BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Brian Skinner (Ohio State UNiversity) DTSTART:20201014T171500Z DTEND:20201014T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/1 DESCRIPTION:Title: M easurement-induced Phase Transitions in the Dynamics of Quantum Entangleme nt\nby Brian Skinner (Ohio State UNiversity) as part of VSF Long Range Colloquium\n\n\nAbstract\nWhen a quantum system evolves under unitary dyn amics\, as produced by either a Hamiltonian or by a sequence of quantum ga tes\, its various component parts tend to become more entangled with each other. Making measurements\, on the other hand\, tends to reduce this enta nglement by collapsing some of the system's degrees of freedom. In this ta lk we explore what happens to the entanglement when a quantum many-body sy stem undergoes both unitary evolution and sporadic measurements. We show t hat the competition between these two effects leads to a new kind of dynam ical phase transition\, such that when the measurement rate is lower than a critical value the dynamics is "entangling"\, while a higher-than-critic al measurement rate leads to a "disentangling" phase. We study this transi tion both in one-dimensional spin chains and in "all-to-all" coupled syste ms\, for which unitary operators can directly couple any two degrees of fr eedom. In both cases the qualitative features of the transition can be und erstood by mapping to a problem of classical percolation\, and in the all- to-all case some features of the transition can be understood exactly.\n LOCATION:https://researchseminars.org/talk/VSFLRC/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Natalia Ares (University of Oxford) DTSTART:20201028T171500Z DTEND:20201028T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/2 DESCRIPTION:Title: M easuring and tuning quantum devices faster than human experts\nby Nata lia Ares (University of Oxford) as part of VSF Long Range Colloquium\n\nAb stract: TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Jennifer Cano (Stony Brook University) DTSTART:20201111T181500Z DTEND:20201111T194500Z DTSTAMP:20260422T225720Z UID:VSFLRC/3 DESCRIPTION:Title: H igher magic angles in twisted bilayer graphene and topological twistronics \nby Jennifer Cano (Stony Brook University) as part of VSF Long Range Colloquium\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Deji Akinwande (University of Texas at Austin) DTSTART:20201209T181500Z DTEND:20201209T194500Z DTSTAMP:20260422T225720Z UID:VSFLRC/4 DESCRIPTION:Title: 2 D materials: From atoms to applications\nby Deji Akinwande (University of Texas at Austin) as part of VSF Long Range Colloquium\n\n\nAbstract\nT his talk will present our latest research adventures on 2D nanomaterials t owards greater scientific understanding and advanced engineering applicati ons. In particular\, the talk will highlight our work on flexible electron ics\, zero-power devices\, monolayer memory (atomristors)\, non-volatile R F switches\, and wearable tattoo sensors. Non-volatile memory devices base d on 2D materials represent an application of defects and are a rapidly ad vancing field with rich physics that can be attributed to sulfur vacancies or metal diffusion. Atomistic modeling and atomic-resolution imaging are contemporary tools used to elucidate the memory phenomena in these systems . Likewise\, from a practical point of view\, electronic tattoos based on graphene have ushered a new material platform that has highly desirable pr actical attributes including optical transparency\, mechanical imperceptib ility\, and is the thinnest conductive electrode sensor that can be integr ated on skin for physiological measurements.\n LOCATION:https://researchseminars.org/talk/VSFLRC/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Leonid Levitov (MIT) DTSTART:20210120T181500Z DTEND:20210120T194500Z DTSTAMP:20260422T225720Z UID:VSFLRC/5 DESCRIPTION:Title: E lectrons Bloch-waltzing in Moire superlattices\nby Leonid Levitov (MIT ) as part of VSF Long Range Colloquium\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Young (UCSB) DTSTART:20210203T181500Z DTEND:20210203T194500Z DTSTAMP:20260422T225720Z UID:VSFLRC/6 DESCRIPTION:Title: O rbital magnetism in graphene heterostructures\nby Andrea Young (UCSB) as part of VSF Long Range Colloquium\n\n\nAbstract\nThe earliest reports o f ferromagnetism date to Thales of Miletus who lived and wrote around 600 BC. Thales noted the ability of natural magnetite to attract iron\, and is said to have taken this as proof that matter itself was alive. Our theori es of magnetism have evolved considerably since then: we now know that fer romagnetism arises from the interplay of the Coulomb repulsion between ele ctrons and their fermionic statistics. However\, in one sense our science has advanced only little: the vast majority of magnets\, like magnetite\, consist of ordered arrangements of the electron spins stabilized by the sp in orbit interaction. In my talk\, I will describe a new class of magnets based on the spontaneous alignment of electron orbitals. Such orbital ferr omagnetism may be a generic phenomena\, but has\, to date\, found its full est expression in graphene heterostructures in which the two dimensional o rbits of electrons in distinct momentum space valleys provide the underlyi ng degree of freedom. Because orbital degrees of freedom arise directly fr om the band wavefunctions\, they are uniquely susceptible to experimental control via materials design. Orbital magnets also enable new forms of mag netic control using in situ knobs. For instance\, orbital magnets in moire superlattice systems\, where the band structure features nontrivial topol ogy\, allow for field-effect switching of magnetic moments and the resulti ng quantized anomalous Hall effects. I will conclude with an outlook for r ealizing more exotic topological phases of matter based on orbital magneti sm.\n LOCATION:https://researchseminars.org/talk/VSFLRC/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Xie Chen (Caltech) DTSTART:20210217T181500Z DTEND:20210217T194500Z DTSTAMP:20260422T225720Z UID:VSFLRC/7 DESCRIPTION:Title: F racton and Chern-Simons Theory\nby Xie Chen (Caltech) as part of VSF L ong Range Colloquium\n\n\nAbstract\nFracton order describes the peculiar p henomena that point excitations in certain strongly interacting systems ei ther cannot move at all or are only allowed to move in a lower dimensional sub-manifold. It has recently been discovered in various lattice models\, tensor gauge theories\, etc. In this talk\, we discuss how another powerf ul field theory framework -- the 2+1D Chern-Simons (CS) gauge theory -- ca n be used to provide new insight and explore new possibilities in 3+1D fra cton order. 2+1D U(1) gauge theories with a CS term provide a simple and c omplete characterization of 2+1D Abelian topological orders. To study 3+1D fracton order\, we extend the theory by taking the number of component ga uge fields to be infinity. In the simplest case of infinite-component CS g auge theory\, different components do not couple to each other and the the ory describes a decoupled stack of 2+1D fractional Quantum Hall systems wi th quasi-particles moving only in 2D planes -- hence a fractonic system. M ore interestingly\, we find that when the component gauge fields do couple through the CS term\, more varieties of fractonic orders are possible. Fo r example\, they may describe foliated fractonic systems which extends the framework found in exactly solvable models. Moreover\, we find examples w hich lie beyond the foliation framework\, characterized by 2D excitations of infinite order and braiding statistics that are not strictly local.\n LOCATION:https://researchseminars.org/talk/VSFLRC/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Monika Aidelsburger (LMU Munich) DTSTART:20210303T181500Z DTEND:20210303T194500Z DTSTAMP:20260422T225720Z UID:VSFLRC/8 DESCRIPTION:Title: U ltracold atoms in optical lattices out-of-equilibrium\nby Monika Aidel sburger (LMU Munich) as part of VSF Long Range Colloquium\n\n\nAbstract\nW ell-controlled synthetic quantum systems\, such as ultracold atoms in opti cal lattices\, offer intriguing possibilities to study complex many-body p roblems relevant to a variety of research areas\, ranging from condensed m atter to high-energy physics. In particular\, out-of-equilibrium phenomena constitute natural applications of quantum simulators\, which have alread y successfully demonstrated simulations in regimes that are beyond reach u sing state-of-the-art numerical techniques.\nThis enables us to shed new l ight on fundamental questions about the thermalization of isolated quantum many-body systems. While generic models are expected to thermalize accord ing to the eigenstate thermalization hypothesis (ETH)\, violation of ETH i s believed to occur mainly in two types of systems: integrable models and many-body localized systems. In between these two extreme limits there is\ , however\, a whole range of models that exhibit more complex dynamics\, f or instance\, due to an emergent fragmentation of the Hilbert space into m any dynamically disconnected subspaces. Here\, we realize such a model by implementing the 1D Fermi-Hubbard model with a strong linear potential [1] and observe strong initial-state dependent thermalization - a smoking-gun signature of Hilbert-space fragmentation.\nEngineering quantum systems ou t-of-equilibrium\, on the other hand\, further can be used as a tool to en gineer novel quantum phases of matter\, which cannot be accessed in static realizations. To this end\, the system’s parameters are varied periodic ally\, a method commonly known as Floquet engineering [2]. This facilitate d the realization of paradigmatic topological lattice models and recently inspired ideas for implementing Z2 lattice gauge theories [3]. The rich pr operties of topological Floquet systems\, however\, transcend those of the ir static counterparts\, resulting in a generalized bulk-edge corresponden ce. As a consequence\, topological edge modes can exist even in situations where the bulk bands have zero Chern numbers. The novel properties of suc h anomalous Floquet systems open the door to exciting new non- equilibrium many-body phases without any static analogue [4].\n\n[1] S. Scherg et al. \, arXiv:2010.12965 (2020)\n[2] A. Eckardt\, Phys. Mod. Phys. 89\, 311 (20 17)\n[3] C. Schweizer et al.\, Nat. Phys. 15\, 1168-1173 (2019)\n[4] K. Wi ntersperger et al.\, Nature Physics 16\, 1058-1063 (2020)\n LOCATION:https://researchseminars.org/talk/VSFLRC/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Andy Mackenzie (Max Planck Institute for Chemical Physics of Solid s) DTSTART:20210331T171500Z DTEND:20210331T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/9 DESCRIPTION:Title: B enefits of good old-fashioned crystalline perfection - new physics in ultr a pure delafossite metals\nby Andy Mackenzie (Max Planck Institute fo r Chemical Physics of Solids) as part of VSF Long Range Colloquium\n\nAbst ract: TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Andreas Wallraff (ETH Zürich) DTSTART:20210414T171500Z DTEND:20210414T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/10 DESCRIPTION:Title: Microwave Networks for Solid State Quantum Information Processors\nby Andreas Wallraff (ETH Zürich) as part of VSF Long Range Colloquium\n\n\nA bstract\nQuantum computing is a radically new approach to processing infor mation. It is one of the approaches which has the potential to address the ever-growing need of society\, industry and research for computing power. At ETH Zurich\, we have designed\, realized and tested a first data link which allows superconducting-circuit-based quantum processors located in d ifferent systems to directly exchange quantum information [1]. This link\, for a quantum computer\, takes the role of a network transferring data be tween computing nodes located in a high-performance computing data center. However\, unlike its conventional counterparts\, our data link is operate d at ultra-low temperatures\, close to the absolute zero. This allows our quantum data link to directly connect to quantum processors operating at t he same temperature [2]. The system we have constructed is a first of its kind in the world and could play an important role in growing the power of quantum computers in the future.\n\n[1] P. Magnard et al.\, Phys. Rev. Le tt. 125\, 260502 (2020)\n[2] P. Kurpiers et al.\, Nature 558\, 264-267 (20 18)\n LOCATION:https://researchseminars.org/talk/VSFLRC/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Sentef (Max Planck Institute for the Structure and Dynamic s of Matter) DTSTART:20210428T171500Z DTEND:20210428T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/11 DESCRIPTION:Title: Cavity quantum materials\nby Michael Sentef (Max Planck Institute for the Structure and Dynamics of Matter) as part of VSF Long Range Colloquium \n\n\nAbstract\nRecent years have seen tremendous progress in utilizing ul trafast light-matter interaction to control the macroscopic properties of quantum materials [1]. Many of the most intriguing effects are based on no nthermal pathways\, with the material (quantum many-body system) being dri ven away from its thermal equilibrium by strong laser pulses. While this h as deepened our understanding of quantum matter far from equilibrium and e nabled us to build bridges to other fields (quantum simulators\, Floquet s tates of matter\, (pre)thermalization\, …)\, there are a number of chall enges: (i) the need for strong lasers\, (ii) heating\, (iii) short lifetim e of light-induced states.\n\nThis has motivated an emergent community of researchers to search for new directions that draw inspiration from the di scoveries in ultrafast materials science and combine them with expertise g leaned from quantum optics\, cavity QED\, polaritonic chemistry\, and nano plasmonics\, creating the new field of "cavity quantum materials“.\n\nIn this Colloquium\, I will provide a personal perspective on this new field and highlight a few of our recent works. Specifically\, I will discuss th e quantum-to-classical crossover of Floquet engineering in correlated syst ems and show how a many-photon classical coherent state can be replaced by a few-photon number state\, provided that one can reach the regime of suf ficiently strong light-matter coupling in a cavity [2]. I will then show h ow the quantum geometry of wavefunctions impacts their light-matter coupli ng\, and how we envision this to be a key ingredient for future light-matt er-based engineering of flat-band (Moiré) materials [3].\n\n[1] A. de la Torre\, D. M. Kennes\, M. Claassen\, S. Gerber\, J. W. McIver\, M. A. Sent ef\, Nonthermal pathways to ultrafast control in quantum materials\, arXiv:2103.14888\n\n[2] M. A. Se ntef\, J. Li\, F. Künzel\, M. Eckstein\, Quantum to classical crossover o f Floquet engineering in correlated quantum systems\, Phys. Rev. Research 2\, 033033 (2020) [3] G. E. Topp\, C. J. Eckhardt\, D. M. Kennes\, M. A. S entef\, P. Törmä\, Light-matter coupling and quantum geometry in moiré materials\, arXiv:2103.04967\n LOCATION:https://researchseminars.org/talk/VSFLRC/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Jonathan Simon (University of Chicago) DTSTART:20210512T171500Z DTEND:20210512T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/12 DESCRIPTION:Title: When Photons Self-Organize: Making Matter from Light\nby Jonathan Simo n (University of Chicago) as part of VSF Long Range Colloquium\n\nAbstract : TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Giuseppe Carleo (EPFL Lausanne) DTSTART:20210526T171500Z DTEND:20210526T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/13 DESCRIPTION:by Giuseppe Carleo (EPFL Lausanne) as part of VSF Long Range C olloquium\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Richard Kueng DTSTART:20210901T171500Z DTEND:20210901T184500Z DTSTAMP:20260422T225720Z UID:VSFLRC/14 DESCRIPTION:Title: Provably efficient machine learning for quantum many-body problems\nby Richard Kueng as part of VSF Long Range Colloquium\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/VSFLRC/14/ END:VEVENT END:VCALENDAR