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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220906T130000
DTEND;TZID=America/New_York:20220906T140000
DTSTAMP:20260410T121937
CREATED:20230824T174654Z
LAST-MODIFIED:20240301T091523Z
UID:10001311-1662469200-1662472800@cmsa.fas.harvard.edu
SUMMARY:State Diagram of Cancer Cell Unjamming Predicts Metastatic Risk
DESCRIPTION:Speaker: Josef Käs\, Leipzig University \nTitle: State Diagram of Cancer Cell Unjamming Predicts Metastatic Risk \nAbstract: Distant metastasis is probably the most lethal hallmark of cancer. Due to a lack of suitable markers\, cancer cell motility only has a negligible impact on current diagnosis. Based on cell unjamming we derive a cell motility marker for static histological images. This enables us to sample huge numbers of breast cancer patient data to derive a comprehensive state diagram of unjamming as a collective transition in cell clusters of solid tumors. As recently discovered\, cell unjamming transitions occur in embryonic development and as pathological changes in diseases such as cancer. No consensus has been achieved on the variables and the parameter space that describe this transition. Cell shapes or densities based on different unjamming models have been separately used to describe the unjamming transition under different experimental conditions. Moreover\, the role of the nucleus is not considered in the current unjamming models. Mechanical stress propagating through the tissue mechanically couples the cell nuclei mediated by the cell’s cytoplasm\, which strongly impacts jamming. \nBased on our exploratory retrospective clinical study with N=1\,380 breast cancer patients and vital cell tracking in patient-derived tumor explants\, we find that the unjamming state diagram depends on cell and nucleus shapes as one variable and the nucleus number density as the other that measures the cytoplasmic spacing between the nuclei. Our approach unifies previously controversial results into one state diagram. It spans a broad range of states that cancer cell clusters can assume in a solid tumor. We can use an empirical decision boundary to show that the unjammed regions in the diagram correlate with the patient’s risk for metastasis. \nWe conclude that unjamming within primary tumors is part of the metastatic cascade\, which significantly advances the understanding of the early metastatic events. With the histological slides of two independent breast cancer patients’ collectives\, we train (N=688) and validate (N=692) our quantitative prognostic index based on unjamming regarding metastatic risk. Our index corrects for false high- and low-risk predictions based on the invasion of nearby lymph nodes\, the current gold standard. Combining information derived from the nodal status with unjamming may reduce over- and under-treatment. \nVideo (Youtube)
URL:https://cmsa.fas.harvard.edu/event/state-diagram-of-cancer-cell-unjamming-predicts-metastatic-risk/
CATEGORIES:Active Matter Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Active-Matter-Seminar-09.06.22.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220907T090000
DTEND;TZID=America/New_York:20220907T103000
DTSTAMP:20260410T121938
CREATED:20240216T115218Z
LAST-MODIFIED:20240229T105716Z
UID:10002769-1662541200-1662546600@cmsa.fas.harvard.edu
SUMMARY:Gifts from anomalies: new results on quantum critical transport in non- Fermi liquids
DESCRIPTION:Quantum Matter in Mathematics and Physics Seminar \nSpeaker: Zhengyan Darius Shi (MIT)\n\n\nTitle: Gifts from anomalies: new results on quantum critical transport in non-Fermi liquids\nAbstract: Non-Fermi liquid phenomena arise naturally near Landau ordering transitions in metallic systems. Here\, we leverage quantum anomalies as a powerful nonperturbative tool to calculate optical transport in these models in the infrared limit. While the simplest such models with a single boson flavor (N=1) have zero incoherent conductivity\, a recently proposed large N deformation involving flavor-random Yukawa couplings between N flavors of bosons and fermions admits a nontrivial incoherent conductivity  (z is the boson dynamical exponent) when the order parameter is odd under inversion. The presence of incoherent conductivity in the random flavor model is a consequence of its unusual anomaly structure. From this we conclude that the large N deformation does not share important nonperturbative features with the physical N = 1 model\, though it remains an interesting theory in its own right. Going beyond the IR fixed point\, we also consider the effects of irrelevant operators and show\, within the scope of the RPA expansion\, that the old result   due to Kim et al. is incorrect for inversion-odd order parameters.
URL:https://cmsa.fas.harvard.edu/event/gifts-from-anomalies-new-results-on-quantum-critical-transport-in-non-fermi-liquids/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-Seminar-09.07.22-1-2.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220908T103000
DTEND;TZID=America/New_York:20220908T113000
DTSTAMP:20260410T121938
CREATED:20240214T105852Z
LAST-MODIFIED:20240301T084331Z
UID:10002689-1662633000-1662636600@cmsa.fas.harvard.edu
SUMMARY:The second law of black hole mechanics in effective field theory
DESCRIPTION:General Relativity Seminar \nSpeaker: Professor Harvey Reall (University of Cambridge)  \nTitle: The second law of black hole mechanics in effective field theory \nAbstract: I shall discuss the second law of black hole mechanics in gravitational theories with higher derivative terms in the action. Wall has described a method for defining an entropy that satisfies the second law to linear order in perturbations around a stationary black hole. I shall explain how this can be extended to define an entropy that satisfies the second law to quadratic order in perturbations\, provided that one treats the higher derivative terms in the sense of effective field theory. This talk is based on work with Stefan Hollands and Aron Kovacs. \nVideo
URL:https://cmsa.fas.harvard.edu/event/the-second-law-of-black-hole-mechanics-in-effective-field-theory/
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:20220909T120000
DTEND;TZID=America/New_York:20220909T130000
DTSTAMP:20260410T121938
CREATED:20240301T084734Z
LAST-MODIFIED:20240301T084734Z
UID:10002889-1662724800-1662728400@cmsa.fas.harvard.edu
SUMMARY:Duality in Einstein’s Gravity
DESCRIPTION:Title: 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/duality-in-einsteins-gravity/
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:20220913T093000
DTEND;TZID=America/New_York:20220913T110000
DTSTAMP:20260410T121938
CREATED:20240216T114850Z
LAST-MODIFIED:20240229T105748Z
UID:10002768-1663061400-1663066800@cmsa.fas.harvard.edu
SUMMARY:Non-invertible Symmetries in Nature
DESCRIPTION:Quantum Matter in Mathematics and Physics \n\nSpeaker: Yichul Cho (SUNY Stony Brook)\nTitle: Non-invertible Symmetries in Nature \nAbstract: In this talk\, I will discuss non-invertible symmetries in\nfamiliar 3+1d quantum field theories describing our Nature. In\nmassless QED\, the classical U(1) axial symmetry is not completely\nbroken by the ABJ anomaly. Instead\, it turns into a discrete\,\nnon-invertible symmetry. The non-invertible symmetry operator is\nobtained by dressing the naïve U(1) axial symmetry operator with a\nfractional quantum Hall state. We also find a similar non-invertible\nsymmetry in the massless limit of QCD\, which provides an alternative\nexplanation for the neutral pion decay. In the latter part of the\ntalk\, I will discuss non-invertible time-reversal symmetries in 3+1d\ngauge theories. In particular\, I will show that in free Maxwell\ntheory\, there exists a non-invertible time-reversal symmetry at every\nrational value of the theta angle. \nBased on https://arxiv.org/abs/2205.05086 and https://arxiv.org/abs/2208.04331. \n 
URL:https://cmsa.fas.harvard.edu/event/non-invertible-symmetries-in-nature/
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-Seminar-09.13.22-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220914T120000
DTEND;TZID=America/New_York:20220914T130000
DTSTAMP:20260410T121938
CREATED:20240214T114614Z
LAST-MODIFIED:20240229T110925Z
UID:10002707-1663156800-1663160400@cmsa.fas.harvard.edu
SUMMARY:Strategyproof-Exposing Mechanisms Descriptions
DESCRIPTION:Colloquium \nSpeaker: Yannai Gonczarowski (Harvard)\n\nTitle: Strategyproof-Exposing Mechanisms Descriptions \nAbstract: One of the crowning achievements of the field of Mechanism Design has been the design and usage of the so-called “Deferred Acceptance” matching algorithm. Designed in 1962 and awarded the Nobel Prize in 2012\, this algorithm has been used around the world in settings ranging from matching students to schools to matching medical doctors to residencies. A hallmark of this algorithm is that unlike many other matching algorithms\, it is “strategy-proof”: participants can never gain by misreporting their preferences (say\, over schools) to the algorithm. Alas\, this property is far from apparent from the algorithm description. Its mathematical proof is so delicate and complex\, that (for example) school districts in which it is implemented do not even attempt to explain to students and parents why this property holds\, but rather resort to an appeal to authority: Nobel laureates have proven this property\, so one should listen to them. Unsurprisingly perhaps\, there is a growing body of evidence that participants in Deferred Acceptance attempt (unsuccessfully) to “game it\,” which results in a suboptimal match for themselves and for others. \nBy developing a novel framework of algorithm description simplicity—grounded at the intersection between Economics and Computer Science—we present a novel\, starkly different\, yet equivalent\, description for the Deferred Acceptance algorithm\, which\, in a precise sense\, makes its strategyproofness far more apparent. Our description does have a downside\, though: some other of its most fundamental properties—for instance\, that no school exceeds its capacity—are far less apparent than from all traditional descriptions of the algorithm. Using the theoretical framework that we develop\, we mathematically address the question of whether and to what extent this downside is unavoidable\, providing a possible explanation for why our description of the algorithm has eluded discovery for over half a century. Indeed\, it seems that in the design of all traditional descriptions of the algorithm\, it was taken for granted that properties such as no capacity getting exceeded should be apparent. Our description emphasizes the property that is important for participants to correctly interact with the algorithm\, at the expense of properties that are mostly of interest to policy makers\, and thus has the potential of vastly improving access to opportunity for many populations. Our theory provides a principled way of recasting algorithm descriptions in a way that makes certain properties of interest easier to explain and grasp\, which we also support with behavioral experiments in the lab. \nJoint work with Ori Heffetz and Clayton Thomas.
URL:https://cmsa.fas.harvard.edu/event/collquium-title-tba/
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-09.14.22-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220914T140000
DTEND;TZID=America/New_York:20220914T150000
DTSTAMP:20260410T121938
CREATED:20230808T183823Z
LAST-MODIFIED:20240301T091205Z
UID:10001210-1663164000-1663167600@cmsa.fas.harvard.edu
SUMMARY:Breaking the one-mind-barrier in mathematics using formal verification
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Johan Commelin\, Mathematisches Institut\, Albert-Ludwigs-Universität Freiburg \nTitle: Breaking the one-mind-barrier in mathematics using formal verification \nAbstract: In this talk I will argue that formal verification helps break the one-mind-barrier in mathematics. Indeed\, formal verification allows a team of mathematicians to collaborate on a project\, without one person understanding all parts of the project. At the same time\, it also allows a mathematician to rapidly free mental RAM in order to work on a different component of a project. It thus also expands the one-mind-barrier. \nI will use the Liquid Tensor Experiment as an example\, to illustrate the above two points. This project recently finished the formalization of the main theorem of liquid vector spaces\, following up on a challenge by Peter Scholze. \nVideo
URL:https://cmsa.fas.harvard.edu/event/breaking-the-one-mind-barrier-in-mathematics-using-formal-verification/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:New Technologies in Mathematics Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220915T103000
DTEND;TZID=America/New_York:20220915T113000
DTSTAMP:20260410T121938
CREATED:20240214T111637Z
LAST-MODIFIED:20240229T104038Z
UID:10002693-1663237800-1663241400@cmsa.fas.harvard.edu
SUMMARY:The Gregory-Laflamme instability of black strings revisited
DESCRIPTION:General Relativity Seminar\n\nTitle: The Gregory-Laflamme instability of black strings revisited\n \nAbstract: In this talk I will discuss our recent work that reproduces and extends the famous work of Lehner and Pretorius on the end point of the Gregory-Laflamme instability of black strings. We consider black strings of different thicknesses and our numerics allow us to get closer to the singularity than ever before. In particular\, while our results support the picture of the formation of a naked singularity in finite asymptotic time\, the process is more complex than previously thought. In addition\, we obtain some hints about the nature of the singularity that controls the pinch off of the string.
URL:https://cmsa.fas.harvard.edu/event/title-tba-3/
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-09.15.22-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20220916T110000
DTEND;TZID=America/New_York:20220916T120000
DTSTAMP:20260410T121938
CREATED:20240214T105636Z
LAST-MODIFIED:20240301T084243Z
UID:10002686-1663326000-1663329600@cmsa.fas.harvard.edu
SUMMARY:Derivation of AdS/CFT for Vector Models
DESCRIPTION:Member Seminar\n\nSpeaker: Shai Chester\n\nTitle: Derivation of AdS/CFT for Vector Models\nAbstract: We derive an explicit map at finite N between the singlet sector of the free and critical O(N) and U(N) vector models in any spacetime dimension above two\, and a bulk higher spin theory in anti-de Sitter space in one higher dimension. For the boundary theory\, we use the bilocal formalism of Jevicki et al to restrict to the singlet sector of the vector model. The bulk theory is defined from the boundary theory via our mapping\, and is a consistent quantum higher spin theory with a well defined action. Our mapping relates bilocal operators in the boundary theory to higher spin fields in the bulk\, while single trace local operators in the boundary theory are related to boundary values of higher spin fields. We also discuss generalizations of the map to gauge theories\, and at finite temperature.
URL:https://cmsa.fas.harvard.edu/event/derivation-of-ads-cft-for-vector-models/
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:20220919T110000
DTEND;TZID=America/New_York:20220919T120000
DTSTAMP:20260410T121938
CREATED:20230730T182302Z
LAST-MODIFIED:20240229T103619Z
UID:10001151-1663585200-1663588800@cmsa.fas.harvard.edu
SUMMARY:The story of the information paradox
DESCRIPTION:Swampland Seminar\n\nSpeaker: Samir Mathur (Ohio State)\n\nTitle: The story of the information paradox\n\nAbstract:  In 1975 Hawking argued that black hole evaporation would lead to a loss of unitarity in quantum theory.  The small corrections theorem made Hawking’s argument into a precise statement: if semiclassical physics hold to leading order in any gently curved region of spacetime\, then there can be no resolution to the paradox. In string theory\, whenever people have been able to construct microstates explicutly\, the states turned out to be horizon sized objects (fuzzballs) with no horizon; such a structure of microstates resolves the information paradox since their is no pair creation at a vacuum horizon. There have been a set of parallel attempts to resolve the paradox (with ideas involving wormholes\, islands etc) where the horizon is smooth in some leading approximation. An analysis of such models however indicated that in each case the exact quantum gravity theory would either have to be nonunitary or to have dynamics at infinity that is conflict with usual low energy physics in the lab.
URL:https://cmsa.fas.harvard.edu/event/title-tba-4/
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:20220921T090000
DTEND;TZID=America/New_York:20220921T100000
DTSTAMP:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121938
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:20260410T121939
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:20260410T121939
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:20260410T121939
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
END:VCALENDAR