as part of NHETC Seminar\n\nInt eractive livestream: https://rutgers.zoom.us/j/94699297301?pwd=SVJieHRUYUt mZmRCbGZKQlBTMTRPdz09\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/136/ URL:https://rutgers.zoom.us/j/94699297301?pwd=SVJieHRUYUtmZmRCbGZKQlBTMTRP dz09 END:VEVENT BEGIN:VEVENT SUMMARY:Walter Tangrife (Loyola University\, Chicago) DTSTART:20260505T183000Z DTEND:20260505T193000Z DTSTAMP:20260422T212707Z UID:nhetc/137 DESCRIPTION:by Walter Tangrife (Loyola University\, Chicago) as part of NH ETC Seminar\n\nInteractive livestream: https://rutgers.zoom.us/j/946992973 01?pwd=SVJieHRUYUtmZmRCbGZKQlBTMTRPdz09\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/137/ URL:https://rutgers.zoom.us/j/94699297301?pwd=SVJieHRUYUtmZmRCbGZKQlBTMTRP dz09 END:VEVENT BEGIN:VEVENT SUMMARY:Melissa Diamond (McGill) DTSTART:20260512T183000Z DTEND:20260512T193000Z DTSTAMP:20260422T212707Z UID:nhetc/138 DESCRIPTION:by Melissa Diamond (McGill) as part of NHETC Seminar\n\nIntera ctive livestream: https://rutgers.zoom.us/j/94699297301?pwd=SVJieHRUYUtmZm RCbGZKQlBTMTRPdz09\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/138/ URL:https://rutgers.zoom.us/j/94699297301?pwd=SVJieHRUYUtmZmRCbGZKQlBTMTRP dz09 END:VEVENT BEGIN:VEVENT SUMMARY:Moritz Münchmeyer (University of Wisconsin-Madison) DTSTART:20260217T193000Z DTEND:20260217T203000Z DTSTAMP:20260422T212707Z UID:nhetc/140 DESCRIPTION:Title: AI Reasoning in Theoretical Physics with TPBench and MadEvolve\nby Mor itz Münchmeyer (University of Wisconsin-Madison) as part of NHETC Seminar \n\n\nAbstract\nLarge-language models are now powerful enough to assist ph ysicists with mathematical reasoning at research level. In this talk\, I w ill first present our dataset TPBench (tpbench.org)\, which was constructe d to benchmark and improve AI models specifically for theoretical physics. I will then discuss how test-time scaling and symbolic verification can b e used to improve their performance and reliability. In the second part of my talk I will present MadEvolve\, our new LLM-based system to iterativel y improve scientific algorithms. I will show that MadEvolve can set state- of-the-art results for algorithms in computational cosmology\, such as the reconstruction of initial conditions of the universe. Finally\, I will br iefly present preliminary work on reinforcement learning fine-tuning of re asoning for theoretical physics.\n LOCATION:https://researchseminars.org/talk/nhetc/140/ END:VEVENT BEGIN:VEVENT SUMMARY:Yuan-Sen Ting (Ohio State University) DTSTART:20260224T193000Z DTEND:20260224T203000Z DTSTAMP:20260422T212707Z UID:nhetc/141 DESCRIPTION:by Yuan-Sen Ting (Ohio State University) as part of NHETC Semi nar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/141/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Harlow (MIT) DTSTART:20260317T183000Z DTEND:20260317T193000Z DTSTAMP:20260422T212707Z UID:nhetc/142 DESCRIPTION:Title: Observers\, alpha parameters\, and the Hartle-Hawking state\nby Daniel Harlow (MIT) as part of NHETC Seminar\n\n\nAbstract\nIn this talk I will clear up some misunderstandings about the gravitational path integral and quantum gravity in a closed universe. I will explain that there are reall y three inequivalent versions of the path integral\, each of which appears in various applications. For example I will explain why the closed strin g Hilbert space is not one-dimensional\, and also why Coleman's \\alpha-pa rameters do not resolve the black hole information problem. I will explai n a connection between recent proposals for using an observer to resolve t he one-dimensional Hilbert space problem and the coarse-grained spectral f orm factor in AdS/CFT\, and I will also explain the (nontrivial) relations hip between the Hartle-Hawking state and the unique state of holographic c osmology.\n LOCATION:https://researchseminars.org/talk/nhetc/142/ END:VEVENT BEGIN:VEVENT SUMMARY:Mariel Pettee (Ohio State University) DTSTART:20260331T183000Z DTEND:20260331T193000Z DTSTAMP:20260422T212707Z UID:nhetc/143 DESCRIPTION:by Mariel Pettee (Ohio State University) as part of NHETC Semi nar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/nhetc/143/ END:VEVENT BEGIN:VEVENT SUMMARY:Yuan-Sen Ting (Ohio State University) DTSTART:20260312T183000Z DTEND:20260312T193000Z DTSTAMP:20260422T212707Z UID:nhetc/144 DESCRIPTION:Title: Expediting Astronomical Discovery with AI Agents\nby Yuan-Sen Ting (Oh io State University) as part of NHETC Seminar\n\n\nAbstract\nThe expansive \, interdisciplinary nature of astronomy\, combined with its open-access c ulture\, makes it an ideal testing ground for exploring how Large Language Models (LLMs) can accelerate scientific discovery. In this talk\, I will present our recent advances in applying LLMs as autonomous research agents . We demonstrate that AI agents now achieve gold-medal performance on Inte rnational Astronomy Olympiad problems\, and that multi-agent frameworks li ke Mephisto can conduct end-to-end galaxy spectral fitting—iteratively r efining physical models and accumulating knowledge through self-play\, app roaching human-like intuition and domain reasoning. However\, the Moravec paradox manifests clearly: tasks requiring abstract calculation may be eas ier for AI than seemingly simple perceptual tasks like chart reading and v isual reasoning\, which remain key bottlenecks. To address the cost barrie r at scale\, we developed open-source specialized models (AstroSage) that match frontier performance on astronomy Q&A at a fraction of the cost. I w ill conclude by reflecting on the epistemological implications—what coun ts as knowledge and understanding when AI agents can reason but not yet pe rceive the way scientists do\, and what this means for the future of astro nomical discovery.\n LOCATION:https://researchseminars.org/talk/nhetc/144/ END:VEVENT END:VCALENDAR