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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250127T093000
DTEND;TZID=America/New_York:20250127T103000
DTSTAMP:20260504T015119
CREATED:20250123T201747Z
LAST-MODIFIED:20250127T204324Z
UID:10003668-1737970200-1737973800@cmsa.fas.harvard.edu
SUMMARY:Joint BHI/CMSA Foundation Seminar: Quantum Criticality in Black Hole Dynamics
DESCRIPTION:Joint BHI/CMSA Foundation Seminar \nLocation: BHI Seminar Room \nSpeaker: Uri Kol\, Harvard CMSA \n\nTitle: Quantum Criticality in Black Hole Dynamics \nAbstract: Black hole perturbation theory captures a few important effects in the dynamics of binary mergers\, such as tidal deformations and the decay of ringdown modes\, as well as the physics of the photon ring. However\, deriving qualitative results that lead to robust predictions in this theory remains a challenging problem\, despite a rich scientific history.\nMotivated by the immense experimental progress made in the field over the past decade\, in this talk I will describe a new critical phenomenon emerging in the theory of perturbations around Kerr black holes. A critical point is identified at zero black hole temperature\, giving rise to a wide regime at finite temperatures which is dominated by critical perturbations. As in quantum many-body systems\, the physics in the critical regime is described exclusively by a set of critical exponents\, therefore leading to robust predictions that are unique to the Kerr metric.
URL:https://cmsa.fas.harvard.edu/event/foundation_12725/
LOCATION:Black Hole Initiative\, 20 Garden Street\, Cambridge MA\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Foundation Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-BHI-Joint-Foundations-Seminar-1.27.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250127T150000
DTEND;TZID=America/New_York:20250127T160000
DTSTAMP:20260504T015119
CREATED:20240907T194212Z
LAST-MODIFIED:20250124T171827Z
UID:10003471-1737990000-1737993600@cmsa.fas.harvard.edu
SUMMARY:A homotopy of 2d SCFTs and an implication for Topological Modular Forms
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Vivek Saxena (YITP Stony Brook and NHETC Rutgers) \nTitle: A homotopy of 2d SCFTs and an implication for Topological Modular Forms \nAbstract: The Segal-Stolz-Teichner conjecture states that there exists an isomorphism between deformation classes of two-dimensional N=(0\,1) superconformal field theories (SCFTs) and generalized cohomology classes known as Topological Modular Forms (TMFs). Such 2d N=(0\,1) SCFTs arise naturally in physics as worldsheet theories of (possibly compactified) heterotic strings. Recently\, this connection was used to prove the absence of global anomalies in heterotic string theories and make predictions about topological terms in their low-energy effective actions\, among other things. \nIn this talk\, after giving a brief overview of these ideas\, I will describe a physics ”proof” (using methods from 2d CFT) of a mathematical conjecture of Tachikawa and Yamashita about TMF classes in degree 31. Specifically\, by examining the two worldsheet theories corresponding to two T-dual nine-dimensional spacetime non-supersymmetric heterotic string theories (namely the $(E_8)_1 \times (E_8)_1$ theory and the $(E_8)_2$ theory)\, I will argue that the $(E_8)_2$ theory corresponds to the unique nontrivial torsion element $[(E_8)_2]$ of TMF$^{31}$ with zero mod-2 elliptic genus.
URL:https://cmsa.fas.harvard.edu/event/qft_12725/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QFT-and-Physical-Mathematics-1.27.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250128T161500
DTEND;TZID=America/New_York:20250128T181500
DTSTAMP:20260504T015119
CREATED:20250124T150923Z
LAST-MODIFIED:20250124T151709Z
UID:10003653-1738080900-1738088100@cmsa.fas.harvard.edu
SUMMARY:Review of the excision property in factorization homology
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Keyou Zeng\, Harvard CMSA \nTitle: Review of the excision property in factorization homology
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_12825/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-1.28.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250130T100000
DTEND;TZID=America/New_York:20250130T110000
DTSTAMP:20260504T015119
CREATED:20250127T161217Z
LAST-MODIFIED:20250127T164602Z
UID:10003675-1738231200-1738234800@cmsa.fas.harvard.edu
SUMMARY:Stochastic Process and Noncommutative Geometry
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Zichang Wang (Tsinghua University) \nTitle: Stochastic Process and Noncommutative Geometry \nAbstract: We explain a stochastic approach to topological field theory and present a case study of quantum mechanical model and its relation to noncommutative geometry. For detail reference\, see https://arxiv.org/abs/2501.12360 \n  \n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_13025/
LOCATION:Hybrid
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-1.30.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250130T160000
DTEND;TZID=America/New_York:20250130T173000
DTSTAMP:20260504T015119
CREATED:20240710T194728Z
LAST-MODIFIED:20241218T212836Z
UID:10003399-1738252800-1738258200@cmsa.fas.harvard.edu
SUMMARY:CMSA/MATH Welcome Back Gathering
DESCRIPTION:Thursday\, Jan. 30\, 2025 \n4:00 pm \nAll CMSA and Math affiliates are invited. \n 
URL:https://cmsa.fas.harvard.edu/event/cmsa-math_13025/
LOCATION:CMSA 20 Garden Street Cambridge\, Massachusetts 02138 United States
CATEGORIES:Event
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250131T120000
DTEND;TZID=America/New_York:20250131T130000
DTSTAMP:20260504T015119
CREATED:20250127T180141Z
LAST-MODIFIED:20250127T180704Z
UID:10003638-1738324800-1738328400@cmsa.fas.harvard.edu
SUMMARY:Smooth projective fibrations over the projective line and their sections
DESCRIPTION:Member Seminar \nSpeaker: Iacopo Brivio \nTitle: Smooth projective fibrations over the projective line and their sections \nAbstract: Suppose $f\colon X\to \mathbf{CP}^1$ is a smooth projective fibration\, is it then true that $f$ has a section? This deceptively simple result was established by Seidel and McDuff using deep methods of symplectic geometry. Alex Pieloch recently generalized this to morphisms with at most one singular fibers and furthermore showed that $X$ uniruled\, that is covered by images of $\mathbf{P}^1$. In my talk I will explain how to recover Pieloch’s result from the Good Minimal Model Conjecture. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-13125/
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-1.31.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250203T150000
DTEND;TZID=America/New_York:20250203T160000
DTSTAMP:20260504T015119
CREATED:20250124T171714Z
LAST-MODIFIED:20250131T150210Z
UID:10003672-1738594800-1738598400@cmsa.fas.harvard.edu
SUMMARY:Topological to Gravitational Leptogenesis\, via Ultra Unification 
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Juven Wang (LIMS\, Royal Institution) \nTitle: Topological to Gravitational Leptogenesis\, via Ultra Unification \nAbstract: We propose a new mechanism for leptogenesis\, named Topological Leptogenesis\, in which dark matter consists of topological order\, so gapped anyon excitations decay to generate the Standard Model lepton asymmetry. Topological Leptogenesis is in contrast with the Majorana Leptogenesis and Gravitational Leptogenesis. In the standard Majorana Leptogenesis\, the baryon asymmetry of the present universe is attributed to the leptogenesis from the sterile right-handed neutrino with heavy Majorana fermion mass decaying into the Standard Model leptons in the very early universe\, while the electroweak sphaleron causes baryogenesis at a later time. Gravitational leptogenesis can be regarded as an intermediate step between Majorana particle leptogenesis and topological non-particle leptogenesis. Topological Leptogenesis is derived out of Ultra Unification constructed from a mod 16 nonperturbative global anomaly cancellation that adds a symmetry-extended anomalous gapped topological quantum field theory (TQFT) to the Standard Model. Thus (1) the Beyond-the-Standard-Model (BSM) Dark Matter partly consists of Topological Order with low energy TQFT\, while there are anyon string excitations above the energy gap. (2) The 5th force is a Topological Discrete Gauge Force of (B-L) that mediates between the Standard Model particles\, the BSM Topological Order\, and gapped anyon string non-particle excitations. \nBased on https://arxiv.org/abs/2501.00607\, https://arxiv.org/abs/2012.15860\, https://arxiv.org/abs/2302.14862 and https://arxiv.org/abs/2411.05786.
URL:https://cmsa.fas.harvard.edu/event/qft_2325/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QFT-and-Physical-Mathematics-2.3.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250203T163000
DTEND;TZID=America/New_York:20250203T173000
DTSTAMP:20260504T015119
CREATED:20240903T194951Z
LAST-MODIFIED:20250130T165403Z
UID:10003434-1738600200-1738603800@cmsa.fas.harvard.edu
SUMMARY:Rational approximation and the AAA algorithm
DESCRIPTION:Colloquium \nSpeaker: Nick Trefethen\, Harvard University \nTitle: Rational approximation and the AAA algorithm \nApproximation by rational functions used to be mainly a theoretical subject\, but with the introduction of the AAA algorithm in 2018\, it became computationally practical and indeed easy. The implications for what we can do numerically are enormous. This talk will outline the algorithm and demonstrate its application to a collection of problems. We can also use it to demonstrate the potential theory that underlies the theory of rational approximation\, a topic that goes back to Joseph Walsh here at Harvard a century ago.
URL:https://cmsa.fas.harvard.edu/event/colloquium-2325/
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-2.3.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250204T110000
DTEND;TZID=America/New_York:20250204T120000
DTSTAMP:20260504T015119
CREATED:20240903T192049Z
LAST-MODIFIED:20250130T190257Z
UID:10003428-1738666800-1738670400@cmsa.fas.harvard.edu
SUMMARY:The mass angular momentum inequality
DESCRIPTION:General Relativity Seminar \nSpeaker: Gilbert Weinstein\, Ariel University \nTitle: The mass angular momentum inequality \nAbstract: We show that either there is a counterexample to black hole uniqueness\, in the form of a regular axisymmetric stationary vacuum spacetime with an asymptotically flat end and multiple degenerate horizons which is ‘ADM stable’\, or the following statement holds. Complete\, simply connected\, maximal initial data sets for the Einstein equations with multiple ends that are either asymptotically flat or asymptotically cylindrical\, admit an ADM mass lower bound given by the square root of total angular momentum\, under the assumption of nonnegative energy density and axisymmetry. Moreover\, equality is achieved bound only for a constant time slice of an extreme Kerr spacetime. The proof is based on a novel flow of singular harmonic maps with hyperbolic plane target\, under which the renormalized harmonic energy is monotonically nonincreasing. Relevant properties of the flow are achieved through a refined asymptotic analysis of solutions to the linearized harmonic map equations.
URL:https://cmsa.fas.harvard.edu/event/general-relativity-seminar-2425/
LOCATION:Virtual
CATEGORIES:General Relativity Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-GR-Seminar-2.4.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250204T161500
DTEND;TZID=America/New_York:20250204T181500
DTSTAMP:20260504T015119
CREATED:20240917T160739Z
LAST-MODIFIED:20250124T152130Z
UID:10003513-1738685700-1738692900@cmsa.fas.harvard.edu
SUMMARY:Blob homology
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Sunghyuk Park\, Harvard CMSA \nTitle: Blob homology
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_2425/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-2.4.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250205T120000
DTEND;TZID=America/New_York:20250205T130000
DTSTAMP:20260504T015119
CREATED:20241104T201420Z
LAST-MODIFIED:20250106T151435Z
UID:10003591-1738756800-1738760400@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar: Subir Sachdev
DESCRIPTION:CMSA Q&A Seminar \n\nSpeaker: Subir Sachdev\, Harvard University \nTopic: What is a quantum critical region?
URL:https://cmsa.fas.harvard.edu/event/cmsaqa_2525/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Q-A-Seminar-2.5.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250206T100000
DTEND;TZID=America/New_York:20250206T110000
DTSTAMP:20260504T015119
CREATED:20241017T135403Z
LAST-MODIFIED:20250131T173042Z
UID:10003594-1738836000-1738839600@cmsa.fas.harvard.edu
SUMMARY:Quantum algebras and R-matrices from the equivariant affine Grassmannians
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Wenjun Niu\, Perimeter Institute \nTitle: Quantum algebras and R-matrices from the equivariant affine Grassmannians \nAbstract: In this talk\, I will explain my joint work with R. Abedin\, in which we construct\, for each Lie algebra g\, a Hopf algebra and a spectral R-matrix satisfying quantum Yang-Baxter equation. This Hopf algebra is a quantization of the Lie bi-algebra structure on T^*g[t] defined by Yang’s r-matrix\, and therefore we call it the Yangian of T^*g. The construction is based on the category of coherent sheaves on the equivariant affine Grassmannian associated to the formal group of g\, and is motivated by the study of the category of line defects in a 4 dimensional holomorphic-topological field theory. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_2625/
LOCATION:Virtual
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-2.6.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250207T140000
DTEND;TZID=America/New_York:20250207T154500
DTSTAMP:20260504T015119
CREATED:20250127T151529Z
LAST-MODIFIED:20250127T155730Z
UID:10003673-1738936800-1738943100@cmsa.fas.harvard.edu
SUMMARY:Is every knot isotopic to the unknot?
DESCRIPTION:Freedman CMSA Seminar \n*via Zoom* \nSpeaker: Sergey Melikhov\, Steklov Math Institute \nTitle: Is every knot isotopic to the unknot? \nAbstract: The following problem was stated by D. Rolfsen in his 1974 paper; according to R. Daverman it was being discussed since the mid-60s. Is every knot in $S^3$ isotopic (=homotopic through embeddings) to a PL knot — or\, equivalently\, to the unknot? In particular\, is the Bing sling isotopic to a PL knot? We show that the Bing sling $B$ is not isotopic to any PL knot by an isotopy which extends to an isotopy of any 2-component link obtained from $B$ by adding a disjoint component $Q$ such that $lk(B\,Q)=1$. Moreover\, the assertion remains true if the additional component is allowed to self-intersect\, and even to get replaced by a new one at any time instant $t$\, as long as it remains disjoint from the original component $K_t$ and represents the same conjugacy class as the old one in $G/[G’\,G”]$\, where $G=\pi_1(S^3\setminus K_t)$. The are examples showing that the latter result cannot be improved in certain ways. I plan to present a sketch of the proof\, modulo some ingredients. The details can be found in arXiv:2406.09365 and the main ingredients in arXiv:2406.09331 and arXiv:math/0312007v3. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/freedman_2725/
LOCATION:Virtual
CATEGORIES:Freedman Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Freedman-Seminar-2.7.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250210T093000
DTEND;TZID=America/New_York:20250210T103000
DTSTAMP:20260504T015119
CREATED:20250123T204528Z
LAST-MODIFIED:20250127T204354Z
UID:10003667-1739179800-1739183400@cmsa.fas.harvard.edu
SUMMARY:Joint BHI/CMSA Foundation Seminar: Quantum Effects Inside Black Holes
DESCRIPTION:Joint BHI/CMSA Foundation Seminar \nLocation: BHI seminar room \nSpeaker: Noa Zilberman (Princeton University) \nTitle: Quantum Effects Inside Black Holes \nAbstract: Astrophysical black holes are known to be rotating. Within classical General Relativity\, the simplest spacetime solution (the Kerr solution) describing a rotating black hole reveals a traversable passage through an inner horizon – which in turn may lead to another external universe. But does this remain the case when taking quantum effects into account? \nAnswering this question\, along others\, requires one to understand the manner in which quantum energy fluxes affect the internal geometry of a black hole. It has been widely anticipated\, yet inconclusive (till this work)\, that such effects would diverge at the inner horizon of a spinning black hole. This divergence\, if indeed takes place\, may drastically affect the internal black hole geometry\, potentially preventing the inner horizon traversability. Clarifying this issue requires the computation of the quantum energy fluxes in black hole interiors. However\, this has been a serious challenge for decades. \nUsing a combination of old and new methods\, we have managed to compute the quantum energy fluxes at the inner horizon of a spinning black hole\, in a vacuum state corresponding to an evaporating black hole. We found that these fluxes are either positive or negative\, depending on the black hole spin (and polar angle). The sign of these fluxes may be crucial to the nature of their backreaction on the geometry (as should be dictated by the semiclassical Einstein equation). \nIn this seminar\, we shall briefly describe the basic framework of semiclassical general relativity and the renormalization procedure\, and then present our novel results for the quantum fluxes at the inner horizon of a rotating black hole\, briefly mentioning possible implications for the inner horizon traversability. \n 
URL:https://cmsa.fas.harvard.edu/event/foundation_21025-2/
LOCATION:Black Hole Initiative\, 20 Garden Street\, Cambridge MA\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Foundation Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-BHI-Joint-Foundations-Seminar-2.10.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250210T110000
DTEND;TZID=America/New_York:20250210T120000
DTSTAMP:20260504T015119
CREATED:20250128T192122Z
LAST-MODIFIED:20250203T191001Z
UID:10003687-1739185200-1739188800@cmsa.fas.harvard.edu
SUMMARY:On 5d conformal matter
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Mario De Marco (UL Brussels) \nTitle: On 5d conformal matter \nAbstract: SCFTs with 8 supercharges lie at the sweet spot of the classification program of susy scale-invariant theories: with this amount of susy\, the classification is in principle achievable\, despite being non-trivial. In this talk\, I will present the geometric approach to the classification of 5d SCFTs\, based on geometric engineering on non-compact Calabi-Yau manifolds. The strategy is to imagine a 5d SCFT as a non-Lagrangian generalization of a quiver\, and to build this generalised quiver by gauging together indecomposable blocks\, called  “5d conformal matter theories”. In this talk\, I will start with a recap of the geometric construction of [2311.04984]. I will then present some forthcoming results\, concerning the (p\,q) web realization of 5d conformal matter theories\, their reduction to 4d\, their magnetic quiver\, and the discovery of exotic “trifundamental” and “quadrifundamental” 5d indecomposable blocks (with flavor group at least SO(4k+2)^3 or SO(4k)^4). \nIn collaboration with M. Del Zotto\, M. Graffeo\, J. Grimminger\, and A. Sangiovanni. \n 
URL:https://cmsa.fas.harvard.edu/event/qft_21025/
LOCATION:Virtual
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QFT-and-Physical-Mathematics-2.10.25-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250210T163000
DTEND;TZID=America/New_York:20250210T173000
DTSTAMP:20260504T015119
CREATED:20240903T195201Z
LAST-MODIFIED:20250130T165640Z
UID:10003438-1739205000-1739208600@cmsa.fas.harvard.edu
SUMMARY:AI in math and theoretical physics: Status and prospects
DESCRIPTION:Colloquium \nSpeaker: Michael Douglas\, Harvard CMSA \nTitle: AI in math and theoretical physics: status and prospects \nAbstract: AI is making great progress and has the potential to change how we work in unprecedented ways. In this talk I will survey a few recent works which illustrate the state of the art\, some from my own research\, some developed at the CMSA’s recent program on Mathematics and Machine Learning. I will then report on current developments in AI and speculate on how they will affect our work in the next few years. \n 
URL:https://cmsa.fas.harvard.edu/event/colloquium-21025/
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-2.10.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250211T110000
DTEND;TZID=America/New_York:20250211T120000
DTSTAMP:20260504T015119
CREATED:20250128T211214Z
LAST-MODIFIED:20250210T141458Z
UID:10003698-1739271600-1739275200@cmsa.fas.harvard.edu
SUMMARY:On the past maximal development of near-FLRW data for the  Einstein scalar-field Vlasov system
DESCRIPTION:General Relativity Seminar \nSpeaker: Liam Urban (University of Vienna) \n\nTitle: On the past maximal development of near-FLRW data for the Einstein scalar-field Vlasov system \nAbstract: In recent years\, the formation of Big Bang singularities has been increasingly well understood in presence of scalar-field matter\, which suppresses the geometric oscillations that one generically expects otherwise. From a cosmological perspective\, however\, one would like to understand whether this feature persists when coupled to further models that more closely resemble the matter content in our universe. \nIn this talk\, I will discuss the past nonlinear stability of FLRW solutions to the Einstein scalar-field Vlasov system in three and four spacetime dimensions without symmetry assumptions. The latter is based on joint work with David Fajman. In both works\, near-FLRW solutions are\nshown to be asymptotically velocity term dominated toward the past\,  resulting in a quiescent Big Bang singularity with stable Kretschmann scalar blow-up. The Vlasov distribution\, however\, becomes highly anisotropic towards the Big Bang singularity\, concentrating in preferred momentum directions associated with eigendirections of the shear. To ensure that the scalar field sufficiently mitigates this behaviour\, one crucially exploits a scaling hierarchy between horizontal and vertical derivatives in the expansion normalized Vlasov equation. In four\nspacetime dimensions\, this analysis is paired with a Bel-Robinson energy formalism to control the spacetime and scalar field evolution\, while one finds a significantly more direct proof in three dimensions since the spatial Riemann curvature is pure trace. \nAs a corollary\, one also obtains that the Strong Cosmic Censorship conjecture holds for four-dimensional polarized $U(1)$-symmetric solutions to the Einstein vacuum equations with spatial topology $M\times\S^1$ and isotropic quotient.
URL:https://cmsa.fas.harvard.edu/event/general-relativity-seminar-21125/
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/1738856087821-8bd46bd5-9d75-4777-80dd-59b2ca5dc8d52025_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250211T161500
DTEND;TZID=America/New_York:20250211T181500
DTSTAMP:20260504T015119
CREATED:20250124T152335Z
LAST-MODIFIED:20250204T212412Z
UID:10003654-1739290500-1739297700@cmsa.fas.harvard.edu
SUMMARY:Discussion of Integrating quantum groups over surfaces
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Ben Gammage\, Harvard University \nTitle: Discussion of Integrating quantum groups over surfaces \nhttps://arxiv.org/abs/1501.04652
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_21125/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-2.11.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250212T120000
DTEND;TZID=America/New_York:20250212T130000
DTSTAMP:20260504T015119
CREATED:20241104T145634Z
LAST-MODIFIED:20250131T154821Z
UID:10003534-1739361600-1739365200@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar: Javier Gomez-Serrano
DESCRIPTION:CMSA Q&A Seminar \nSpeaker: Javier Gomez-Serrano\, Brown University \nTopic: Please tell us about the Millennium prize problem for Navier-Stokes and segue from that into ML?
URL:https://cmsa.fas.harvard.edu/event/cmsaqa_21225/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Q-A-Seminar-2.12.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250212T140000
DTEND;TZID=America/New_York:20250212T150000
DTSTAMP:20260504T015119
CREATED:20250123T194306Z
LAST-MODIFIED:20250228T212617Z
UID:10003661-1739368800-1739372400@cmsa.fas.harvard.edu
SUMMARY:Discovering Data Structures: Nearest Neighbor Search and Beyond
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Omar Salemohamed\, Mila \nTitle: Discovering Data Structures: Nearest Neighbor Search and Beyond \nAbstract: As neural networks learn increasingly sophisticated tasks—from image recognition to mastering the game of Go—we ask: can deep learning discover data structures entirely from scratch? We introduce a general framework for data structure discovery\, which adapts to the underlying data distribution and provides fine-grained control over query and space complexity. For nearest neighbor (NN) search\, our model (re)discovers classic algorithms like binary search in one dimension and learns structures reminiscent of k-d trees and locality-sensitive hashing in higher dimensions. Additionally\, the model learns useful representations of high-dimensional data such as images and exploits them to design effective data structures. Beyond NN search\, we believe the framework could be a powerful tool for data structure discovery for other problems and adapt our framework to the problem of estimating frequencies over a data stream. To encourage future work in this direction\, we conclude with a discussion on some of the opportunities and remaining challenges of learning data structures end-to-end.
URL:https://cmsa.fas.harvard.edu/event/newtech_21225/
LOCATION:Virtual
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-NTM-Seminar-2.12.2025.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250213T100000
DTEND;TZID=America/New_York:20250213T110000
DTSTAMP:20260504T015119
CREATED:20250128T171735Z
LAST-MODIFIED:20250212T182848Z
UID:10003677-1739440800-1739444400@cmsa.fas.harvard.edu
SUMMARY:The Structure of the Flux Landscape
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Damian Van de Heisteeg\, Harvard CMSA \nTitle: The Structure of the Flux Landscape \nAbstract: Identifying flux vacua in string theory with stabilized complex structure moduli presents a significant challenge\, necessitating the minimization of a scalar potential complicated by infinitely many exponential corrections. In order to obtain exact results we connect three central topics: transcendentality or algebraicity of coupling functions\, emergent symmetries\, and the distribution of vacua. We demonstrate these ideas on an explicit example where we determine the landscape of exact flux vacua with a vanishing superpotential. We examine the implications of the tadpole bound\, which intriguingly confines flux vacua to real values of the moduli\, providing a potential avenue for addressing the strong CP problem. \n  \n  \n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_21325/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-2.13.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250213T160000
DTEND;TZID=America/New_York:20250213T170000
DTSTAMP:20260504T015119
CREATED:20240708T151711Z
LAST-MODIFIED:20250328T150436Z
UID:10003396-1739462400-1739466000@cmsa.fas.harvard.edu
SUMMARY:2025 Ding Shum Lecture: Irit Dinur\, IAS: Expanders from local to global
DESCRIPTION:  \n \nOn February 13\, 2025 the CMSA hosted the sixth annual Ding Shum Lecture\, given by Irit Dinur\, Institute for Advanced Study. \nLocation: Harvard Science Center  Hall A & via Zoom Webinar \nSpeaker: Irit Dinur\, Institute for Advanced Study \n\n\n\nTitle: Expanders from local to global \nAbstract: Imagine a network—like a social network\, a transportation system\, or even a biological system—where every part of the network is robustly connected to the rest. Expander graphs are the mathematical idealization of such networks. They are structures where any small group of points (nodes) has many connections to the rest of the graph\, ensuring that no part is isolated and information (or influence) spreads efficiently throughout.\nWe will begin by surveying expander graphs\, their discovery and construction\, and some fascinating applications such as error-correcting codes\, pseudorandomness\, and probabilistically checkable proofs (PCPs)\, highlighting their role as a foundation for many breakthroughs in theoretical computer science. Then\, we will shift focus to an exciting new kind of expanders called high dimensional expanders (HDXs). While expanders are well-understood and widely applied\, HDXs remain enigmatic\, with potential that we are only starting to uncover. We will talk about a fascinating local to global feature that HDXs have\, and some applications. \n\n \n\n\n\n\nThis event is made possible by the generous funding of Ding Lei and Harry Shum.\n\n\n 
URL:https://cmsa.fas.harvard.edu/event/2025_dingshum/
LOCATION:Harvard Science Center\, 1 Oxford Street\, Cambridge\, MA\, 02138
CATEGORIES:Ding Shum Lecture,Event,Public Lecture,Special Lectures
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/DIngShum_21325.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250214T120000
DTEND;TZID=America/New_York:20250214T130000
DTSTAMP:20260504T015119
CREATED:20241211T171913Z
LAST-MODIFIED:20250210T162218Z
UID:10003640-1739534400-1739538000@cmsa.fas.harvard.edu
SUMMARY:Jack polynomials and enumeration of non-orientable maps
DESCRIPTION:Member Seminar \nSpeaker: Houcine Ben Dali\, Harvard CMSA \nTitle: Jack polynomials and enumeration of non-orientable maps \nAbstract: A map is a graph embedded on a surface\, which may be orientable or not. The representation theory of the symmetric group can be used to write the generating series of maps on orientable surfaces using Schur symmetric functions. \nSeveral conjectures suggest that Jack polynomials—a one-parameter deformation of Schur functions—are related to the enumeration of non-orientable maps counted with a “non-orientability” weight. In this talk\, I will discuss some of these conjectures and present recent progress in this direction.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-21425/
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-2.14.25-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250218T110000
DTEND;TZID=America/New_York:20250218T120000
DTSTAMP:20260504T015119
CREATED:20240903T191953Z
LAST-MODIFIED:20250219T144101Z
UID:10003426-1739876400-1739880000@cmsa.fas.harvard.edu
SUMMARY:General Relativity Seminar
DESCRIPTION:General Relativity Seminar \nSpeaker: Maximilian Ofner\, University of Vienna \nTitle: Stability and Instability of Relativistic Fluids in Slowly Expanding Spacetimes \nAbstract: Homogeneous and isotropic solutions to the relativistic Euler equations are known to be unstable on a Minkowski background. However\, for FLRW models with a fast expansion rate\, relativistic fluids stabilize. This scenario suggests a transition between stable and unstable behavior\, somewhere along a family of spacetimes parametrized by their expansion rate. In this talk we will discuss this phase transition for various equations of state\, focusing on the regime of linear and decelerated expansion. This is based on recent analytical results\, complemented by numerical analysis.
URL:https://cmsa.fas.harvard.edu/event/general-relativity-seminar-21825/
LOCATION:Virtual
CATEGORIES:General Relativity Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-GR-Seminar-2.18.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250218T161500
DTEND;TZID=America/New_York:20250218T181500
DTSTAMP:20260504T015119
CREATED:20250124T152555Z
LAST-MODIFIED:20250210T174514Z
UID:10003670-1739895300-1739902500@cmsa.fas.harvard.edu
SUMMARY:Algebras of "symmetries" in QFT and applications to solitons (1)
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Dan Freed\, Harvard CMSA and Math \nTitle:  Algebras of “symmetries” in QFT and applications to solitons (1) \nhttps://arxiv.org/abs/2403.08883
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_21825/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-2.18.2025.1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250219T120000
DTEND;TZID=America/New_York:20250219T130000
DTSTAMP:20260504T015119
CREATED:20241125T204133Z
LAST-MODIFIED:20250210T172019Z
UID:10003623-1739966400-1739970000@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar: Phillip Matchett Wood
DESCRIPTION:CMSA Q&A Seminar \nSpeaker: Phillip Matchett Wood\, Harvard University \nTopic: Info session on the CMSA/Mathematics Summer REU Program (Research Experience for Undergraduates) \n 
URL:https://cmsa.fas.harvard.edu/event/cmsaqa_21925/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Q-A-Seminar-2.19.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250220T100000
DTEND;TZID=America/New_York:20250220T110000
DTSTAMP:20260504T015119
CREATED:20250128T171842Z
LAST-MODIFIED:20250218T155455Z
UID:10003678-1740045600-1740049200@cmsa.fas.harvard.edu
SUMMARY:The geometry of pure spinor superfield formalism 
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Simone Noja (Heidelberg University) \nTitle: The geometry of pure spinor superfield formalism \nAbstract: In this talk I will present a mathematical perspective on the pure spinor superfield formalism. In particular\, I will discuss how field multiplets in supersymmetric theories can be constructed mathematically from geometric data associated with certain algebraic varieties—namely\, the nilpotence variety of the (super)symmetry algebra of the theory. After discussing key examples\, I will\, time permitting\, outline a possible generalization of the formalism within the framework of derived geometry.
URL:https://cmsa.fas.harvard.edu/event/mathphys_22025/
LOCATION:Virtual
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-2.20.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250224T150000
DTEND;TZID=America/New_York:20250224T160000
DTSTAMP:20260504T015119
CREATED:20250128T192220Z
LAST-MODIFIED:20250220T192557Z
UID:10003689-1740409200-1740412800@cmsa.fas.harvard.edu
SUMMARY:Toward constructing a large-scale quantum computer based on TQFT
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Liyuan Chen ( Harvard) \nTitle: Toward constructing a large-scale quantum computer based on TQFT \nAbstract: Topological quantum computation\, motivated by topological quantum field theory (TQFT)\, offers a promising path toward fault-tolerant universal quantum computation. However\, the practical realization of such a system remains challenging due to the difficulty of finding suitable topological materials. In this work\, we provide a comprehensive blueprint for constructing a fault-tolerant universal quantum computer based on the quantum double model $\mathcal{D}(S_3)$\, a specific non-Abelian topological order. We implement logical computations using quantum circuits on qubits and qutrits\, including a single non-Clifford gate\, compatible with near-term quantum devices. This work bridges the gap between abstract mathematical frameworks and noise-resilient quantum computation on near-term devices. Our proposal offers a promising path to realize a non-Abelian anyon-based large scale quantum computer.
URL:https://cmsa.fas.harvard.edu/event/qft_22425/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/1740079272812-56d7a2d6-da58-4464-8ade-b9b1856de79025_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250225T110000
DTEND;TZID=America/New_York:20250225T120000
DTSTAMP:20260504T015119
CREATED:20240903T183821Z
LAST-MODIFIED:20250228T212719Z
UID:10003420-1740481200-1740484800@cmsa.fas.harvard.edu
SUMMARY:BKL bounces outside homogeneity
DESCRIPTION:General Relativity Seminar \nSpeaker: Warren Li ( Princeton University) \nTitle: BKL bounces outside homogeneity \nAbstract: In work spanning the late 20th century\, physicists Belinski\, Khalatnikov and Lifshitz (BKL) proposed a general ansatz for solutions to the Einstein (vacuum) equations near singularities. They suggest that the spacetime dynamics at different spatial points on the singularity decouple and are well-approximated by a system of autonomous nonlinear ODEs\, whose orbits are governed by a chaotic cascade of “BKL bounces”. In this talk\, we present recent work verifying BKL’s heuristics in a large class of symmetric\, but spatially inhomogeneous\, spacetimes. In particular\, we prove decoupling even in the presence of (up to one) BKL bounce. The proof uses nonlinear ODE analysis coupled to hyperbolic energy estimates\, and one hopes our methods may be applied more generally.
URL:https://cmsa.fas.harvard.edu/event/general-relativity-seminar-22525/
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/1740157873632-2128c0f1-4416-42e5-a58b-0475ecffb3852025-1_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250225T161500
DTEND;TZID=America/New_York:20250225T181500
DTSTAMP:20260504T015119
CREATED:20250124T152655Z
LAST-MODIFIED:20250210T174635Z
UID:10003671-1740500100-1740507300@cmsa.fas.harvard.edu
SUMMARY:Algebras of "symmetries" in QFT and applications to solitons (2)
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Dan Freed\, Harvard CMSA and Math \nTitle:  Algebras of “symmetries” in QFT and applications to solitons (2) \nhttps://arxiv.org/abs/2403.08883
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_22525/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-2.25.2025.2.png
END:VEVENT
END:VCALENDAR