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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220921T090000
DTEND;TZID=America/New_York:20220921T100000
DTSTAMP:20260503T235217
CREATED:20230705T064901Z
LAST-MODIFIED:20240229T110819Z
UID:10001142-1663750800-1663754400@cmsa.fas.harvard.edu
SUMMARY:Geometric test for topological states of matter
DESCRIPTION:Topological Quantum Matter Seminar\nSpeaker: Semyon Klevtsov\, University of Strasbourg \nTitle: Geometric test for topological states of matter \nAbstract: We generalize the flux insertion argument due to Laughlin\, Niu-Thouless-Tao-Wu\, and Avron-Seiler-Zograf to the case of fractional quantum Hall states on a higher-genus surface. We propose this setting as a test to characterise the robustness\, or topologicity\, of the quantum state of matter and apply our test to the Laughlin states. Laughlin states form a vector bundle\, the Laughlin bundle\, over the Jacobian – the space of Aharonov-Bohm fluxes through the holes of the surface. The rank of the Laughlin bundle is the \ndegeneracy of Laughlin states or\, in presence of quasiholes\, the dimension of the corresponding full many-body Hilbert space; its slope\, which is the first Chern class divided by the rank\, is the Hall conductance. We compute the rank and all the Chern classes of Laughlin bundles for any genus and any number of quasiholes\, settling\, in particular\, the Wen-Niu conjecture. Then we show that Laughlin bundles with non-localized quasiholes are not projectively flat and that the Hall current is precisely quantized only for the states with localized quasiholes. Hence our test distinguishes these states from the full many-body Hilbert space. Based on joint work with Dimitri Zvonkine (CNRS\, University of Paris-Versaille). \n 
URL:https://cmsa.fas.harvard.edu/event/geometric-test-for-topological-states-of-matter/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-09.21.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220921T110000
DTEND;TZID=America/New_York:20220921T120000
DTSTAMP:20260503T235217
CREATED:20230824T174949Z
LAST-MODIFIED:20240229T104238Z
UID:10001312-1663758000-1663761600@cmsa.fas.harvard.edu
SUMMARY:Limit and potential of adaptive immunity
DESCRIPTION:Active Matter Seminar\n\nSpeaker: Shenshen Wang\, UCLA\n\n\nTitle:  Limit and potential of adaptive immunity\n\nAbstract: The adaptive immune system is able to learn from past experiences to better fit an\nunforeseen future. This is made possible by a diverse and dynamic repertoire of cells\nexpressing unique antigen receptors and capable of rapid Darwinian evolution within an\nindividual. However\, naturally occurring immune responses exhibit limits in efficacy\,\nspeed and capacity to adapt to novel challenges. In this talk\, I will discuss theoretical\nframeworks we developed to (1) explore functional impacts of non-equilibrium antigen\nrecognition\, and (2) identify conditions under which natural selection acting local in time\ncan find adaptable solutions favorable in the long run\, through exploiting environmental\nvariations and functional constraints.
URL:https://cmsa.fas.harvard.edu/event/title-tba/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Active Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Active-Matter-Seminar-09.21.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220921T123000
DTEND;TZID=America/New_York:20220921T133000
DTSTAMP:20260503T235217
CREATED:20240214T114047Z
LAST-MODIFIED:20240502T145616Z
UID:10002705-1663763400-1663767000@cmsa.fas.harvard.edu
SUMMARY:Moduli spaces of graphs
DESCRIPTION:Colloquium\n\nSpeaker: Melody Chan\, Brown\n\nTitle: Moduli spaces of graphs\n\nAbstract: A metric graph is a graph—a finite network of vertices and edges—together with a prescription of a positive real length on each edge. I’ll use the term “moduli space of graphs” to refer to certain combinatorial spaces—think simplicial complexes—that furnish parameter spaces for metric graphs. There are different flavors of spaces depending on some additional choices of decorations on the graphs\, but roughly\, each cell parametrizes all possible metrizations of a fixed combinatorial graph. Many flavors of these moduli spaces have been in circulation for a while\, starting with the work of Culler-Vogtmann in the 1980s on Outer Space. They have also recently played an important role in some recent advances using tropical geometry to study the topology of moduli spaces of curves and other related spaces. These advances give me an excuse to give what I hope will be an accessible introduction to moduli spaces of graphs and their connections with geometry.
URL:https://cmsa.fas.harvard.edu/event/collquium-92122/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-09.21.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220922T103000
DTEND;TZID=America/New_York:20220922T113000
DTSTAMP:20260503T235217
CREATED:20240216T113602Z
LAST-MODIFIED:20240229T110700Z
UID:10002767-1663842600-1663846200@cmsa.fas.harvard.edu
SUMMARY:A scale-critical trapped surface formation criterion for the Einstein-Maxwell system
DESCRIPTION:General Relativity Seminar \n\n\nSpeaker: Nikolaos Athanasiou\n\nTitle: A scale-critical trapped surface formation criterion for the Einstein-Maxwell system\n\nAbstract: Few notions within the realm of mathematical physics succeed in capturing the imagination and inspiring awe as well as that of a black hole. First encountered in the Schwarzschild solution\, discovered a few months after the presentation of the Field Equations of General Relativity at the Prussian Academy of Sciences\, the black hole as a mathematical phenomenon accompanies and prominently features within the history of General Relativity since its inception. In this talk we will lay out a brief history of the question of dynamical black hole formation in General Relativity and discuss a result\, in collaboration with Xinliang An\, on a scale-critical trapped surface formation criterion for the Einstein-Maxwell system.
URL:https://cmsa.fas.harvard.edu/event/a-scale-critical-trapped-surface-formation-criterion-for-the-einstein-maxwell-system/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:General Relativity Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-GR-Seminar-09.22.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220923T043000
DTEND;TZID=America/New_York:20220923T180000
DTSTAMP:20260503T235217
CREATED:20230705T045048Z
LAST-MODIFIED:20231226T164613Z
UID:10000059-1663907400-1663956000@cmsa.fas.harvard.edu
SUMMARY:CMSA/MATH Fall Gathering
DESCRIPTION:CMSA/MATH Fall Gathering \nFriday\, Sep 23\, 2022\n4:30–6:00 pm\n\nAll CMSA and Math affiliates are invited.
URL:https://cmsa.fas.harvard.edu/event/fall_2022/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220923T110000
DTEND;TZID=America/New_York:20220923T120000
DTSTAMP:20260503T235217
CREATED:20240214T105452Z
LAST-MODIFIED:20240301T083553Z
UID:10002685-1663930800-1663934400@cmsa.fas.harvard.edu
SUMMARY:Random determinants\, the elastic manifold\, and landscape complexity beyond invariance
DESCRIPTION:Member Seminar \nSpeaker: Ben McKenna \nTitle: Random determinants\, the elastic manifold\, and landscape complexity beyond invariance \nAbstract: The Kac-Rice formula allows one to study the complexity of high-dimensional Gaussian random functions (meaning asymptotic counts of critical points) via the determinants of large random matrices. We present new results on determinant asymptotics for non-invariant random matrices\, and use them to compute the (annealed) complexity for several types of landscapes. We focus especially on the elastic manifold\, a classical disordered elastic system studied for example by Fisher (1986) in fixed dimension and by Mézard and Parisi (1992) in the high-dimensional limit. We confirm recent formulas of Fyodorov and Le Doussal (2020) on the model in the Mézard-Parisi setting\, identifying the boundary between simple and glassy phases. Joint work with Gérard Ben Arous and Paul Bourgade.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-title-tba/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220926T090000
DTEND;TZID=America/New_York:20220926T103000
DTSTAMP:20260503T235217
CREATED:20240216T113233Z
LAST-MODIFIED:20240229T110730Z
UID:10002766-1664182800-1664188200@cmsa.fas.harvard.edu
SUMMARY:Candidates for Non-Supersymmetric Dualities
DESCRIPTION:Quantum Matter in Mathematics and Physics \nSpeaker: Avner Karasik (University of Cambridge\, UK)\nTitle: Candidates for Non-Supersymmetric Dualities \nAbstract: In the talk I will discuss the possibility and the obstructions of finding non-supersymmetric dualities for 4d gauge theories. I will review consistency conditions based on Weingarten inequalities\, anomalies and large N\, and clarify some subtle points and misconceptions about them. Later I will go over some old and new examples of candidates for non-supersymmetric dualities. The will be based on 2208.07842 \n 
URL:https://cmsa.fas.harvard.edu/event/non-invertible-symmetries-in-nature-2/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-Seminar-09.26.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220928T090000
DTEND;TZID=America/New_York:20220928T100000
DTSTAMP:20260503T235217
CREATED:20230705T072111Z
LAST-MODIFIED:20240216T111812Z
UID:10001141-1664355600-1664359200@cmsa.fas.harvard.edu
SUMMARY:Extracting the quantum Hall conductance from a single bulk wavefunction from the modular flow
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Ruihua Fan\, Harvard University \nTitle: Extracting the quantum Hall conductance from a single bulk wavefunction from the modular flow\n\nAbstract: One question in the study of topological phases is to identify the topological data from the ground state wavefunction without accessing the Hamiltonian. Since local measurement is not enough\, entanglement becomes an indispensable tool. Here\, we use modular Hamiltonian (entanglement Hamiltonian) and modular flow to rephrase previous studies on topological entanglement entropy and motivate a natural generalization\, which we call the entanglement linear response. We will show how it embraces a previous work by Kim&Shi et al on the chiral central charge\, and furthermore\, inspires a new formula for the quantum Hall conductance.\n\nReferences: https://arxiv.org/abs/2206.02823\, https://arxiv.org/abs/2208.11710
URL:https://cmsa.fas.harvard.edu/event/tqm92822/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-09.28.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220928T123000
DTEND;TZID=America/New_York:20220928T133000
DTSTAMP:20260503T235217
CREATED:20230817T172722Z
LAST-MODIFIED:20240229T110654Z
UID:10001265-1664368200-1664371800@cmsa.fas.harvard.edu
SUMMARY:The Tree Property and uncountable cardinals
DESCRIPTION:Colloquium \nSpeaker: Dima Sinapova (Rutgers University) \nTitle: The Tree Property and uncountable cardinals \nAbstract: In the late 19th century Cantor discovered that there are different levels of infinity. More precisely he showed that there is no bijection between the natural numbers and the real numbers\, meaning that the reals are uncountable. He then went on to discover a whole hierarchy of infinite cardinal numbers. It is natural to ask if finitary and countably infinite combinatorial objects have uncountable analogues. It turns out that the answer is yes. \nWe will focus on one such key combinatorial property\, the tree property. A classical result from graph theory (König’s infinity lemma) shows the existence of this property for countable trees. We will discuss what happens in the case of uncountable trees.\n\n 
URL:https://cmsa.fas.harvard.edu/event/collquium-title-tba-2-2/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-09.28.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220928T140000
DTEND;TZID=America/New_York:20220928T150000
DTSTAMP:20260503T235217
CREATED:20230808T184138Z
LAST-MODIFIED:20240214T110335Z
UID:10001211-1664373600-1664377200@cmsa.fas.harvard.edu
SUMMARY:Statistical mechanics of neural networks: From the geometry of high dimensional error landscapes to beating power law neural scaling
DESCRIPTION:New Technologies in Mathematics \nSpeaker: Surya Ganguli\, Stanford University \n\nTitle: Statistical mechanics of neural networks: From the geometry of high dimensional error landscapes to beating power law neural scaling\n\n\n\n\nAbstract: Statistical mechanics and neural network theory have long enjoyed fruitful interactions.  We will review some of our recent work in this area and then focus on two vignettes. First we will analyze the high dimensional geometry of neural network error landscapes that happen to arise as the classical limit of a dissipative many-body quantum optimizer.  In particular\, we will be able to use the Kac-Rice formula and the replica method to calculate the number\, location\, energy levels\, and Hessian eigenspectra of all critical points of any index.  Second we will review recent work on neural power laws\, which reveal that the error of many neural networks falls off as a power law with network size or dataset size.  Such power laws have motivated significant societal investments in large scale model training and data collection efforts.  Inspired by statistical mechanics calculations\, we show both in theory and in practice how we can beat neural power law scaling with respect to dataset size\, sometimes achieving exponential scaling\, by collecting small carefully curated datasets rather than large random ones.\n\n\n\nReferences: Y. Bahri\, J. Kadmon\, J. Pennington\, S. Schoenholz\, J. Sohl-Dickstein\, and S. Ganguli\, Statistical mechanics of deep learning\, Annual Reviews of Condensed Matter Physics\, 2020.\n\nSorscher\, Ben\, Robert Geirhos\, Shashank Shekhar\, Surya Ganguli\, and Ari S. Morcos. 2022. Beyond Neural Scaling Laws: Beating Power Law Scaling via Data Pruning https://arxiv.org/abs/2206.14486 (NeurIPS 2022).
URL:https://cmsa.fas.harvard.edu/event/8303/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-NTM-Seminar-09.28.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220929T103000
DTEND;TZID=America/New_York:20220929T113000
DTSTAMP:20260503T235217
CREATED:20240216T091125Z
LAST-MODIFIED:20240229T111436Z
UID:10002755-1664447400-1664451000@cmsa.fas.harvard.edu
SUMMARY:General-relativistic viscous fluids
DESCRIPTION:General Relativity Seminar \nSpeaker: Marcelo Disconzi\, Vanderbilt University \nTitle: General–relativistic viscous fluids\n\nAbstract: The discovery of the quark-gluon plasma that forms in heavy-ion collision experiments provides a unique opportunity to study the properties of matter under extreme conditions\, as the quark-gluon plasma is the hottest\, smallest\, and densest fluid known to humanity. Studying the quark-gluon plasma also provides a window into the earliest moments of the universe\, since microseconds after the Big Bang the universe was filled with matter in the form of the quark-gluon plasma. For more than two decades\, the community has intensely studied the quark-gluon plasma with the help of a rich interaction between experiments\, theory\, phenomenology\, and numerical simulations. From these investigations\, a coherent picture has emerged\, indicating that the quark-gluon plasma behaves essentially like a relativistic liquid with viscosity. More recently\, state-of-the-art numerical relativity simulations strongly suggested that viscous and dissipative effects can also have non-negligible effects on gravitational waves produced by binary neutron star mergers. But despite the importance of viscous effects for the study of such systems\, a robust and comprehensive theory of relativistic fluids with viscosity is still lacking. This is due\, in part\, to difficulties to preserve causality upon the inclusion of viscous and dissipative effects into theories of relativistic fluids. In this talk\, we will survey the history of the problem and report on a new approach to relativistic viscous fluids that addresses these issues.
URL:https://cmsa.fas.harvard.edu/event/general-relativistic-viscous-fluids/
LOCATION:Virtual
CATEGORIES:General Relativity Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-GR-Seminar-09.29.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220930T093000
DTEND;TZID=America/New_York:20220930T103000
DTSTAMP:20260503T235217
CREATED:20230825T080835Z
LAST-MODIFIED:20240215T093911Z
UID:10001297-1664530200-1664533800@cmsa.fas.harvard.edu
SUMMARY:GLSM\, Homological projective duality and nc resolutions
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker:  Mauricio Romo\, Tsinghua University \nTitle: GLSM\, Homological projective duality and nc resolutions\n\nAbstract: Kuznetsov’s Homological projective duality (HPD) in algebraic geometry is a powerful theorem that allows to extract information about semiorthogonal decompositions of derived categories of certain varieties. I will give a GLSMs perspective based on categories of B-branes. I will focus mostly on the case of Fano (hypersurfaces) manifolds. In general\, for such cases the HPD can be interpreted as a non-commutative (nc) resolution of a compact variety. I will give a physical interpretation of this fact and present some conjectures.
URL:https://cmsa.fas.harvard.edu/event/glsm-homological-projective-duality-and-nc-resolutions/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-09.30.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220930T110000
DTEND;TZID=America/New_York:20220930T120000
DTSTAMP:20260503T235217
CREATED:20240214T105247Z
LAST-MODIFIED:20240301T081921Z
UID:10002683-1664535600-1664539200@cmsa.fas.harvard.edu
SUMMARY:Kahler geometry in twisted materials
DESCRIPTION:Member Seminar \nSpeaker: Jie Wang \nTitle: Kahler geometry in twisted materials \nAbstract: Flatbands are versatile platform for realizing exotic quantum phases due to the enhanced interactions. The canonical example is Landau level where fractional quantum Hall physics exists. Although interaction is strong\, the fractional quantum Hall effect is relatively well understood thanks to its model wavefunction\, exact parent Hamiltonian\, conformal field theory analogous and other exact aspects. In generic flatbands\, the interacting physics is controlled by the interplay between the interaction scale and intrinsic quantum geometries\, in particular the Berry curvature and the Fubini-Study metric\, which are in general spatially non-uniform. It is commonly believed that the non-uniform geometries destroy these exact properties of fractional quantum Hall physics\, making many-body states less stable in flatbands. \nIn this talk\, I will disprove this common belief by showing a large family of flatbands (ideal flatbands) where quantum geometries can be highly non-uniform\, but still exhibit exact properties such as model wavefunctions\, density algebra\, exact parent Hamiltonians. I will discuss both the theory of ideal flatband\, its experimental realization in Dirac materials as well as implications.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-93022/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221004T093000
DTEND;TZID=America/New_York:20221004T110000
DTSTAMP:20260503T235217
CREATED:20240216T090303Z
LAST-MODIFIED:20240813T162619Z
UID:10002752-1664875800-1664881200@cmsa.fas.harvard.edu
SUMMARY:Holomorphic Twists and Confinement in N=1 SYM
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Justin Kulp (Perimeter Institute) \nTitle: Holomorphic Twists and Confinement in N=1 SYM \nAbstract: Supersymmetric QFT’s are of long-standing interest for their high degree of solvability\, phenomenological implications\, and rich connections to mathematics. In my talk\, I will describe how the holomorphic twist isolates the protected quantities which give SUSY QFTs their potency by restricting to the cohomology of one supercharge. I will briefly introduce infinite dimensional symmetry algebras\, generalizing Virasoro and Kac-Moody symmetries\, which emerge. Finally\, I will explain a potential novel UV manifestation of confinement\, dubbed “holomorphic confinement\,” in the example of pure SU(N) super Yang-Mills. Based on arXiv:2207.14321 and 2 forthcoming works with Kasia Budzik\, Davide Gaiotto\, Brian Williams\, Jingxiang Wu\, and Matthew Yu.
URL:https://cmsa.fas.harvard.edu/event/qm_tba/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-Seminar-10.04.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221005T140000
DTEND;TZID=America/New_York:20221005T160000
DTSTAMP:20260503T235217
CREATED:20230808T184616Z
LAST-MODIFIED:20240214T110102Z
UID:10001212-1664978400-1664985600@cmsa.fas.harvard.edu
SUMMARY:Minerva: Solving Quantitative Reasoning Problems with Language Models
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Guy Gur-Ari\, Google Research \nTitle: Minerva: Solving Quantitative Reasoning Problems with Language Models \nAbstract: Quantitative reasoning tasks which can involve mathematics\, science\, and programming are often challenging for machine learning models in general and for language models in particular. We show that transformer-based language models obtain significantly better performance on math and science questions when trained in an unsupervised way on a large\, math-focused dataset. Performance can be further improved using prompting and sampling techniques including chain-of-thought and majority voting. Minerva\, a model that combines these techniques\, achieves SOTA on several math and science benchmarks. I will describe the model\, its capabilities and limitations.
URL:https://cmsa.fas.harvard.edu/event/minerva-solving-quantitative-reasoning-problems-with-language-models/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/10.05.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221005T160000
DTEND;TZID=America/New_York:20221005T170000
DTSTAMP:20260503T235217
CREATED:20230817T173038Z
LAST-MODIFIED:20240229T110447Z
UID:10001266-1664985600-1664989200@cmsa.fas.harvard.edu
SUMMARY:Quantum statistical mechanics of charged black holes and strange metals
DESCRIPTION:Colloquium \nPlease note this colloquium will be held at a special time:  4:00-5:00 pm. \nSpeaker: Subir Sachdev (Harvard) \nTitle: Quantum statistical mechanics of charged black holes and strange metals\n\nAbstract: The Sachdev-Ye-Kitaev model was introduced as a toy model of interacting fermions without any particle-like excitations. I will describe how this toy model yields the universal low energy quantum theory of generic charged black holes in asymptotically 3+1 dimensional Minkowski space. I will also discuss how extensions of the SYK model yield a realistic theory of the strange metal phase of correlated electron systems.\n\n\nSlides: cmsa22
URL:https://cmsa.fas.harvard.edu/event/colloquium_10522/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.05.22-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221006T103000
DTEND;TZID=America/New_York:20221006T233000
DTSTAMP:20260503T235217
CREATED:20240215T092242Z
LAST-MODIFIED:20240229T092649Z
UID:10002715-1665052200-1665099000@cmsa.fas.harvard.edu
SUMMARY:Duality in Einstein’s Gravity
DESCRIPTION:General Relativity Seminar \nSpeaker: Uri Kol\, CMSA \n\nTitle: Duality in Einstein’s Gravity \nAbstract: Electric-Magnetic duality has been a key feature behind our understanding of Quantum Field Theory for over a century. In this talk I will describe a similar property in Einstein’s gravity. The gravitational duality reveals\, in turn\, a wide range of new IR phenomena\, including aspects of the double copy for scattering amplitudes\, asymptotic symmetries and more.
URL:https://cmsa.fas.harvard.edu/event/gr_10622/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:General Relativity Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221007T093000
DTEND;TZID=America/New_York:20221007T103000
DTSTAMP:20260503T235217
CREATED:20230825T081109Z
LAST-MODIFIED:20240215T093620Z
UID:10001298-1665135000-1665138600@cmsa.fas.harvard.edu
SUMMARY:Scattering Diagrams from Holomorphic Discs in Log Calabi-Yau Surfaces
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Sam Bardwell-Evans\, Boston University\n\n\nTitle: Scattering Diagrams from Holomorphic Discs in Log Calabi-Yau Surfaces\n\nAbstract: In this talk\, we construct special Lagrangian fibrations for log Calabi-Yau surfaces and scattering diagrams from Lagrangian Floer theory of the fibers. These scattering diagrams recover the algebro-geometric scattering diagrams of Gross-Pandharipande-Siebert and Gross-Hacking-Keel. The argument relies on a holomorphic/tropical disc correspondence to control the behavior of holomorphic discs\, allowing us to relate open Gromov-Witten invariants to log Gromov-Witten invariants. This talk is based on joint work with Man-Wai Mandy Cheung\, Hansol Hong\, and Yu-Shen Lin.
URL:https://cmsa.fas.harvard.edu/event/agst/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-10.07.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221007T110000
DTEND;TZID=America/New_York:20221007T120000
DTSTAMP:20260503T235217
CREATED:20240214T105028Z
LAST-MODIFIED:20240301T081713Z
UID:10002681-1665140400-1665144000@cmsa.fas.harvard.edu
SUMMARY:Principal flow\, sub-manifold and boundary
DESCRIPTION:Member Seminar  \nSpeaker: Zhigang Yao \nTitle: Principal flow\, sub-manifold and boundary \nAbstract: While classical statistics has dealt with observations which are real numbers or elements of a real vector space\, nowadays many statistical problems of high interest in the sciences deal with the analysis of data which consist of more complex objects\, taking values in spaces which are naturally not (Euclidean) vector spaces but which still feature some geometric structure. I will discuss the problem of finding principal components to the multivariate datasets\, that lie on an embedded nonlinear Riemannian manifold within the higher-dimensional space. The aim is to extend the geometric interpretation of PCA\, while being able to capture the non-geodesic form of variation in the data. I will introduce the concept of a principal sub-manifold\, a manifold passing through the center of the data\, and at any point on the manifold extending in the direction of highest variation in the space spanned by the eigenvectors of the local tangent space PCA. We show the principal sub-manifold yields the usual principal components in Euclidean space. We illustrate how to find\, use and interpret the principal sub-manifold\, by which a principal boundary can be further defined for data sets on manifolds.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-10722/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221011T110000
DTEND;TZID=America/New_York:20221011T120000
DTSTAMP:20260503T235217
CREATED:20230730T183036Z
LAST-MODIFIED:20240215T091450Z
UID:10001152-1665486000-1665489600@cmsa.fas.harvard.edu
SUMMARY:The Penrose Inequality as a Constraint on Low Energy Quantum Gravity
DESCRIPTION:Swampland Seminar\n\nSpeaker: Aasmund Folkestad (MIT)\n\n\nTitle: The Penrose Inequality as a Constraint on Low Energy Quantum Gravity\n\nAbstract: In this talk\, I argue that the Penrose inequality (PI) can be used to constrain low energy theories compatible AdS/CFT\, and possibly also quantum gravity in flat space. Focusing on AdS/CFT\, it is shown that the PI can be violated for minimally coupled scalar fields\, and I produce exclusion plots on couplings that respect the PI. I also present numerical evidence that top-down scalar theories and supersymmetric theories respect the PI. Finally\, similar to the Breitenlohner-Freedman bound\, I give a necessary condition for the stability AdS that constrains coupling constants (beyond the scalar mass).
URL:https://cmsa.fas.harvard.edu/event/swampland_101122/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Swampland Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221012T090000
DTEND;TZID=America/New_York:20221012T100000
DTSTAMP:20260503T235217
CREATED:20230705T072724Z
LAST-MODIFIED:20240229T103813Z
UID:10001140-1665565200-1665568800@cmsa.fas.harvard.edu
SUMMARY:Engineering topological phases with a superlattice potential
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Jennifer Cano (Stony Brook and Flatiron Institute) \nTitle: Engineering topological phases with a superlattice potential\n\nAbstract: We propose an externally imposed superlattice potential as a platform for manipulating topological phases\, which has both advantages and disadvantages compared to a moire superlattice. In the first example\, we apply the superlattice potential to the 2D surface of a 3D topological insulator. The superlattice potential creates tunable van Hove singularities\, which\, when combined with strong spin-orbit coupling and Coulomb repulsion give rise to a topological meron lattice spin texture. Thus\, the superlattice potential provides a new route to the long sought-after goal of realizing spontaneous magnetic order on the surface of a 3D TI. In the second example\, we show that a superlattice potential applied to Bernal-stacked bilayer graphene can generate flat Chern bands\, similar to in twisted bilayer graphene\, whose bandwidth can be as small as a few meV. The superlattice potential offers flexibility in both lattice size and geometry\, making it a promising alternative to achieve designer flat bands without a moire heterostructure.
URL:https://cmsa.fas.harvard.edu/event/tqms_101222/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-10.12.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221012T123000
DTEND;TZID=America/New_York:20221012T133000
DTSTAMP:20260503T235217
CREATED:20230817T173346Z
LAST-MODIFIED:20240222T165414Z
UID:10001267-1665577800-1665581400@cmsa.fas.harvard.edu
SUMMARY:Complete disorder is impossible: Some topics in Ramsey theory
DESCRIPTION:Colloquium \nSpeaker: James Cummings\,Carnegie Mellon University \nTitle: Complete disorder is impossible: Some topics in Ramsey theory \nAbstract: The classical infinite Ramsey theorem states that if we colour pairs of natural numbers using two colours\, there is an infinite set all of whose pairs get the same colour. This is the beginning of a rich theory\, which touches on many areas of mathematics including graph theory\, set theory and dynamics. I will give an overview of Ramsey theory\, emphasizing the diverse ideas which are at play in this area.
URL:https://cmsa.fas.harvard.edu/event/collquium-101222/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.12.22-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221013T103000
DTEND;TZID=America/New_York:20221013T233000
DTSTAMP:20260503T235217
CREATED:20240215T091921Z
LAST-MODIFIED:20240229T092506Z
UID:10002712-1665657000-1665703800@cmsa.fas.harvard.edu
SUMMARY:Strong Cosmic Censorship
DESCRIPTION:General Relativity Seminar \n\nSpeaker: Professor Oscar Dias (University of Southampton) \n\nTitle: Strong Cosmic Censorship \nAbstract: Generically\, strong cosmic censorship (SCC) is the statement that physics within general relativity should be predicted from initial data prescribed on a Cauchy hypersurface. In this talk I will review how fine-tuned versions of SCC have been formulated and evolved along the last decades up to the point where we believe that Christodoulou’s version is true in asymptotically flat spacetimes. However\, I will also describe that in recent years it was found that this is no longer necessarily true for some other backgrounds\, namely in some de Sitter (with a positive cosmological constant) spacetimes or even in rotating BTZ black holes in 3-dimensional Anti-de Sitter spacetime. Finally\, I will discuss some possibilities (quantum effects\, non-smooth initial data\,…) that might restore SCC in those backgrounds where the standard formulation of the conjecture is violated.
URL:https://cmsa.fas.harvard.edu/event/gr_101322/
LOCATION:Virtual
CATEGORIES:General Relativity Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221014T093000
DTEND;TZID=America/New_York:20221014T103000
DTSTAMP:20260503T235217
CREATED:20230825T081331Z
LAST-MODIFIED:20240215T093308Z
UID:10001299-1665739800-1665743400@cmsa.fas.harvard.edu
SUMMARY:Singularities of the quantum connection on a Fano variety
DESCRIPTION:Algebraic Geometry in String Theory Seminar \n\n\n\n\n\nSpeaker: Daniel Pomerleano\, UMass Boston \nTitle: Singularities of the quantum connection on a Fano variety \nAbstract: The small quantum connection on a Fano variety is one of the simplest objects in enumerative geometry. Nevertheless\, it is the subject of far-reaching conjectures known as the Dubrovin/Gamma conjectures. Traditionally\, these conjectures are made for manifolds with semi-simple quantum cohomology or more generally for Fano manifolds whose quantum connection is of unramified exponential type at q=\infty. \nI will explain a program\, joint with Paul Seidel\, to show that this unramified exponential type property holds for all Fano manifolds M carrying a smooth anticanonical divisor D. The basic idea of our argument is to view these structures through the lens of a noncommutative Landau-Ginzburg model intrinsically attached to (M\, D).
URL:https://cmsa.fas.harvard.edu/event/agst-102122/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebraic-Geometry-in-String-Theory-10.14.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221014T110000
DTEND;TZID=America/New_York:20221014T120000
DTSTAMP:20260503T235217
CREATED:20240214T103536Z
LAST-MODIFIED:20240301T081027Z
UID:10002676-1665745200-1665748800@cmsa.fas.harvard.edu
SUMMARY:Quantum magnet chains and Kashiwara crystals
DESCRIPTION:Speaker: Leonid Rybnikov\, Harvard CMSA/National Research University Higher School of Economics \nTitle: Quantum magnet chains and Kashiwara crystals \nAbstract: Solutions of the algebraic Bethe ansatz for quantum magnet chains are\, generally\, multivalued functions of the parameters of the integrable system. I will explain how to compute some monodromies of solutions of Bethe ansatz for the Gaudin magnet chain. Namely\, the Bethe eigenvectors in the Gaudin model can be regarded as a covering of the Deligne-Mumford moduli space of stable rational curves\, which is unramified over the real locus of the Deligne-Mumford space. The monodromy action of the fundamental group of this space (called cactus group) on the eigenlines can be described very explicitly in purely combinatorial terms of Kashiwara crystals — i.e. combinatorial objects modeling the tensor category of finite-dimensional representations of a semisimple Lie algebra g. More specifically\, this monodromy action is naturally equivalent to the action of the same group by commutors (i.e. combinatorial analog of a braiding) on a tensor product of Kashiwara crystals. This is joint work with Iva Halacheva\, Joel Kamnitzer\, and Alex Weekes.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-101422/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-10.14.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221017T090000
DTEND;TZID=America/New_York:20221017T103000
DTSTAMP:20260503T235217
CREATED:20240215T104548Z
LAST-MODIFIED:20240229T101247Z
UID:10002745-1665997200-1666002600@cmsa.fas.harvard.edu
SUMMARY:Topological Wick Rotation and Holographic duality
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Liang Kong (Sustech) \nTitle: Topological Wick Rotation and Holographic duality \nAbstract: I will explain a new type of holographic dualities between\nn+1D topological orders with a chosen boundary condition and nD\n(potentially gapless) quantum liquids. It is based on the idea of\ntopological Wick rotation\, a notion which was first used in\narXiv:1705.01087 and was named\, emphasized and generalized later in\narXiv:1905.04924. Examples of these holographic dualities include the\nduality between 2+1D toric code model and 1+1D Ising chain and its\nfinite-group generalizations (independently discovered by many\nothers); those between 2+1D topological orders and 1+1D rational\nconformal field theories; and those between n+1D finite gauge theories\nwith a gapped boundary and nD gapped quantum liquids. I will also\nbriefly discuss some generalizations of this holographic duality and\nits relation to AdS/CFT duality.
URL:https://cmsa.fas.harvard.edu/event/qm_101722/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-Seminar-10.17.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221018T090000
DTEND;TZID=America/New_York:20221018T103000
DTSTAMP:20260503T235217
CREATED:20240215T104318Z
LAST-MODIFIED:20240229T093815Z
UID:10002744-1666083600-1666089000@cmsa.fas.harvard.edu
SUMMARY:On the six-dimensional origin of non-invertible symmetries
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Michele Del Zotto (Uppsala University) \nTitle: On the six-dimensional origin of non-invertible symmetries \nAbstract: I will present a review about recent progress in charting non-invertible symmetries for four-dimensional quantum field theories that have a six-dimensional origin. These include in particular N=4 supersymmetric Yang-Mills theories\, and also a large class of N=2 supersymmetric theories which are conformal and do not have a conventional Lagrangian description (the so-called theories of “class S”). Among the main results\, I will explain criteria for identifying examples of systems with intrinsic and non-intrinsic non-invertible symmetries\, as well as explore their higher dimensional origin. This seminar is based on joint works with Vladimir Bashmakov\, Azeem Hasan\, and Justin Kaidi. \n 
URL:https://cmsa.fas.harvard.edu/event/qm_101822/
LOCATION:Virtual
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-Seminar-10.18.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221019T123000
DTEND;TZID=America/New_York:20221019T133000
DTSTAMP:20260503T235217
CREATED:20230817T173735Z
LAST-MODIFIED:20240214T113414Z
UID:10001268-1666182600-1666186200@cmsa.fas.harvard.edu
SUMMARY:The Mobility Edge of Lévy Matrices
DESCRIPTION:Colloquium \nSpeaker: Patrick Lopatto (Brown) \nTitle: The Mobility Edge of Lévy Matrices \nAbstract: Lévy matrices are symmetric random matrices whose entry distributions lie in the domain of attraction of an alpha-stable law; such distributions have infinite variance when alpha is less than 2. Due to the ubiquity of heavy-tailed randomness\, these models have been broadly applied in physics\, finance\, and statistics. When the entries have infinite mean\, Lévy matrices are predicted to exhibit a phase transition separating a region of delocalized eigenvectors from one with localized eigenvectors. We will discuss the physical context for this conjecture\, and describe a result establishing it for values of alpha close to zero and one. This is joint work with Amol Aggarwal and Charles Bordenave.
URL:https://cmsa.fas.harvard.edu/event/collquium-101922/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.19.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221019T140000
DTEND;TZID=America/New_York:20221019T150000
DTSTAMP:20260503T235217
CREATED:20230808T184955Z
LAST-MODIFIED:20240215T095357Z
UID:10001213-1666188000-1666191600@cmsa.fas.harvard.edu
SUMMARY:Towards Faithful Reasoning Using Language Models
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Antonia Creswell\, DeepMind \nTitle: Towards Faithful Reasoning Using Language Models \nAbstract: Language models are showing impressive performance on many natural language tasks\, including question-answering. However\, language models – like most deep learning models – are black boxes. We cannot be sure how they obtain their answers. Do they reason over relevant knowledge to construct an answer or do they rely on prior knowledge – baked into their weights – which may be biased? An alternative approach is to develop models whose output is a human interpretable\, faithful reasoning trace leading to an answer. In this talk we will characterise faithful reasoning in terms of logically valid reasoning and demonstrate where current reasoning models fall short. Following this\, we will introduce Selection-Inference\, a faithful reasoning model\, whose causal structure mirrors the requirements for valid reasoning. We will show that our model not only produces more accurate reasoning traces but also improves final answer accuracy. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/nt-101922/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/10.19.2022.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20221019T160000
DTEND;TZID=America/New_York:20221019T173000
DTSTAMP:20260503T235217
CREATED:20230705T073706Z
LAST-MODIFIED:20240229T103702Z
UID:10001139-1666195200-1666200600@cmsa.fas.harvard.edu
SUMMARY:Symmetric Mass Generation
DESCRIPTION:Topological Quantum Matter Seminar \nSpeaker: Yizhuang You\, UC San Diego \nTitle: Symmetric Mass Generation\n\nAbstract: Symmetric mass generation (SMG) is a novel mechanism for massless fermions to acquire a mass via a strong-coupling non-perturbative interaction effect. In contrast to the conventional Higgs mechanism for fermion mass generation\, the SMG mechanism does not condense any fermion bilinear coupling and preserves the full symmetry. It is connected to a broad range of topics\, including anomaly cancellation\, topological phase classification\, and chiral fermion regularization. In this talk\, I will introduce SMG through toy models\, and review the current understanding of the SMG transition. I will also mention recent numerical efforts to investigate the SMG phenomenon. I will conclude the talk with remarks on future directions.
URL:https://cmsa.fas.harvard.edu/event/tqms_101922/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Topological Quantum Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Topological-Seminar-10.19.22.png
END:VEVENT
END:VCALENDAR