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BEGIN:VEVENT
SUMMARY:Aswin Balasubramanian (Rutgers)
DTSTART;VALUE=DATE-TIME:20200512T190000Z
DTEND;VALUE=DATE-TIME:20200512T200000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20201013T190000Z
DTEND;VALUE=DATE-TIME:20201013T200000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20201027T190000Z
DTEND;VALUE=DATE-TIME:20201027T200000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20201103T200000Z
DTEND;VALUE=DATE-TIME:20201103T210000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210223T180000Z
DTEND;VALUE=DATE-TIME:20210223T190000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210309T180000Z
DTEND;VALUE=DATE-TIME:20210309T190000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210323T170000Z
DTEND;VALUE=DATE-TIME:20210323T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210406T170000Z
DTEND;VALUE=DATE-TIME:20210406T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210420T170000Z
DTEND;VALUE=DATE-TIME:20210420T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210126T183000Z
DTEND;VALUE=DATE-TIME:20210126T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210209T183000Z
DTEND;VALUE=DATE-TIME:20210209T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210413T170000Z
DTEND;VALUE=DATE-TIME:20210413T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210504T170000Z
DTEND;VALUE=DATE-TIME:20210504T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210907T170000Z
DTEND;VALUE=DATE-TIME:20210907T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210914T170000Z
DTEND;VALUE=DATE-TIME:20210914T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210921T170000Z
DTEND;VALUE=DATE-TIME:20210921T180000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20210928T183000Z
DTEND;VALUE=DATE-TIME:20210928T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211012T160000Z
DTEND;VALUE=DATE-TIME:20211012T170000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211026T183000Z
DTEND;VALUE=DATE-TIME:20211026T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211102T183000Z
DTEND;VALUE=DATE-TIME:20211102T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211109T193000Z
DTEND;VALUE=DATE-TIME:20211109T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211116T193000Z
DTEND;VALUE=DATE-TIME:20211116T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211130T193000Z
DTEND;VALUE=DATE-TIME:20211130T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211207T193000Z
DTEND;VALUE=DATE-TIME:20211207T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211005T183000Z
DTEND;VALUE=DATE-TIME:20211005T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211019T183000Z
DTEND;VALUE=DATE-TIME:20211019T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20211123T193000Z
DTEND;VALUE=DATE-TIME:20211123T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220222T193000Z
DTEND;VALUE=DATE-TIME:20220222T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220201T193000Z
DTEND;VALUE=DATE-TIME:20220201T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220215T213000Z
DTEND;VALUE=DATE-TIME:20220215T223000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220301T193000Z
DTEND;VALUE=DATE-TIME:20220301T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220308T193000Z
DTEND;VALUE=DATE-TIME:20220308T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220322T183000Z
DTEND;VALUE=DATE-TIME:20220322T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220329T183000Z
DTEND;VALUE=DATE-TIME:20220329T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220405T183000Z
DTEND;VALUE=DATE-TIME:20220405T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220412T183000Z
DTEND;VALUE=DATE-TIME:20220412T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220419T183000Z
DTEND;VALUE=DATE-TIME:20220419T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220426T183000Z
DTEND;VALUE=DATE-TIME:20220426T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220503T183000Z
DTEND;VALUE=DATE-TIME:20220503T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220208T193000Z
DTEND;VALUE=DATE-TIME:20220208T203000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220315T183000Z
DTEND;VALUE=DATE-TIME:20220315T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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;VALUE=DATE-TIME:20220517T183000Z
DTEND;VALUE=DATE-TIME:20220517T193000Z
DTSTAMP;VALUE=DATE-TIME:20220528T202858Z
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
END:VCALENDAR