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X-WR-CALDESC:Events for CMSA
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211201T100000
DTEND;TZID=America/New_York:20211201T113000
DTSTAMP:20260502T183926
CREATED:20240213T070149Z
LAST-MODIFIED:20240213T070149Z
UID:10002153-1638352800-1638358200@cmsa.fas.harvard.edu
SUMMARY:12/1/21 Quantum Matter in Mathematics and Physics
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/12-1-21-quantum-matter-in-mathematics-and-physics/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211124T103000
DTEND;TZID=America/New_York:20211124T120000
DTSTAMP:20260502T183926
CREATED:20240214T100439Z
LAST-MODIFIED:20240301T084626Z
UID:10002655-1637749800-1637755200@cmsa.fas.harvard.edu
SUMMARY:Multipartitioning topological phases and quantum entanglement
DESCRIPTION:Speaker: Shinsei Ryu (Princeton University) \nTitle: Multipartitioning topological phases and quantum entanglement \nAbstract: We discuss multipartitions of the gapped ground states of (2+1)-dimensional topological liquids into three (or more) spatial regions that are adjacent to each other and meet at points. By considering the reduced density matrix obtained by tracing over a subset of the regions\, we compute various correlation measures\, such as entanglement negativity\, reflected entropy\, and associated spectra. We utilize the bulk-boundary correspondence to achieve such multipartitions and construct the reduced density matrix near the entangling boundaries. We find the fingerprints of topological liquid in these quantities\, such as (universal pieces in) the scaling of the entanglement negativity\, and a non-trivial distribution of the spectrum of the partially transposed density matrix.
URL:https://cmsa.fas.harvard.edu/event/11-24-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-11.24.21-1583x2048-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211124T103000
DTEND;TZID=America/New_York:20211124T120000
DTSTAMP:20260502T183926
CREATED:20240213T065517Z
LAST-MODIFIED:20240213T065517Z
UID:10002141-1637749800-1637755200@cmsa.fas.harvard.edu
SUMMARY:11/24/21 Quantum Matter in Mathematics and Physics
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/11-24-21-quantum-matter-in-mathematics-and-physics/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211118T143000
DTEND;TZID=America/New_York:20211118T160000
DTSTAMP:20260502T183926
CREATED:20240214T100731Z
LAST-MODIFIED:20240301T090528Z
UID:10002657-1637245800-1637251200@cmsa.fas.harvard.edu
SUMMARY:Exact Eigenstates in Non-Integrable Systems: A violation of the ETH
DESCRIPTION:Speaker: B. Andrei Bernevig (Princeton University) \nTitle: Exact Eigenstates in Non-Integrable Systems: A violation of the ETH \nAbstract: We find that several non-integrable systems exhibit some exact eigenstates that span the energy spectrum from lowest to the highest state. In the AKLT Hamiltonian and in several others “special” non-integrable models\, we are able to obtain the analytic expression of states exactly and to compute their entanglement spectrum and entropy to show that they violate the eigenstate thermalization hypothesis. This represented the first example of ETH violation in a non-integrable system; these types of states have gained notoriety since then as quantum Scars in the context of Rydberg atoms experiments. We furthermore show that the structure of these states\, in most models where they are found is that of an almost spectrum generating algebra which we call Restricted Spectrum Generating Algebra. This includes the (extended) Hubbard model\, as well as some thin-torus limits of Fractional Quantum Hall states. Yet in other examples\, such as the recently found chiral non-linear Luttinger liquid\, their structure is more complicated and not understood.
URL:https://cmsa.fas.harvard.edu/event/11-18-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Quantum-Matter-in-Mathematics-and-Physics-11.18.21-1583x2048-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211118T143000
DTEND;TZID=America/New_York:20211118T160000
DTSTAMP:20260502T183926
CREATED:20240213T064124Z
LAST-MODIFIED:20240213T064401Z
UID:10002122-1637245800-1637251200@cmsa.fas.harvard.edu
SUMMARY:11/18/21 Quantum Matter in Mathematics and Physics
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/11-18-21-quantum-matter-in-mathematics-and-physics/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211116T150000
DTEND;TZID=America/New_York:20211116T163000
DTSTAMP:20260502T183926
CREATED:20240214T101038Z
LAST-MODIFIED:20240301T090706Z
UID:10002660-1637074800-1637080200@cmsa.fas.harvard.edu
SUMMARY:Quantum Geometric Aspects of Chiral Twisted Graphene Models
DESCRIPTION:Speaker: Jie Wang (Simons Foundation) \nTitle: Quantum Geometric Aspects of Chiral Twisted Graphene Models \nAbstract: “Moire” materials produced by stacking monolayers with small relative twist angles are of intense current interest for the range of correlated electron phenomena they exhibit. The quench of the kinetic energy means that the interacting physics is controlled by the interplay between the interaction scale and intrinsic quantum geometries of the flat band states\, in particular the Berry curvature and the Fubini-Study metric\, which are in general spatially non-uniform. We show that the analytical solution of the twisted bilayer graphene wavefunction in the chiral limit has a special band geometry\, endowing the Brillouin zone with a complex structure. This talk focus on the origin of the momentum space complex structure\, concrete models that realize it\, and its implications to electron-electron interactions. We first show the momentum space complex structure in Chern number C=1 flatbands implies the Bloch wavefunction to exhibit an exact correspondence to the lowest Landau level in the dual momentum space [2]. We present a generalization of the Haldane pseudopotential concept to deal with interacting problems in these bands and discuss experimental implications [2]. We also present an analytically solvable multi-layer generalized chiral graphene model\, which exhibits arbitrarily high Chern number and ideal quantum geometries [3]. Numerical studies of interacting particles indicate model fractional Chern insulators without Landau level analogues\, characterized by exact degeneracies and infinite particle entanglement spectra gaps [3]. References: \n[1] Jie Wang\, Yunqin Zheng\, Andrew J. Millis\, Jennifer Cano (Phys. Rev. Research 3\, 023155)\n[2] Jie Wang\, Jennifer Cano\, Andrew J. Millis\, Zhao Liu\, Bo Yang (arXiv: 2105.07491\, to appear in PRL)\n[3] Jie Wang\, Zhao Liu (arXiv: 2109.10325)
URL:https://cmsa.fas.harvard.edu/event/11-16-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211116T150000
DTEND;TZID=America/New_York:20211116T163000
DTSTAMP:20260502T183926
CREATED:20240213T064804Z
LAST-MODIFIED:20240213T064804Z
UID:10002130-1637074800-1637080200@cmsa.fas.harvard.edu
SUMMARY:11/16/21 Quantum Matter in Mathematics and Physics
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/11-16-21-quantum-matter-in-mathematics-and-physics/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211112T143000
DTEND;TZID=America/New_York:20211112T160000
DTSTAMP:20260502T183926
CREATED:20240214T101408Z
LAST-MODIFIED:20240301T090838Z
UID:10002663-1636727400-1636732800@cmsa.fas.harvard.edu
SUMMARY:A degeneracy bound for homogeneous topological order
DESCRIPTION:Speaker: Jeongwan Haah (Microsoft) \nTitle: A degeneracy bound for homogeneous topological order
URL:https://cmsa.fas.harvard.edu/event/11-12-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211104T103000
DTEND;TZID=America/New_York:20211104T120000
DTSTAMP:20260502T183926
CREATED:20240214T101922Z
LAST-MODIFIED:20240301T091041Z
UID:10002665-1636021800-1636027200@cmsa.fas.harvard.edu
SUMMARY:Fusion Category Symmetries in Quantum Field Theory
DESCRIPTION:Speaker: Yifan Wang (NYU) \nTitle: Fusion Category Symmetries in Quantum Field Theory \nAbstract: Topological defects provide a modern perspective on symmetries in quantum field theory. They generalize the familiar inverti \n \nble symmetries described by groups to non-invertible symmetries described by fusion categories. Such generalized symmetries are ubiquitous in quantum field theory and provide new constraints on renormalization group flows and the IR phase diagram. In this talk I’ll review some recent progress in identifying and understanding fusion category symmetries in 1+1d conformal field theories. Time permitting\, I’ll also comment on higher dimensional generalizations.
URL:https://cmsa.fas.harvard.edu/event/11-4-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211103T140000
DTEND;TZID=America/New_York:20211103T153000
DTSTAMP:20260502T183926
CREATED:20240214T102259Z
LAST-MODIFIED:20240301T091205Z
UID:10002667-1635948000-1635953400@cmsa.fas.harvard.edu
SUMMARY:Non-Invertible Duality Defects in 3+1 Dimensions
DESCRIPTION:Speaker: Clay Cordova (U Chicago) \nTitle: Non-Invertible Duality Defects in 3+1 Dimensions \nAbstract:  For any quantum system invariant under gauging a higher-form global symmetry\, we construct a non-invertible topological defect by gauging in only half of spacetime. This generalizes the Kramers-Wannier duality line in 1+1 dimensions to higher spacetime dimensions. We focus on the case of a one-form symmetry in 3+1 dimensions and determine the fusion rule. From modular invariance and a direct analysis of one-form symmetry-protected topological phases\, we show that the existence of certain kinds of duality defects is intrinsically incompatible with a trivially gapped phase. By further assuming time-reversal symmetry\, we find that the presence of certain duality defects implies that the low-energy phase has to be gapless unless the one-form symmetry is spontaneously broken. We give an explicit realization of this duality defect in the free Maxwell theory where the duality defect is realized by a Chern-Simons coupling between the gauge fields from the two sides.
URL:https://cmsa.fas.harvard.edu/event/11-3-3021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211029T120000
DTEND;TZID=America/New_York:20211029T130000
DTSTAMP:20260502T183926
CREATED:20240301T091725Z
LAST-MODIFIED:20240301T091725Z
UID:10002890-1635508800-1635512400@cmsa.fas.harvard.edu
SUMMARY:Integrability and chaos of 1+1d chiral edge states
DESCRIPTION:Speaker: Biao Lian (Princeton) \nTitle: Integrability and chaos of 1+1d chiral edge states \nAbstract: I will talk about the integrability and chaos of 1+1d interacting chiral edge states\, which may arise on the edge of 2+1d topological phases. We show that integrable chiral Luttinger liquid is not always a good low energy description of the edge states\, and marginal interactions can significantly affect their spectrum and integrability. We first study N identical chiral Majorana fermion modes with random 4-fermion interactions\, where we show that the system undergoes a transition from integrable to quantum chaotic as N increases. The large N limit defines a chiral SYK model where the Lyapunov exponent in the out-of-time-ordered correlation can be solved analytically. I will also present a chiral SY model consisting of N interacting SU(M)_1 WZW models\, which host anyons and exhibits similar quantum chaos for Abelian anyons. Lastly\, I will talk about the analytical and numerical study of the 4/3 FQH edge theory\, which shows unusual behavior in its integrability.
URL:https://cmsa.fas.harvard.edu/event/10-29-2021-quantum-matter-in-mathematics-and-physics-2/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211029T120000
DTEND;TZID=America/New_York:20211029T130000
DTSTAMP:20260502T183926
CREATED:20240214T102641Z
LAST-MODIFIED:20240301T091452Z
UID:10002670-1635508800-1635512400@cmsa.fas.harvard.edu
SUMMARY:Anomaly resolution via decomposition
DESCRIPTION:Speaker: Eric Sharpe (Virginia Tech) \nTitle: Anomaly resolution via decomposition \nAbstract: In this talk we will discuss a method of anomaly resolution due to Wang-Wen-Witten in the special case of (1+1) dimensional theories. Briefly\, for our purposes\, Wang-Wen-Witten argued that an ill-defined anomalous orbifold [X/G] could be resolved by extending G to a larger group and adding suitable phases.  We analyze this process from the perspective of decomposition\, a property of (1+1)-dimensional theories with “one-form symmetries” first described in 2006.  Examples of such theories include orbifolds with trivially-acting subgroups\, of which the extensions of [X/G] are examples.  After a review of decomposition\, we will see that decomposition implies that in (1+1) dimensions\, the Wang-Wen-Witten procedure results in orbifolds that are equivalent to disjoint unions of orbifolds of X by explicitly nonanomalous subgroups of G.
URL:https://cmsa.fas.harvard.edu/event/10-29-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211021T153000
DTEND;TZID=America/New_York:20211021T170000
DTSTAMP:20260502T183926
CREATED:20240214T102900Z
LAST-MODIFIED:20240301T091902Z
UID:10002672-1634830200-1634835600@cmsa.fas.harvard.edu
SUMMARY:Electric-magnetic duality and the Geometric Langlands duality
DESCRIPTION:Title: Electric-magnetic duality and the Geometric Langlands duality \nAbstract: I will give a pedagogical review of the connection between electric-magnetic duality and the Geometric Langlands duality.
URL:https://cmsa.fas.harvard.edu/event/10-21-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211007T203000
DTEND;TZID=America/New_York:20211007T220000
DTSTAMP:20260502T183926
CREATED:20240301T093101Z
LAST-MODIFIED:20240301T093101Z
UID:10002891-1633638600-1633644000@cmsa.fas.harvard.edu
SUMMARY:UV/IR and Effective Field Theory
DESCRIPTION:Speaker: Nima Arkani-Hamed (IAS Princeton) \nTitle: UV/IR and Effective Field Theory
URL:https://cmsa.fas.harvard.edu/event/10-7-2021-quantum-matter-in-mathematics-and-physics-2/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211007T115400
DTEND;TZID=America/New_York:20211007T135400
DTSTAMP:20260502T183926
CREATED:20240214T090253Z
LAST-MODIFIED:20240301T092837Z
UID:10002604-1633607640-1633614840@cmsa.fas.harvard.edu
SUMMARY:A tour of categorical symmetry
DESCRIPTION:Title: A tour of categorical symmetry \nAbstract: I will discuss some perspectives on symmetry coming from the study of topological defects in quantum field theory. I will argue that we should take topological defects themselves to define the symmetries of QFT. This gives us a view of the “category of QFTs”. I will describe some examples of these “categorical symmetries”\, their applications\, and some open problems.
URL:https://cmsa.fas.harvard.edu/event/10-7-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211006T114900
DTEND;TZID=America/New_York:20211006T134900
DTSTAMP:20260502T183926
CREATED:20240214T090718Z
LAST-MODIFIED:20240301T093241Z
UID:10002606-1633520940-1633528140@cmsa.fas.harvard.edu
SUMMARY:Line defects in CFTs: Renormalization group flows and semiclassical limits
DESCRIPTION:Title: Line defects in CFTs: Renormalization group flows and semiclassical limits \nAbstract: I will discuss line defects in d-dimensional Conformal Field Theories (CFTs). In the first part of the talk\, I will argue that the ambient CFT places nontrivial constraints on Renormalization Group (RG) flows on such line defects. I will show that the flow on line defects is consequently irreversible and furthermore a canonical decreasing entropy function exists. This construction generalizes the g theorem to line defects in arbitrary dimensions.  In the second part of the talk\, I will present some applications. In particular\, I will discuss impurities with large isospin S for some O(3) symmetric theories in the epsilon expansion.  For sufficiently large S diagrammatic perturbation theory breaks down\, and these are studied in a semiclassical expansion at fixed epsilon S.
URL:https://cmsa.fas.harvard.edu/event/10-6-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210929T114800
DTEND;TZID=America/New_York:20210929T134800
DTSTAMP:20260502T183926
CREATED:20240214T090955Z
LAST-MODIFIED:20240301T093415Z
UID:10002610-1632916080-1632923280@cmsa.fas.harvard.edu
SUMMARY:Oscillations in the thermal conductivity of a spin liquid*
DESCRIPTION:Title: Oscillations in the thermal conductivity of a spin liquid* \nAbstract: The layered honeycomb magnet alpha-RuCl3 orders below 7 K in a zigzag phase in zero field. An in-plane magnetic field H||a suppresses the zigzag order at 7 Tesla\, leaving a spin-disordered phase widely believed to be a quantum spin liquid (QSL) that extends to ~12 T. We have observed oscillations in the longitudinal thermal conductivity Kxx vs. H from 0.4 to 4 K. The oscillations are periodic in 1/H (with a break-in-slope at 7 T). The amplitude function is maximal in the QSL phase (7 –11.5 T). I will describe a benchmark for crystalline disorder\, the reproducibility and intrinsic nature of the oscillations\, and discuss implications for the QSL state. I will also show detailed data on the thermal Hall conductivity Kxy measured from 0.4 K to 10 K and comment on recent half-quantization results. \n*Czajka et al.\, Nature Physics 17\, 915 (2021). \nCollaborators: Czajka\, Gao\, Hirschberger\, Lampen Kelley\, Banerjee\, Yan\, Mandrus and Nagler.
URL:https://cmsa.fas.harvard.edu/event/9-29-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210923T114700
DTEND;TZID=America/New_York:20210923T134700
DTSTAMP:20260502T183926
CREATED:20240214T091227Z
LAST-MODIFIED:20240301T093540Z
UID:10002612-1632397620-1632404820@cmsa.fas.harvard.edu
SUMMARY:Applications of instantons\, sphalerons and instanton-dyons in QCD
DESCRIPTION:Title: Applications of instantons\, sphalerons and instanton-dyons in QCD \nAbstract: I start with a general map of gauge topology\, including monopoles\, instantons and instanton-dyons. Then comes reminder of the “topological landscape”\, the minimal energy gauge field configurations\, as a function of Chern-Simons number Ncs and r.m.s. size. It includes “valleys” at integer Ncs separated by mountain ridges. The meaning of instantons\, instanton-antiinstanton “streamlines” or thimbles\, and sphalerons are reminded\, together with some proposal to produce sphalerons at LHC and RHIC. \nApplications of instanton ensembles\, as a model of QCD vacuum\, are mostly related to their fermionic zero modes  and t’Hooft effective Lagrangian\, which explains explicit and spontaneous breaking of chiral symmetries. Recent applications are related with hadronic wave functions\, at rest and in the light front (LFWFs). Two application would be spin-dependent forces and the so called “flavor asymmetry of antiquark sea” of the nucleons. At temperatures comparable to deconfinement transition\, instantons get split into constituents called instanton-dyons. Studies of their ensemble explains both deconfinement and chiral transitions\, in ordinary and deformed QCD.
URL:https://cmsa.fas.harvard.edu/event/9-23-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210922T113300
DTEND;TZID=America/New_York:20210922T133300
DTSTAMP:20260502T183926
CREATED:20240214T091602Z
LAST-MODIFIED:20240301T094449Z
UID:10002615-1632310380-1632317580@cmsa.fas.harvard.edu
SUMMARY:Symmetry types in QFT and the CRT theorem
DESCRIPTION:Title: Symmetry types in QFT and the CRT theorem \nAbstract: I will discuss ideas around symmetry and Wick rotation contained in joint work with Mike Hopkins (https://arxiv.org/abs/1604.06527). This includes general symmetry types for relativistic field theories and their Wick rotation.  I will then indicate how the basic CRT theorem works for general symmetry types\, focusing on the case of the pin groups.  In particular\, I expand on a subtlety first flagged by Greaves-Thomas.
URL:https://cmsa.fas.harvard.edu/event/9-22-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210917T185400
DTEND;TZID=America/New_York:20210917T195400
DTSTAMP:20260502T183926
CREATED:20240214T091836Z
LAST-MODIFIED:20240301T094616Z
UID:10002617-1631904840-1631908440@cmsa.fas.harvard.edu
SUMMARY:Strong Coupling Theory of Magic-Angle Graphene: A Pedagogical Introduction
DESCRIPTION:Title: Strong Coupling Theory of Magic-Angle Graphene: A Pedagogical Introduction \nAbstract: In this talk\, I will review a recently developed strong coupling theory of magic-angle twisted bilayer graphene. An advantage of this approach is that a single formulation can capture both the insulating and superconducting states\, and with a few simplifying assumptions\, can be treated analytically. I begin by reviewing the electronic structure of magic angle graphene’s flat bands\, in a limit that exposes their peculiar band topology and geometry. I will show how similarities between the flat bands and the lowest Landau level can provide valuable insights into the effect of interactions and form the basis for an analytic treatment of the problem. At integer fillings\, this approach points to flavor ordered insulators\, which can be captured by a sigma-model in its ordered phase. Remarkably\, topological textures of the sigma model carry electric charge which enables the same theory to describe the doped phases away from integer filling. I will show how this approach can lead to superconductivity on disordering the sigma model\, and estimate the Tc for the superconductor. I will highlight the important role played by an effective super-exchange coupling both in pairing and in setting the effective mass of Cooper pairs. At the end\, I will show how this theory provides criteria to predict which multilayer graphene stacks are expected to superconduct including the recently discovered alternating twist trilayer platform.
URL:https://cmsa.fas.harvard.edu/event/9-17-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210916T184700
DTEND;TZID=America/New_York:20210916T194700
DTSTAMP:20260502T183926
CREATED:20240214T092053Z
LAST-MODIFIED:20240301T094752Z
UID:10002619-1631818020-1631821620@cmsa.fas.harvard.edu
SUMMARY:The Hilbert Space of large N Chern-Simons matter theories
DESCRIPTION:Title: The Hilbert Space of large N Chern-Simons matter theories \nAbstract: We demonstrate that all known formulae for the thermal partition function for large N Chern Simons matter theory admit a simple Hilbert Space interpretation. In each case this quantity equals the partition function of an associated ungauged large $N$ matter theory with a particular local Lagrangian with one additional element: the Fock Space of this associated theory is projected down to the subspace of its WZW singlets. This projection\, in particular\,  implies the previously encountered `Bosonic Exclusion Principle’\, namely that no single particle state can be occupied by more than $k_B$ particles ($k_B$ is the Chern Simons level). Unlike its Gauss Law counterpart\, the WZW constraint does not trivialize in the large volume limit. However thermodynamics does simplify in this limit;  the final partition function reduces to a product of partition functions associated with each single particle state. These individual single particle state partition functions are a one parameter generalizations of their free boson and free fermion counterparts\, and reduce to the later at extreme values of the ‘t Hooft coupling. At generic values of the rank and the level the occupation statistics of each energy level is given by a $q$ deformation of the usual free formulae of Bose and Fermi statistics.
URL:https://cmsa.fas.harvard.edu/event/9-16-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210915T184600
DTEND;TZID=America/New_York:20210915T194600
DTSTAMP:20260502T183926
CREATED:20240214T092313Z
LAST-MODIFIED:20240301T094948Z
UID:10002623-1631731560-1631735160@cmsa.fas.harvard.edu
SUMMARY:Three-particle mechanism for pairing and superconductivity
DESCRIPTION:Title: Three-particle mechanism for pairing and superconductivity \nAbstract: I will present a new mechanism and an exact theory of electron pairing due to repulsive interaction in doped insulators. When the kinetic energy is small\, the dynamics of adjacent electrons on the lattice is strongly correlated. By developing a controlled kinetic energy expansion\, I will show that two doped charges can attract and form a bound state\, despite and because of the underlying repulsion. This attraction by repulsion is enabled by the virtual excitation of a third electron in the filled band. This three-particle pairing mechanism leads to a variety of novel phenomena at finite doping\, including spin-triplet superconductivity\, pair density wave\, BCS-BEC crossover and Feshbach resonance involving “trimers”. Possible realizations in moire materials\, ZrNCl and WTe2 will be discussed. \n[1] V. Crepel and L. Fu\, Science Advances 7\, eabh2233 (2021)\n[2] V. Crepel and L. Fu\, arXiv:2103.12060\n[3] K. Slagle and L. Fu\,  Phys. Rev. B 102\, 235423 (2020)
URL:https://cmsa.fas.harvard.edu/event/9-15-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210910T184400
DTEND;TZID=America/New_York:20210910T194400
DTSTAMP:20260502T183926
CREATED:20240214T092532Z
LAST-MODIFIED:20240301T095315Z
UID:10002624-1631299440-1631303040@cmsa.fas.harvard.edu
SUMMARY:More Exact Results in Gauge Theories: Confinement and Chiral Symmetry Breaking
DESCRIPTION:Title: More Exact Results in Gauge Theories: Confinement and Chiral Symmetry Breaking \nAbstract: In this follow-up to Hitoshi Murayama’s talk “Some Exact Results in QCD-like and Chiral Gauge Theories”\, I present a detailed analysis of the phases of $SO(N_c)$ gauge theory.\nStarting with supersymmetric $SO(N_c)$ with $N_F$ flavors\, we extrapolate to the non-supersymmetric limit using anomaly-mediated supersymmetry breaking (AMSB). Interestingly\, the abelian Coulomb and free magnetic phases do not survive supersymmetry breaking and collapse to a confining phase. This provided one of the first demonstrations of true confinement with chiral symmetry breaking in a non-SUSY theory.
URL:https://cmsa.fas.harvard.edu/event/9-10-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210909T183800
DTEND;TZID=America/New_York:20210909T193800
DTSTAMP:20260502T183926
CREATED:20240214T092815Z
LAST-MODIFIED:20240301T095523Z
UID:10002628-1631212680-1631216280@cmsa.fas.harvard.edu
SUMMARY:Quantum gravity from quantum matter
DESCRIPTION:Title: Quantum gravity from quantum matter \nAbstract: We present a model of quantum gravity in which dimension\, topology and geometry of spacetime are collective dynamical variables that describe the pattern of entanglement of underlying quantum matter. As spacetimes with arbitrary dimensions can emerge\, the gauge symmetry is generalized to a group that includes diffeomorphisms in general dimensions. The gauge symmetry obeys a first-class constraint operator algebra\, and is reduced to a generalized hypersurface deformation algebra in states that exhibit classical spacetimes. In the semi-classical limit\, we find a saddle-point solution that describes a series of (3+1)-dimensional de Sitter-like spacetimes with the Lorentzian signature bridged by Euclidean spaces in between.
URL:https://cmsa.fas.harvard.edu/event/9-9-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210908T183700
DTEND;TZID=America/New_York:20210908T193700
DTSTAMP:20260502T183926
CREATED:20240214T093235Z
LAST-MODIFIED:20240301T095658Z
UID:10002632-1631126220-1631129820@cmsa.fas.harvard.edu
SUMMARY:Cornering the universal shape of fluctuations and entanglement
DESCRIPTION:Title: Cornering the universal shape of fluctuations and entanglement \nAbstract: Understanding the fluctuations of observables is one of the main goals in physics. We investigate such fluctuations when a subregion of the full system can be observed\, focusing on geometries with corners. We report that the dependence on the opening angle is super-universal: up to a numerical prefactor\, this function does not depend on anything\, provided the system under study is uniform\, isotropic\, and correlations do not decay too slowly. The prefactor contains important physical information: we show in particular that it gives access to the long-wavelength limit of the structure factor. We illustrate our findings with several examples: classical fluids\, fractional quantum Hall (FQH) states\, scale invariant quantum critical theories\, and metals. Finally\, we discuss connections with the entanglement entropy\, including new results for Laughlin FQH states. \nRef: arXiv:2102.06223
URL:https://cmsa.fas.harvard.edu/event/9-8-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210902T183400
DTEND;TZID=America/New_York:20210902T193400
DTSTAMP:20260502T183926
CREATED:20240214T093431Z
LAST-MODIFIED:20240301T095944Z
UID:10002634-1630607640-1630611240@cmsa.fas.harvard.edu
SUMMARY:Exotic quantum matter: From lattice gauge theory to hyperbolic lattices
DESCRIPTION:Title: Exotic quantum matter: From lattice gauge theory to hyperbolic lattices \nAbstract: This talk\, in two parts\, will discuss two (unrelated) instances of exotic quantum matter. In the first part\, I will discuss quantum critical points describing possible transitions out of the Dirac spin liquid\, towards either symmetry-breaking phases or topologically ordered spin liquids. I will also comment on the role of instanton zero modes for symmetry breaking in parton gauge theories. In the second part\, I will propose an extension of Bloch band theory to hyperbolic lattices\, such as those recently realized in circuit QED experiments\, based on ideas from algebraic geometry and Riemann surface theory.
URL:https://cmsa.fas.harvard.edu/event/9-2-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210901T183100
DTEND;TZID=America/New_York:20210901T193100
DTSTAMP:20260502T183926
CREATED:20240214T093606Z
LAST-MODIFIED:20240301T100331Z
UID:10002639-1630521060-1630524660@cmsa.fas.harvard.edu
SUMMARY:Naturalness and muon anomalous magnetic moment
DESCRIPTION:Title: Naturalness and muon anomalous magnetic moment \nAbstract: We study a model for explaining the apparent deviation of the muon anomalous magnetic moment\, (g-2)\, from the Standard Model expectation. There are no new scalars and hence no new hierarchy puzzles beyond those associated with the Standard model Higgs; the only new particles that are relevant for (g-2) are vector-like singlet and doublet leptons. Interestingly\, this simple model provides a calculable example violating the Wilsonian notion of naturalness: despite the absence of any symmetries prohibiting its generation\, the coefficient of the naively leading dimension-six operator for (g−2) vanishes at one-loop. While effective field theorists interpret this either as a surprising UV cancellation of power divergences\, or as a delicate cancellation between matching UV and calculable IR corrections to (g−2) from parametrically separated scales\, there is a simple explanation in the full theory: the loop integrand is a total derivative of a function vanishing in both the deep UV and IR. The leading contribution to (g−2) arises from dimension-eight operators\, and thus the required masses of new fermions are lower than naively expected\, with a sizable portion of parameter space already covered by direct searches at the LHC. All of the the viable parameter can be probed by the LHC and planned future colliders.
URL:https://cmsa.fas.harvard.edu/event/9-1-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210729T103000
DTEND;TZID=America/New_York:20210729T120000
DTSTAMP:20260502T183926
CREATED:20240213T085639Z
LAST-MODIFIED:20240213T085639Z
UID:10002273-1627554600-1627560000@cmsa.fas.harvard.edu
SUMMARY:The nu=5/2 enigma: Recent insights from theory and experiment
DESCRIPTION:peaker: Ady Stern & David Mross (Weizmann) \nSpeaker: Ady Stern & David Mross (Weizmann \nTitle: The nu=5/2 enigma: Recent insights from theory and experiment \nAbstract: Non-Abelian phases of matter have long inspired quantum physicists across various disciplines. The strongest experimental evidence of such a phase arises in quantum Hall systems at the filling factor 5/2 but conflicts with decades of numerical works. We will briefly introduce the 5/2 plateau and explain some of the key obstacles to identifying its topological order. We will then describe recent experimental and theoretical progress\, including a proposal for resolving the 5/2 enigma based on electrical conductance measurements.
URL:https://cmsa.fas.harvard.edu/event/the-nu5-2-enigma-recent-insights-from-theory-and-experiment/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210722T080000
DTEND;TZID=America/New_York:20210722T093000
DTSTAMP:20260502T183926
CREATED:20240213T085228Z
LAST-MODIFIED:20240213T085228Z
UID:10002266-1626940800-1626946200@cmsa.fas.harvard.edu
SUMMARY:7/22/2021 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/7-22-2021-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210721T103000
DTEND;TZID=America/New_York:20210721T120000
DTSTAMP:20260502T183926
CREATED:20240213T085105Z
LAST-MODIFIED:20240213T085105Z
UID:10002262-1626863400-1626868800@cmsa.fas.harvard.edu
SUMMARY:7/21/2021 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/7-21-2021-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Quantum Matter
END:VEVENT
END:VCALENDAR