BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CMSA - ECPv6.16.3//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:CMSA
X-ORIGINAL-URL:https://cmsa.fas.harvard.edu
X-WR-CALDESC:Events for CMSA
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:America/New_York
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20230312T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20231105T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20240310T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20241103T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20250309T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20251102T060000
END:STANDARD
END:VTIMEZONE
BEGIN:VTIMEZONE
TZID:America/New_York
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20230312T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20231105T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20240310T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20241103T060000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
TZNAME:EDT
DTSTART:20250309T070000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
TZNAME:EST
DTSTART:20251102T060000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240423T123000
DTEND;TZID=America/New_York:20240423T133000
DTSTAMP:20260718T064135
CREATED:20240206T175344Z
LAST-MODIFIED:20240425T205425Z
UID:10000850-1713875400-1713879000@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar 4/23/2024
DESCRIPTION:CMSA Q and A Seminar\n\nSpeaker: Melanie Weber\, Harvard\n\nQuestion: What is the Ricci curvature of a graph?
URL:https://cmsa.fas.harvard.edu/event/cmsaqa-42324/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240426T120000
DTEND;TZID=America/New_York:20240426T130000
DTSTAMP:20260718T064135
CREATED:20240305T160053Z
LAST-MODIFIED:20240416T185829Z
UID:10000691-1714132800-1714136400@cmsa.fas.harvard.edu
SUMMARY:Member Seminar
DESCRIPTION:CMSA Member Seminar \nSpeaker: Matteo Parisi\, Harvard CMSA
URL:https://cmsa.fas.harvard.edu/event/member-seminar-42624/
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:20240429T163000
DTEND;TZID=America/New_York:20240429T173000
DTSTAMP:20260718T064135
CREATED:20240207T190153Z
LAST-MODIFIED:20240424T142108Z
UID:10000818-1714408200-1714411800@cmsa.fas.harvard.edu
SUMMARY:The DNA of Particle Scattering
DESCRIPTION:Colloquium \nSpeaker: Lance Dixon (SLAC\, Stanford University) \nTitle: The DNA of Particle Scattering \nAbstract: At the Large Hadron Collider\, the copious scattering of quarks and gluons in quantum chromodynamics (QCD) produces Higgs bosons and many backgrounds to searches for new physics.  At short distances\, scattering in QCD can be evaluated in perturbation theory and leads to highly intricate\, multivariate mathematical functions such as generalized polylogarithms.  To gain further insight\, one can study a cousin of QCD called planar N=4 super-Yang-Mills theory.  Some processes in this theory can be computed to eighth order in perturbation theory\, versus second or third order in QCD.  The computation and analysis of these results rely on a Hopf algebra coaction on polylogarithms.  Its maximal iteration is called the ‘symbol’\, which serves as a ‘genetic code’ for amplitudes.  The symbol is a linear combination of words\, sequences of letters analogous to sequences of DNA base pairs.  Understanding the alphabet\, and then reading the code\, exposes the physics and mathematics of quantum scattering\, including bizarre new symmetries.  For example\, the two scattering amplitudes that are known to the highest orders in perturbation theory (8 loops) are related to each other by an ‘antipodal duality’\, which involves reading the code backwards as well as forwards. A third scattering amplitude\, which contains the other two as limits\, has an antipodal self-duality which ‘explains’ the other duality.  However\, we still don’t know ‘who ordered’ this property\, or what it really means. \n 
URL:https://cmsa.fas.harvard.edu/event/colloquium-42924/
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-04.29.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240430T123000
DTEND;TZID=America/New_York:20240430T133000
DTSTAMP:20260718T064135
CREATED:20240129T171712Z
LAST-MODIFIED:20240212T155347Z
UID:10000851-1714480200-1714483800@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar 4/30/2024
DESCRIPTION:Speaker: Lakshminarayanan Mahadevan\n\nQuestion: What is morphogenesis? (Morphogenesis: geometry and biology)
URL:https://cmsa.fas.harvard.edu/event/cmsaqa-43024/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240506T163000
DTEND;TZID=America/New_York:20240506T173000
DTSTAMP:20260718T064135
CREATED:20240319T201629Z
LAST-MODIFIED:20240507T201738Z
UID:10000819-1715013000-1715016600@cmsa.fas.harvard.edu
SUMMARY:Liouville Theory and Weil-Petersson Geometry
DESCRIPTION:Colloquium \nSpeaker: Sarah Harrison (Northeastern University) \nTitle: Liouville Theory and Weil-Petersson Geometry \nAbstract: Two-dimensional conformal field theory is a powerful tool to understand the geometry of surfaces. Liouville conformal field theory in the classical (large central charge) limit encodes the geometry of the moduli space of Riemann surfaces. I describe an efficient algorithm to compute the Weil–Petersson metric to arbitrary accuracy using Zamolodchikov’s recursion relation for conformal blocks\, focusing on examples of a sphere with four punctures and generalizations to other one-complex-dimensional moduli spaces. Comparison with analytic results for volumes and geodesic lengths finds excellent agreement. In the case of M_{0\,4}\, I discuss numerical results for eigenvalues of the Weil-Petersson Laplacian and connections with random matrix theory. \nBased on work with K. Coleville\, A. Maloney\, K. Namjou\, and T. Numasawa.
URL:https://cmsa.fas.harvard.edu/event/colloquium-5624/
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-05.06.2024.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240507T120000
DTEND;TZID=America/New_York:20240507T130000
DTSTAMP:20260718T064135
CREATED:20240207T190343Z
LAST-MODIFIED:20240813T155522Z
UID:10000693-1715083200-1715086800@cmsa.fas.harvard.edu
SUMMARY:On using ML for Economics
DESCRIPTION:CMSA Member Seminar \nSpeaker: Sergiy Verstyuk \nTitle: On using ML for Economics \nAbstract: I will introduce some tools from the field of machine learning and discuss how they can be leveraged to get a fresh perspective on economics.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-5724/
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-05.07.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240510T120000
DTEND;TZID=America/New_York:20240510T130000
DTSTAMP:20260718T064135
CREATED:20240416T185907Z
LAST-MODIFIED:20240507T190133Z
UID:10000695-1715342400-1715346000@cmsa.fas.harvard.edu
SUMMARY:On the landscape of 4d N=2 SCFTs
DESCRIPTION:CMSA Member Seminar \nSpeaker: Robert Moscrop\, Harvard CMSA \nTitle: On the landscape of 4d N=2 SCFTs \nAbstract: Four-dimensional conformal field theories with sufficient (N = 2) supersymmetry are highly constrained. So much so\, there has been an ongoing effort to classify them using only information about their moduli space of vacua. In this talk\, I will review recent progress in this classification before detailing a subclass of theories for which the classification problem is particularly tractable.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-51024/
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-05.10.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240513T163000
DTEND;TZID=America/New_York:20240513T173000
DTSTAMP:20260718T064135
CREATED:20240130T151206Z
LAST-MODIFIED:20240508T203329Z
UID:10000814-1715617800-1715621400@cmsa.fas.harvard.edu
SUMMARY:Errors and Correction in Cumulative Knowledge
DESCRIPTION:Colloquium \nSpeaker: Madhu Sudan\, Harvard University \nTitle: Errors and Correction in Cumulative Knowledge \nAbstract: Societal accumulation of knowledge is a complex\, and arguably error-prone\, process. The correctness of new units of knowledge depends not only on the correctness of the new reasoning\, but also on the correctness of old units that the new one builds on. If left unchecked\, errors could completely ruin the validity of most of this knowledge so there must some error-correcting going on. What are the error-corrections processes employed in nature and how effective are they? In this talk\, we describe our attempts to model such phenomena using probablistic models – we describe models for growth of cumulative knowledge\, emergence of errors and methods to check for errors and eliminate them. We then analyze in this compound model\, when effects of errors may survive\, and when they are totally eliminated. \nThe central discovery in our work is the following optimistic statement: If we do checking correctly (most of the time) investing just a constant factor (<1) of our effort in checking (and saving the remaining constant factor towards deriving new units of knowledge)\, then effects of errors can be kept in check. Notably the amount of effort expended on checking does not scale with the volume of total knowledge or the depth of dependencies in the new units of knowledge\, either of which would be overwhelming. \nBased on the papers: \nIs this correct? Let’s check!\nOmri Ben-Eliezer\, Dan Mikulincer\, Elchanan Mossel\, Madhu Sudan\narXiv:2211.12301 \nErrors are Robustly Tamed in Cumulative Knowledge Processes\nAnna Brandenberger\, Cassandra Marcussen\, Elchanan Mossel\, Madhu Sudan\narXiv:2309.05638
URL:https://cmsa.fas.harvard.edu/event/colloquium-4124/
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-05.13.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240514T123000
DTEND;TZID=America/New_York:20240514T133000
DTSTAMP:20260718T064135
CREATED:20240424T200426Z
LAST-MODIFIED:20240510T202406Z
UID:10003382-1715689800-1715693400@cmsa.fas.harvard.edu
SUMMARY:Quasilocal mass for general domains in space
DESCRIPTION:CMSA Member Seminar \nSpeaker: Jue Liu \nTitle: Quasilocal mass for general domains in space \nAbstract: Diffeomorphism-invariant quasilocal mass in classical general relativity has been studied for decades\, but it is still an open problem how to define quasi-local mass for general domains with multiple boundaries in space. Using the Hamiltonian formulation\, we will provide a new way to define the nonnegative quasi-local mass\, and give recent progress in overcoming the difficulties.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-51424/
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-05.14.24.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240909T163000
DTEND;TZID=America/New_York:20240909T173000
DTSTAMP:20260718T064135
CREATED:20240827T200454Z
LAST-MODIFIED:20240903T152309Z
UID:10003406-1725899400-1725903000@cmsa.fas.harvard.edu
SUMMARY:Combinatorics and geometry of the amplituhedron
DESCRIPTION:Colloquium \nSpeaker: Lauren Williams\, Harvard University \nTitle: Combinatorics and geometry of the amplituhedron \nAbstract: The amplituhedron is a geometric object introduced by Arkani-Hamed and Trnka to compute scattering amplitudes in N=4 super Yang Mills theory. It generalizes interesting objects such as cyclic polytopes and the positive Grassmannian. It has connections to tropical geometry\, cluster algebras\, and combinatorics (plane partitions\, Catalan numbers). I’ll give a gentle introduction to the amplituhedron\, then survey some recent progress on some of the main conjectures about the amplituhedron: the Magic Number Conjecture\, the BCFW tiling conjecture\, and the Cluster Adjacency conjecture.  Based on joint works withEvan-Zohar\, Lakrec\, Parisi\, Sherman-Bennett\, and Tessler.
URL:https://cmsa.fas.harvard.edu/event/colloquium_9924/
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-09.09.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240910T160000
DTEND;TZID=America/New_York:20240910T180000
DTSTAMP:20260718T064135
CREATED:20240905T130004Z
LAST-MODIFIED:20240910T150123Z
UID:10003443-1725984000-1725991200@cmsa.fas.harvard.edu
SUMMARY:BPS Algebras in Landau-Ginzburg Models
DESCRIPTION:Speaker: Ahsan Khan (CMSA) \nTitle: BPS Algebras in Landau-Ginzburg Models \nAbstract: The study of BPS states in supersymmetric quantum field theory has been a fruitful source of both mathematical and physical insights. In particular their study often leads to rich algebraic structures – from the “Algebra of the Infrared” of Gaiotto-Moore-Witten to the “Cohomological Hall Algebras” of Kontsevich-Soibelman. In this talk\, I will provide an overview of some of these algebraic constructions\, with a particular emphasis on BPS states in two-dimensional Landau-Ginzburg models. In the second half of the talk\, I will discuss how these algebraic structures can be extended to more general Landau-Ginzburg models defined by closed holomorphic one-forms.
URL:https://cmsa.fas.harvard.edu/event/geometry-and-quantum-theory-seminar_91024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-09.10.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240913T120000
DTEND;TZID=America/New_York:20240913T130000
DTSTAMP:20260718T064135
CREATED:20240907T183113Z
LAST-MODIFIED:20240911T193907Z
UID:10003414-1726228800-1726232400@cmsa.fas.harvard.edu
SUMMARY:Abundance for mixed characteristic threefolds
DESCRIPTION:Member Seminar \nSpeaker: Iacopo Brivio (CMSA) \nTitle: Abundance for mixed characteristic threefolds \nAbstract: The Minimal Model Program (MMP) predicts that every algebraic variety X is birational to either a fibration in Fano varieties\, or it admits a “minimal model” X’\, that is a birational model with nef canonical bundle K_X’. The Abundance conjecture predicts then that K_X’ is actually semiample\, in particular it endows X’ with the structure of a Calabi-Yau fibration. These conjectures were initially phrased for complex varieties\, but more recently there has been a lot of interest in working over positive characteristic fields\, or even mixed characteristic rings. In this talk I will give a broad overview of the subject\, starting from the case of complex surfaces. In the last part I will outline a proof of the Abundance conjecture for mixed characteristic threefolds (based on joint work with F. Bernasconi and L. Stigant).
URL:https://cmsa.fas.harvard.edu/event/member-seminar_91324/
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-09.13.24.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240913T143000
DTEND;TZID=America/New_York:20240913T170000
DTSTAMP:20260718T064135
CREATED:20240723T202450Z
LAST-MODIFIED:20240911T134726Z
UID:10003401-1726237800-1726246800@cmsa.fas.harvard.edu
SUMMARY:Freedman CMSA Seminar
DESCRIPTION:Freedman CMSA Seminar \n  \n2:00-3:30 pm ET \nSpeaker: Mike Freedman\, Harvard CMSA \nTitle: Detecting hidden structures in linear maps \nAbstract: I’ll consider the problem of detecting spectral features and tensor structures within linear maps both in a quantum and classical contexts. In the quantum context there is the question of whether a Hamiltonian is local\, and if so\, local in distinct coordinate systems (a “duality”). Also\, in the case of a unitary described by a quantum circuit\, does it possess unusual spectral features or tensor structure? In ML one optimizes many linear maps. How would we know – and would we care – if the resulting maps (approximately) tensor factored? \n  \n3:30-4:00 pm ET \nBreak/Discussion \n  \n4:00-5:30 pm ET \nSpeaker: Ryan O’Donnell\, Carnegie Mellon University \nTitle: Quartic quantum speedups for planted inference \nAbstract: Consider the following task (“noisy 4XOR”)\, arising in CSPs\, optimization\, and cryptography. There is a ‘secret’ Boolean vector x in {-1\,+1}^n. One gets m randomly chosen pairs (S\, b)\, where S is a set of 4 coordinates from [n] and b is x^S := prod_{i in S} x_i with probability 1-eps\, and -x^S with probability eps. Can you tell the difference between the cases eps = 0.1 and eps = 0.5? \nIt depends on m. The best known algorithms use the “Kikuchi method” and run in time ~n^L when m ~ n^2/L. We will review this method\, and also show that the running time can be improved to roughly n^{L/4} with a quantum algorithm. \nJoint work with Alexander Schmidhuber (MIT)\, Robin Kothari (Google)\, and Ryan Babbush (Google).
URL:https://cmsa.fas.harvard.edu/event/freedman_91324/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Freedman Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Freedman-Seminar-09.13.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240916T093000
DTEND;TZID=America/New_York:20240916T103000
DTSTAMP:20260718T064135
CREATED:20240907T170536Z
LAST-MODIFIED:20240912T174105Z
UID:10003445-1726479000-1726482600@cmsa.fas.harvard.edu
SUMMARY:Ringdown in the SYK model
DESCRIPTION:Joint BHI/CMSA Foundation Seminar \nSpeaker: Matthew Dodelson (Harvard) \nTitle: Ringdown in the SYK model \nAbstract: Thermal correlators in large N systems equilibrate at late times\, but the precise late-time behavior is unknown away from holographic and free field limits. In this talk I will analyze this problem in the case of the SYK model away from the low-temperature limit. The basic technique is a resummation of perturbation theory which is reminiscent of the double cone construction. We will also discuss the interpretation of the result in terms of a dual stringy black hole.
URL:https://cmsa.fas.harvard.edu/event/foundation_91624/
LOCATION:CMSA Room G10\, 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-09.16.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240916T163000
DTEND;TZID=America/New_York:20240916T173000
DTSTAMP:20260718T064135
CREATED:20240903T193540Z
LAST-MODIFIED:20240916T163127Z
UID:10003430-1726504200-1726507800@cmsa.fas.harvard.edu
SUMMARY:Periodic pencils of flat connections and their p-curvature
DESCRIPTION:Colloquium \nSpeaker: Pavel Etingof (MIT) \nTitle: Periodic pencils of flat connections and their p-curvature \n A periodic pencil of flat connections on a smooth algebraic variety  is a linear family of flat connections  \, where  are local coordinates on  and  are matrix-valued regular functions. A pencil is periodic if it is generically invariant under the shifts  up to isomorphism. I will explain that periodic pencils have many remarkable properties\, and there are many interesting examples of them\, e.g. Knizhnik-Zamolodchikov\, Dunkl\, Casimir connections and equivariant quantum connections for conical symplectic resolutions with finitely many torus fixed points. I will also explain that in characteristic \, the -curvature operators  of a periodic pencil  are isospectral to the commuting endomorphisms \, where  is the Frobenius twist of . This allows us to compute the eigenvalues of the -curvature for the above examples\, and also to show that a periodic pencil of connections always has regular singularites. This is joint work with Alexander Varchenko. \n(Abstract link (pdf)
URL:https://cmsa.fas.harvard.edu/event/colloquium_91624/
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-09.16.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240917T160000
DTEND;TZID=America/New_York:20240917T180000
DTSTAMP:20260718T064135
CREATED:20240907T170124Z
LAST-MODIFIED:20240916T162843Z
UID:10003411-1726588800-1726596000@cmsa.fas.harvard.edu
SUMMARY:Mathematics around Twisted Holography
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Keyou Zeng (CMSA) \nTitle: Mathematics around Twisted Holography \nAbstract: The holography principle is an important idea in physics and has been widely studied since the 90s. Twisted holography offers a way to simplify physical holography models through the procedure called twisting. In the first part of the talk\, I’ll introduce some of the mathematical structures underlying this twisted version of holography\, such as Koszul duality. \nIn the second part\, I’ll discuss the concept of vertex algebras in symmetric monoidal categories\, specifically in Deligne category. This framework will serve as a tool to rigorously define the “large N” algebra that emerges from twisted holography. \n 
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_91724/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-09.17.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240918T120000
DTEND;TZID=America/New_York:20240918T130000
DTSTAMP:20260718T064135
CREATED:20240907T160427Z
LAST-MODIFIED:20240924T195406Z
UID:10003409-1726660800-1726664400@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar: Noam Elkies
DESCRIPTION:CMSA Q&A Seminar \nSpeaker: Noam Elkies\, Harvard Math \nTopic: How to show E8 and Leech lattices have optimal sphere packings?
URL:https://cmsa.fas.harvard.edu/event/cmsaqa_91824/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240920T120000
DTEND;TZID=America/New_York:20240920T130000
DTSTAMP:20260718T064135
CREATED:20240907T183145Z
LAST-MODIFIED:20240916T164559Z
UID:10003462-1726833600-1726837200@cmsa.fas.harvard.edu
SUMMARY:Communication Complexity of Combinatorial Auctions
DESCRIPTION:Member Seminar \nSpeaker: Tomer Ezra (CMSA) \nTitle: Communication Complexity of Combinatorial Auctions \nAbstract: We study the communication complexity of welfare maximization in combinatorial auctions with m items and two subadditive bidders. A 2-approximation can be guaranteed by a trivial randomized protocol with zero communication\, or a trivial deterministic protocol with O(1) communication. We show that outperforming these trivial protocols requires exponential communication\, settling an open question of [DobzinskiNS10\, Feige09]. \nSpecifically\, we show that any (randomized) protocol guaranteeing a o(logm)-approximation requires communication exponential in m. We complement it by presenting an O(logm)-approximation in poly(m) communication.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-92024/
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-09.20.24.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240920T140000
DTEND;TZID=America/New_York:20240920T153000
DTSTAMP:20260718T064135
CREATED:20240907T191849Z
LAST-MODIFIED:20240918T134041Z
UID:10003467-1726840800-1726846200@cmsa.fas.harvard.edu
SUMMARY:Classification and Construction of crystalline topological superconductors and insulators in interacting fermion systems
DESCRIPTION:Quantum Matter Seminar \nSpeaker: Zhengcheng Gu\, Chinese University of Hong Kong \nTitle: Classification and construction of crystalline topological superconductors and insulators in interacting fermion systems \nAbstract: The construction and classification of crystalline symmetry protected topological (SPT) phases in interacting bosonic and fermionic systems have been intensively studied in the past few years. Crystalline SPT phases are not only of conceptual importance\, but also provide us great opportunities towards experimental realization since space group symmetries naturally exist for any realistic material. In this talk\, I will discuss how to construct and classify crystalline topological superconductors (TSC) and topological insulators (TI) in interacting fermion systems. I will also discuss the relationship between internal symmetry protected SPT phases and crystalline symmetry protected SPT Phases.
URL:https://cmsa.fas.harvard.edu/event/qm_92024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics,Quantum Matter
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QMMP-09.20.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240923T163000
DTEND;TZID=America/New_York:20240923T173000
DTSTAMP:20260718T064135
CREATED:20240903T194207Z
LAST-MODIFIED:20240918T190927Z
UID:10003431-1727109000-1727112600@cmsa.fas.harvard.edu
SUMMARY:Symmetry groups in infinite dimensions
DESCRIPTION:Colloquium \nSpeaker: Lisa Carbone\, Rutgers University \nTitle: Symmetry groups in infinite dimensions \nAbstract: The study of many physical theories requires an understanding of symmetries of infinite dimensional Lie algebras. The construction of groups of automorphisms for infinite dimensional Lie algebras is challenging\, but there is well established theory for the class of Kac-Moody algebras. A generalization of Kac-Moody algebras known as Borcherds algebras arise in string theory models\, but the methods for constructing Kac-Moody groups break down for this more general class. We discuss the challenges that arise and describe several approaches to constructing groups for Borcherds algebras. Our main example is the Monster Lie algebra which plays an important role in the solution of Monstrous Moonshine and which is a symmetry algebra of a model of the compactified Heterotic String.
URL:https://cmsa.fas.harvard.edu/event/colloquium-92324/
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-09.23.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240924T161500
DTEND;TZID=America/New_York:20240924T181500
DTSTAMP:20260718T064135
CREATED:20240907T180814Z
LAST-MODIFIED:20240924T145311Z
UID:10003455-1727194500-1727201700@cmsa.fas.harvard.edu
SUMMARY:Symplectic duality in examples
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Vasily Krylov\, Harvard CMSA & Math \nTitle: Symplectic duality in examples \nAbstract: Over the past twenty years\, mathematicians and physicists have shown increasing interest in studying certain Poisson varieties\, known as “symplectic singularities.” Many of these objects naturally arise as Higgs or Coulomb branches of certain TQFTs and\, therefore\, fall within the framework of 3D mirror symmetry\, also known as symplectic duality. The first part of the talk will provide a gentle introduction to the theory of symplectic singularities\, with an emphasis on various examples. In the second part\, we will discuss how the symplectic duality works in examples\, beginning with the simplest cases. We will then discuss a particular phenomenon called the Hikita-Nakajima conjecture\, which predicts a deep and nontrivial relationship between dual varieties. It is particularly intriguing that this conjecture was formulated by mathematicians and still requires further understanding from a physical perspective.
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_92424/
LOCATION:Science Center Hall E\, 1 Oxford Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-09.24.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240925T140000
DTEND;TZID=America/New_York:20240925T150000
DTSTAMP:20260718T064135
CREATED:20240907T180716Z
LAST-MODIFIED:20241002T144226Z
UID:10003454-1727272800-1727276400@cmsa.fas.harvard.edu
SUMMARY:Infinite Limits and Scaling Laws for Deep Neural Networks
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Blake Bordelon \nTitle: Infinite Limits and Scaling Laws for Deep Neural Networks \nAbstract: Scaling up the size and training horizon of deep learning models has enabled breakthroughs in computer vision and natural language processing. Empirical evidence suggests that these neural network models are described by regular scaling laws where performance of finite parameter models improves as model size increases\, eventually approaching a limit described by the performance of an infinite parameter model. In this talk\, we will first examine certain infinite parameter limits of deep neural networks which preserve representation learning and then describe how quickly finite models converge to these limits. Using dynamical mean field theory methods\, we provide an asymptotic description of the learning dynamics of randomly initialized infinite width and depth networks. Next\, we will empirically investigate how close the training dynamics of finite networks are to these idealized limits. Lastly\, we will provide a theoretical model of neural scaling laws which describes how generalization depends on three computational resources: training time\, model size and data quantity. This theory allows analysis of compute optimal scaling strategies and predicts how model size and training time should be scaled together in terms of spectral properties of the limiting kernel. The theory also predicts how representation learning can improve neural scaling laws in certain regimes. For very hard tasks\, the theory predicts that representation learning can approximately double the training-time exponent compared to the static kernel limit.
URL:https://cmsa.fas.harvard.edu/event/newtech_92524/
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-9.25.24.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240927T090000
DTEND;TZID=America/New_York:20240927T100000
DTSTAMP:20260718T064135
CREATED:20240907T180338Z
LAST-MODIFIED:20240924T144003Z
UID:10003413-1727427600-1727431200@cmsa.fas.harvard.edu
SUMMARY:Going to the other side .... in algebra\, topology\, and maybe physics
DESCRIPTION:Quantum Field Theory and Physical Mathematics \nSpeaker: Sergei Gukov (Caltech)\n\nTitle: Going to the other side …. in algebra\, topology\, and maybe physics\n\nAbstract: Inspired by Eugene Wigner’s reflections on the ‘unreasonable effectiveness of mathematics in the natural sciences\,’ this talk is about the surprising and pervasive role of a peculiar phenomenon that\, a priori\, seemed to have no reason to exist. Yet\, it emerges across many different areas of mathematics and theoretical physics\, including: \n\nthe Kazhdan-Lusztig correspondence\nquantum invariants of 3-manifolds\nthe study of 2d (0\,2) boundary conditions in 3d N=2 theories\nresurgent analysis\n\nAlthough each of these fields approaches the phenomenon from a different perspective\, the results align in striking and unexpected ways. \n\n 
URL:https://cmsa.fas.harvard.edu/event/qm_92724/
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-09.27.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241001T161500
DTEND;TZID=America/New_York:20241001T181500
DTSTAMP:20260718T064135
CREATED:20240916T141133Z
LAST-MODIFIED:20240927T182238Z
UID:10003506-1727799300-1727806500@cmsa.fas.harvard.edu
SUMMARY:Topological Invariants of gapped states through cosheaves
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Bowen Yang\, Harvard CMSA \nTitle: Topological Invariants of gapped states through cosheaves \nAbstract: We provide a proper mathematical framework for the constructions of topological invariants of gapped quantum states and interpret topological invariants of gapped states as lattice analogs of ’t Hooft anomalies in Quantum Field Theory. Our secondary goal is to generalize this construction in various directions. In particular\, we show how to define topological invariants of lattice spin systems living on well-behaved subsets of the lattice.
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_10124/
LOCATION:Science Center Hall E\, 1 Oxford Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-10.1.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241002T120000
DTEND;TZID=America/New_York:20241002T130000
DTSTAMP:20260718T064135
CREATED:20240907T160557Z
LAST-MODIFIED:20240924T194207Z
UID:10003450-1727870400-1727874000@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar: Cliff Taubes
DESCRIPTION:CMSA Q&A Seminar \nSpeaker: Cliff Taubes\, Harvard Mathematics \nTopic: What are Z/2 harmonic 1-forms?
URL:https://cmsa.fas.harvard.edu/event/cmsaqa_10224/
LOCATION:MA
CATEGORIES:CMSA Q&A Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241002T140000
DTEND;TZID=America/New_York:20241002T150000
DTSTAMP:20260718T064135
CREATED:20240907T180645Z
LAST-MODIFIED:20241002T195652Z
UID:10003453-1727877600-1727881200@cmsa.fas.harvard.edu
SUMMARY:Hierarchical data structures through the lenses of diffusion models
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Antonio Sclocchi\, EPFL \nTitle: Hierarchical data structures through the lenses of diffusion models \nAbstract: The success of deep learning with high-dimensional data relies on the fact that natural data are highly structured. A key aspect of this structure is hierarchical compositionality\, yet quantifying it remains a challenge. \nIn this talk\, we explore how diffusion models can serve as a tool to probe the hierarchical structure of data. We consider a context-free generative model of hierarchical data and show the distinct behaviors of high- and low-level features during a noising-denoising process. Specifically\, we find that high-level features undergo a sharp transition in reconstruction probability at a specific noise level\, while low-level features recombine into new data from different classes. This behavior of latent features leads to correlated changes in real-space variables\, resulting in a diverging correlation length at the transition. \nWe validate these predictions in experiments with real data\, using state-of-the-art diffusion models for both images and texts. Remarkably\, both modalities exhibit a growing correlation length in changing features at the transition of the noising-denoising process. \nOverall\, these results highlight the potential of hierarchical models in capturing non-trivial data structures and offer new theoretical insights for understanding generative AI.
URL:https://cmsa.fas.harvard.edu/event/newtech_10224/
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-10.2.24.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241004T090000
DTEND;TZID=America/New_York:20241004T103000
DTSTAMP:20260718T064135
CREATED:20240907T190416Z
LAST-MODIFIED:20240930T173743Z
UID:10003465-1728032400-1728037800@cmsa.fas.harvard.edu
SUMMARY:Holography and Regge Phases at Large U(1) Charge
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Giulia Fardelli\, Boston University \nTitle: Holography and Regge Phases at Large U(1) Charge \nAbstract: A single Conformal Field Theory (CFT) can have a rich phase diagram with qualitatively different emergent behaviors in a range of different regimes parameterized by the conserved charges of the theory. In this talk\, I will consider a CFT with a global U(1) current and explore the phase diagram as a function of the U(1) charge Q and angular momentum J\, particularly at large J and Q. By taking the large J limit first\, we are able to employ a dual holographic interpretation in AdS_{d+1} to predict the energy spectrum of Q-particle states. This limit has been studied in detail for Q=2\, yielding very general results applicable to unitary CFTs in d>2. When Q is also taken to be large\, the description is more complicated; nevertheless\, we can draw interesting conclusions about the energy spectrum under certain assumptions. I will conclude with a concrete example\, the O(2) model in 3d\, highlighting interesting connections with recent (and less recent) results in this context. \n 
URL:https://cmsa.fas.harvard.edu/event/qm_10424/
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-10.4.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241004T120000
DTEND;TZID=America/New_York:20241004T130000
DTSTAMP:20260718T064135
CREATED:20240907T183353Z
LAST-MODIFIED:20240930T155114Z
UID:10003464-1728043200-1728046800@cmsa.fas.harvard.edu
SUMMARY:High-dimensional learning of narrow neural networks
DESCRIPTION:Member Seminar \nSpeaker: Hugo Cui\, CMSA \nTitle: High-dimensional learning of narrow neural networks \nAbstract: This talk explores the interplay between neural network architectures and data structure through the lens of high-dimensional asymptotics. We focus on a class of narrow neural networks\, namely networks possessing a finite number of hidden units\, while operating in high dimensions. In the limit of large data dimension and comparably large number of samples\, we derive a tight asymptotic characterization of the learning of these architectures. As an illustration\, we discuss how this characterization enables the analysis of a solvable model of dot-product attention. We show how the latter can learn to implement either a positional attention mechanism (with tokens attending to each other based on their respective positions)\, or a semantic attention mechanism (with tokens attending to each other based on their meaning)\, and evidence a phase transition with sample complexity from positional to semantic learning.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-10424/
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-10.4.24.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241007T163000
DTEND;TZID=America/New_York:20241007T173000
DTSTAMP:20260718T064135
CREATED:20240903T194924Z
LAST-MODIFIED:20241003T160128Z
UID:10003433-1728318600-1728322200@cmsa.fas.harvard.edu
SUMMARY:Local complexity measures in modern parameterized function classes for supervised learning
DESCRIPTION:Colloquium \nSpeaker: Elisenda Grigsby\, Boston College \nTitle: Local complexity measures in modern parameterized function classes for supervised learning \nAbstract: The parameter space for any fixed architecture of neural networks serves as a proxy during training for the associated class of functions – but how faithful is this representation? For any fixed feedforward ReLU network architecture\, it is well-known that many different parameter settings can determine the same function. It is less well-known that the degree of this redundancy is inhomogeneous across parameter space. I’ll discuss two locally-applicable complexity measures for ReLU network classes and what we know about the relationship between them: (1) the local functional dimension\, and (2) a local version of VC dimension called persistent pseudodimension. The former is easy to compute on finite batches of points\, the latter should give local bounds on the generalization gap. I’ll speculate about how this circle of ideas might help guide our understanding of the double descent phenomenon. All of the work described in this talk is joint with Kathryn Lindsey. Some portions are also joint with Rob Meyerhoff\, David Rolnick\, and Chenxi Wu.
URL:https://cmsa.fas.harvard.edu/event/colloquium-10724/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=application/pdf:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.7.2024.docx.pdf
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241008T161500
DTEND;TZID=America/New_York:20241008T181500
DTSTAMP:20260718T064135
CREATED:20240917T160554Z
LAST-MODIFIED:20241004T150540Z
UID:10003509-1728404100-1728411300@cmsa.fas.harvard.edu
SUMMARY:Skein traces and curve counting
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Sunghyuk Park\, Harvard CMSA \nTitle: Skein traces and curve counting \nAbstract: Skein modules are vector space-valued invariants of 3-manifolds describing the space of line defects modulo skein relations (determined by a choice of a ribbon category). When the 3-manifold is S x I for some surface S\, the skein module has a natural algebra structure and is called the skein algebra of S. \nIn 2010\, Bonahon and Wong constructed an algebra embedding (named “quantum trace”) of the sl_2 skein algebra into a quantum cluster variety called the “quantum Teichmuller space” for punctured surfaces\, which has applications to the representation theory of skein algebras. \nIn the first half of this talk\, I will give an overview of these concepts and explain how the quantum trace map can be generalized to the 3-dimensional setup. \nIn the second half\, I will discuss how everything above can be generalized to HOMFLYPT skeins and has natural interpretation in terms of counts of holomorphic curves.
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_10824/
LOCATION:Science Center Hall E\, 1 Oxford Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-10.8.2024.png
END:VEVENT
END:VCALENDAR