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DTSTART;TZID=America/New_York:20210928T130000
DTEND;TZID=America/New_York:20210928T130000
DTSTAMP:20260511T141101
CREATED:20240214T045955Z
LAST-MODIFIED:20240304T060348Z
UID:10002535-1632834000-1632834000@cmsa.fas.harvard.edu
SUMMARY:9/28/2021 Combinatorics\, Physics and Probability Seminar
DESCRIPTION:Title: The hypersimplex and the m=2 amplituhedron \nAbstract: I’ll discuss a curious correspondence between the m=2 amplituhedron\, a 2k-dimensional subset of Gr(k\, k+2)\, and the hypersimplex\, an (n-1)-dimensional polytope in R^n. The amplituhedron and hypersimplex are both images of the totally nonnegative Grassmannian under some map (the amplituhedron map and the moment map\, respectively)\, but are different dimensions and live in very different ambient spaces. I’ll talk about joint work with Matteo Parisi and Lauren Williams in which we give a bijection between decompositions of the amplituhedron and decompositions of the hypersimplex (originally conjectured by Lukowski–Parisi–Williams). Along the way\, we prove the sign-flip description of the m=2 amplituhedron conjectured by Arkani-Hamed–Thomas–Trnka and give a new decomposition of the m=2 amplituhedron into Eulerian-number-many chambers (inspired by an analogous hypersimplex decomposition).
URL:https://cmsa.fas.harvard.edu/event/9-28-2021-combinatorics-physics-and-probability-seminar/
CATEGORIES:Combinatorics Physics and Probability
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210928T130000
DTEND;TZID=America/New_York:20210928T140000
DTSTAMP:20260511T141101
CREATED:20240214T054256Z
LAST-MODIFIED:20240304T064006Z
UID:10002542-1632834000-1632837600@cmsa.fas.harvard.edu
SUMMARY:The Mirror Clemens-Schmid Sequence
DESCRIPTION:Abstract: I will present a four-term exact sequence relating the cohomology of a fibration to the cohomology of an open set obtained by removing the preimage of a general linear section of the base. This exact sequence respects three filtrations\, the Hodge\, weight\, and perverse Leray filtrations\, so that it is an exact sequence of mixed Hodge structures on the graded pieces of the perverse Leray filtration. I claim that this sequence should be thought of as a mirror to the Clemens-Schmid sequence describing the structure of a degeneration and formulate a “mirror P=W” conjecture relating the filtrations on each side. Finally\, I will present evidence for this conjecture coming from the K3 surface setting. This is joint work with Charles F. Doran.
URL:https://cmsa.fas.harvard.edu/event/the-mirror-clemens-schmid-sequence/
CATEGORIES:Algebraic Geometry in String Theory Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210929T114800
DTEND;TZID=America/New_York:20210929T134800
DTSTAMP:20260511T141101
CREATED:20240214T090955Z
LAST-MODIFIED:20240301T093415Z
UID:10002610-1632916080-1632923280@cmsa.fas.harvard.edu
SUMMARY:Oscillations in the thermal conductivity of a spin liquid*
DESCRIPTION:Title: Oscillations in the thermal conductivity of a spin liquid* \nAbstract: The layered honeycomb magnet alpha-RuCl3 orders below 7 K in a zigzag phase in zero field. An in-plane magnetic field H||a suppresses the zigzag order at 7 Tesla\, leaving a spin-disordered phase widely believed to be a quantum spin liquid (QSL) that extends to ~12 T. We have observed oscillations in the longitudinal thermal conductivity Kxx vs. H from 0.4 to 4 K. The oscillations are periodic in 1/H (with a break-in-slope at 7 T). The amplitude function is maximal in the QSL phase (7 –11.5 T). I will describe a benchmark for crystalline disorder\, the reproducibility and intrinsic nature of the oscillations\, and discuss implications for the QSL state. I will also show detailed data on the thermal Hall conductivity Kxy measured from 0.4 K to 10 K and comment on recent half-quantization results. \n*Czajka et al.\, Nature Physics 17\, 915 (2021). \nCollaborators: Czajka\, Gao\, Hirschberger\, Lampen Kelley\, Banerjee\, Yan\, Mandrus and Nagler.
URL:https://cmsa.fas.harvard.edu/event/9-29-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210929T150000
DTEND;TZID=America/New_York:20210929T160000
DTSTAMP:20260511T141101
CREATED:20240214T092650Z
LAST-MODIFIED:20240517T200354Z
UID:10002626-1632927600-1632931200@cmsa.fas.harvard.edu
SUMMARY:Constructions in combinatorics via neural networks
DESCRIPTION:Speaker: Adam Wagner\, Tel Aviv University \nTitle: Constructions in combinatorics via neural networks \nAbstract: Recently\, significant progress has been made in the area of machine learning algorithms\, and they have quickly become some of the most exciting tools in a scientist’s toolbox. In particular\, recent advances in the field of reinforcement learning have led computers to reach superhuman level play in Atari games and Go\, purely through self-play. In this talk I will give a very basic introduction to neural networks and reinforcement learning algorithms. I will also indicate how these methods can be adapted to the ““game” of trying to find a counterexample to a mathematical conjecture\, and show some examples where this approach was successful.
URL:https://cmsa.fas.harvard.edu/event/9-29-2021-new-technologies-in-mathematics-seminar/
CATEGORIES:New Technologies in Mathematics Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210929T171500
DTEND;TZID=America/New_York:20210929T181500
DTSTAMP:20260511T141101
CREATED:20240214T055645Z
LAST-MODIFIED:20240304T065421Z
UID:10002546-1632935700-1632939300@cmsa.fas.harvard.edu
SUMMARY:Langlands duality for 3 manifolds
DESCRIPTION:Speaker: David Jordan (U Edinburgh) \nTitle: Langlands duality for 3 manifolds \nAbstract: Langlands duality began as a deep and still mysterious conjecture in number theory\, before branching into a similarly deep and mysterious conjecture of Beilinson and Drinfeld concerning the algebraic geometry of Riemann surfaces. In this guise it was given a physical explanation in the framework of 4-dimensional super symmetric quantum field theory by Kapustin and Witten.  However to this day the Hilbert space attached to 3-manifolds\, and hence the precise form of Langlands duality for them\, remains a mystery. \nIn this talk I will propose that so-called “skein modules” of 3-manifolds give natural candidates for these Hilbert spaces at generic twisting parameter Psi \, and I will explain a Langlands duality in this setting\, which we have conjectured with Ben-Zvi\, Gunningham and Safronov. \nIntriguingly\, the precise formulation of such a conjecture in the classical limit Psi=0 is still an open question\, beyond the scope of the talk.
URL:https://cmsa.fas.harvard.edu/event/langlands-duality-for-3-manifolds/
LOCATION:Virtual
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-09.29.21.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20210930T130000
DTEND;TZID=America/New_York:20210930T143000
DTSTAMP:20260511T141101
CREATED:20230824T171544Z
LAST-MODIFIED:20240304T084438Z
UID:10001305-1633006800-1633012200@cmsa.fas.harvard.edu
SUMMARY:Cytoskeletal Energetics and Energy Metabolism
DESCRIPTION:Abstract: Life is a nonequilibrium phenomenon. Metabolism provides a continuous flux of energy that dictates the form and function of many subcellular structures. These subcellular structures are active materials\, composed of molecules which use chemical energy to perform mechanical work and locally violate detailed balance. One of the most dramatic examples of such a self-organizing structure is the spindle\, the cytoskeletal based assembly which segregates chromosomes during cell division. Despite its central role\, very little is known about the nonequilibrium thermodynamics of active subcellular matter\, such as the spindle. In this talk\, I will describe ongoing work from my lab aimed at understanding the flows of energy which drive the nonequilibrium behaviors of the cytoskeleton in vitro and in vivo.
URL:https://cmsa.fas.harvard.edu/event/cytoskeletal-energetics-and-energy-metabolism/
CATEGORIES:Active Matter Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211001T093000
DTEND;TZID=America/New_York:20211001T103000
DTSTAMP:20260511T141101
CREATED:20240214T074545Z
LAST-MODIFIED:20240301T111944Z
UID:10002569-1633080600-1633084200@cmsa.fas.harvard.edu
SUMMARY:Instability of naked singularities in general relativity
DESCRIPTION:Member Seminar \nSpeaker: Jue Liu \nTitle: Instability of naked singularities in general relativity \nAbstract: One of the fundamental problems in mathematical relativity is the weak cosmic censorship conjecture\, proposed by Penrose\, which roughly states that for generic physical spacetime\, the singularities (if existed) must be hidden behind the black holes. Unfortunately\, the singularities visible to faraway observers\, which are called by naked singularities\, indeed exist. The first example constructed by Christodoulou in 1994 is a family of self-similar spherically symmetric spacetime\, in which the naked singularity forms due to a self-gravitating scalar field. Therefore the suitable censorship conjecture should be reduced to prove the instability of the naked singularities. In 1999 Christodoulou succeeded to prove the weak cosmic censorship conjecture in spherically symmetric cases\, and recently the co-author and I found that the corresponding results have a big probability to be extended to spacetime without symmetries. In this talk I will discuss how to prove the instability of naked singularities using the energy method\, and it is this wild method that helps us to extend some results to the asymmetric cases.
URL:https://cmsa.fas.harvard.edu/event/10-1-2021-member-seminar/
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211001T093000
DTEND;TZID=America/New_York:20211001T103000
DTSTAMP:20260511T141101
CREATED:20240304T101543Z
LAST-MODIFIED:20240304T101543Z
UID:10002898-1633080600-1633084200@cmsa.fas.harvard.edu
SUMMARY:Static vacuum extensions of Bartnik boundary data near flat domains
DESCRIPTION:Abstract: The study of static vacuum Riemannian metrics arises naturally in differential geometry and general relativity. It plays an important role in scalar curvature deformation\, as well as in constructing Einstein spacetimes.  Existence of static vacuum Riemannian metrics with prescribed Bartnik data is one of the most fundamental problems in Riemannian geometry related to general relativity. It is also a very interesting problem on the global solvability of a natural geometric boundary value problem. In this talk I will first discuss some basic properties of the nonlinear and linearized static vacuum equations and the geometric boundary conditions. Then I will present some recent progress towards the existence problem of static vacuum metrics based on a joint work with Lan-Hsuan Huang.
URL:https://cmsa.fas.harvard.edu/event/10-1-2021-general-relativity-seminar/
CATEGORIES:General Relativity Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211004T025100
DTEND;TZID=America/New_York:20211005T025100
DTSTAMP:20260511T141101
CREATED:20230705T081940Z
LAST-MODIFIED:20250328T200226Z
UID:10000071-1633315860-1633402260@cmsa.fas.harvard.edu
SUMMARY:Math Science Lectures in Honor of Raoul Bott
DESCRIPTION:On October 4th and October 5th\, 2021\, Harvard CMSA will host its annual Math Science Lectures in Honor of Raoul Bott. This year’s speaker will be Michael Freedman (Microsoft). The lectures will take place from 11:00am – 12:15pm (ET) on Zoom. \nThis will be the third annual lecture series held in honor of Raoul Bott. \n\n\n\n\nLecture 1\nOctober 4th\, 11:00am (Boston time)\nTitle: The Universe from a single Particle \nAbstract: I will explore a toy model  for our universe in which spontaneous symmetry breaking – acting on the level of operators (not states) – can produce the interacting physics we see about us from the simpler\, single particle\, quantum mechanics we study as undergraduates. Based on joint work with Modj Shokrian Zini\, see arXiv:2011.05917 and arXiv:2108.12709. \nVideo\n\n\nLecture 2\nOctober 5th\, 11:00am (Boston time)\nTitle: Controlled Mather Thurston Theorems. \nAbstract: The “c-principle” is a cousin of Gromov’s h-principle in which cobordism rather than homotopy is required to (canonically) solve a problem. We show that in certain well-known c-principle contexts only the mildest cobordisms\, semi-s-cobordisms\, are required. In physical applications\, the extra topology (a perfect fundamental group) these cobordisms introduce could easily be hidden in the UV. This leads to a proposal to recast gauge theories such as EM and the standard model in terms of flat connections rather than curvature. See arXiv:2006.00374   \nVideo\n\n\n\n 
URL:https://cmsa.fas.harvard.edu/event/math-science-lectures-in-honor-of-raoul-bott/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Public Lecture,Special Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211004T110000
DTEND;TZID=America/New_York:20211004T123000
DTSTAMP:20260511T141101
CREATED:20240212T110410Z
LAST-MODIFIED:20250409T192600Z
UID:10002032-1633345200-1633350600@cmsa.fas.harvard.edu
SUMMARY:Math Science Lectures in Honor of Raoul Bott: Michael Freedman
DESCRIPTION:On October 4th and October 5th\, 2021\, Harvard CMSA hosted the annual Math Science Lectures in Honor of Raoul Bott. This year’s speaker was Michael Freedman (Microsoft). The lectures took place on Zoom. \nThis will be the third annual lecture series held in honor of Raoul Bott. \n\n\n\n\nLecture 1\nOctober 4th\, 11:00am (Boston time)\nTitle: The Universe from a single Particle \nAbstract: I will explore a toy model  for our universe in which spontaneous symmetry breaking – acting on the level of operators (not states) – can produce the interacting physics we see about us from the simpler\, single particle\, quantum mechanics we study as undergraduates. Based on joint work with Modj Shokrian Zini\, see arXiv:2011.05917 and arXiv:2108.12709. \nVideo\n\n\nLecture 2\nOctober 5th\, 11:00am (Boston time)\nTitle: Controlled Mather Thurston Theorems. \nAbstract: The “c-principle” is a cousin of Gromov’s h-principle in which cobordism rather than homotopy is required to (canonically) solve a problem. We show that in certain well-known c-principle contexts only the mildest cobordisms\, semi-s-cobordisms\, are required. In physical applications\, the extra topology (a perfect fundamental group) these cobordisms introduce could easily be hidden in the UV. This leads to a proposal to recast gauge theories such as EM and the standard model in terms of flat connections rather than curvature. See arXiv:2006.00374   \nVideo\n\n\n\n 
URL:https://cmsa.fas.harvard.edu/event/math-science-lectures-in-honor-of-raoul-bott-3/
LOCATION:Virtual
CATEGORIES:Event,Math Science Lectures in Honor of Raoul Bott,Special Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211005T083000
DTEND;TZID=America/New_York:20211005T093000
DTSTAMP:20260511T141101
CREATED:20240213T111744Z
LAST-MODIFIED:20240304T104852Z
UID:10002487-1633422600-1633426200@cmsa.fas.harvard.edu
SUMMARY:Angular momentum in general relativity
DESCRIPTION:Abstract: The definition of angular momentum in general relativity has been a subtle issue since the 1960′\, due to the discovery of “supertranslation ambiguity”: the angular momentums recorded by two distant observers of the same system may not be the same. In this talk\, I shall show how the mathematical theory of optimal isometric embedding and quasilocal angular momentum identifies a correction term\, and leads to a new definition of angular momentum that is free of any supertranslation ambiguity. This is based on joint work with Po-Ning Chen\, Jordan Keller\, Ye-Kai Wang\, and Shing-Tung Yau.
URL:https://cmsa.fas.harvard.edu/event/10-5-2021-joint-harvard-cuhk-ymsc-differential-geometry-seminar/
CATEGORIES:Joint Harvard-CUHK-YMSC Differential Geometry
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211005T090000
DTEND;TZID=America/New_York:20211005T100000
DTSTAMP:20260511T141101
CREATED:20240213T113617Z
LAST-MODIFIED:20240304T085033Z
UID:10002508-1633424400-1633428000@cmsa.fas.harvard.edu
SUMMARY:10/5/2021 Combinatorics\, Physics and Probability Seminar
DESCRIPTION:Title: Geodesic Geometry on Graphs \nAbstract: In a graph G = (V\, E) we consider a system of paths S so that for every two vertices u\,v in V there is a unique uv path in S connecting them. The path system is said to be consistent if it is closed under taking subpaths\, i.e. if P is a path in S then any subpath of P is also in S. Every positive weight function w: E–>R^+ gives rise to a consistent path system in G by taking the paths in S to be geodesics w.r.t. w. In this case\, we say w induces S. We say a graph G is metrizable if every consistent path system in G is induced by some such w. \nWe’ll discuss the concept of graph metrizability\, and\, in particular\, we’ll see that while metrizability is a rare property\, there exists infinitely many 2-connected metrizable graphs. \nJoint work with Nati Linial.
URL:https://cmsa.fas.harvard.edu/event/10-5-2021-combinatorics-physics-and-probability-seminar/
CATEGORIES:Combinatorics Physics and Probability
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211006T093000
DTEND;TZID=America/New_York:20211006T103000
DTSTAMP:20260511T141101
CREATED:20240214T044013Z
LAST-MODIFIED:20240501T205719Z
UID:10002532-1633512600-1633516200@cmsa.fas.harvard.edu
SUMMARY:Strings\, knots and quivers
DESCRIPTION:Speaker: Piotr Sułkowski (University of Warsaw) \nTitle: Strings\, knots and quivers \nAbstract: I will discuss a recently discovered relation between quivers and knots\, as well as – more generally – toric Calabi-Yau manifolds. In the context of knots this relation is referred to as the knots-quivers correspondence\, and it states that various invariants of a given knot are captured by characteristics of a certain quiver\, which can be associated to this knot. Among others\, this correspondence enables to prove integrality of LMOV invariants of a knot by relating them to motivic Donaldson-Thomas invariants of the corresponding quiver\, it provides a new insight on knot categorification\, etc. This correspondence arises from string theory interpretation and engineering of knots in brane systems in the conifold geometry; replacing the conifold by other toric Calabi-Yau manifolds leads to analogous relations between such manifolds and quivers.
URL:https://cmsa.fas.harvard.edu/event/strings-knots-and-quivers/
LOCATION:Virtual
CATEGORIES:Colloquium
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211006T114900
DTEND;TZID=America/New_York:20211006T134900
DTSTAMP:20260511T141101
CREATED:20240214T090718Z
LAST-MODIFIED:20240301T093241Z
UID:10002606-1633520940-1633528140@cmsa.fas.harvard.edu
SUMMARY:Line defects in CFTs: Renormalization group flows and semiclassical limits
DESCRIPTION:Title: Line defects in CFTs: Renormalization group flows and semiclassical limits \nAbstract: I will discuss line defects in d-dimensional Conformal Field Theories (CFTs). In the first part of the talk\, I will argue that the ambient CFT places nontrivial constraints on Renormalization Group (RG) flows on such line defects. I will show that the flow on line defects is consequently irreversible and furthermore a canonical decreasing entropy function exists. This construction generalizes the g theorem to line defects in arbitrary dimensions.  In the second part of the talk\, I will present some applications. In particular\, I will discuss impurities with large isospin S for some O(3) symmetric theories in the epsilon expansion.  For sufficiently large S diagrammatic perturbation theory breaks down\, and these are studied in a semiclassical expansion at fixed epsilon S.
URL:https://cmsa.fas.harvard.edu/event/10-6-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211006T150000
DTEND;TZID=America/New_York:20211006T160000
DTSTAMP:20260511T141101
CREATED:20240214T092921Z
LAST-MODIFIED:20240517T200621Z
UID:10002630-1633532400-1633536000@cmsa.fas.harvard.edu
SUMMARY:New results in Supergravity via ML Technology
DESCRIPTION:Speaker: Thomas Fischbacher\, Google \nTitle: New results in Supergravity via ML Technology \nAbstract: The infrastructure built to power the Machine Learning revolution has many other uses beyond Deep Learning. Starting from a general architecture-level overview over the lower levels of Google’s TensorFlow machine learning library\, we review how this has recently helped us to find all the stable vacua of SO(8) Supergravity in 3+1 dimensions\, has allowed major progress on other related questions about M theory\, and briefly discuss other applications in field theory and beyond.
URL:https://cmsa.fas.harvard.edu/event/10-6-2021-new-technologies-in-mathematics-seminar/
CATEGORIES:New Technologies in Mathematics Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211007T115400
DTEND;TZID=America/New_York:20211007T135400
DTSTAMP:20260511T141102
CREATED:20240214T090253Z
LAST-MODIFIED:20240301T092837Z
UID:10002604-1633607640-1633614840@cmsa.fas.harvard.edu
SUMMARY:A tour of categorical symmetry
DESCRIPTION:Title: A tour of categorical symmetry \nAbstract: I will discuss some perspectives on symmetry coming from the study of topological defects in quantum field theory. I will argue that we should take topological defects themselves to define the symmetries of QFT. This gives us a view of the “category of QFTs”. I will describe some examples of these “categorical symmetries”\, their applications\, and some open problems.
URL:https://cmsa.fas.harvard.edu/event/10-7-2021-quantum-matter-in-mathematics-and-physics/
LOCATION:Virtual
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211007T130000
DTEND;TZID=America/New_York:20211007T140000
DTSTAMP:20260511T141102
CREATED:20240214T053935Z
LAST-MODIFIED:20240304T063527Z
UID:10002541-1633611600-1633615200@cmsa.fas.harvard.edu
SUMMARY:A mirror theorem for GLSMs
DESCRIPTION:Abstract: A gauged linear sigma model (GLSM) consists roughly of a complex vector space V\, a group G acting on V\, a character \theta of G\, and a G-invariant function w on V.  This data defines a GIT quotient Y = [V //_\theta G] and a function on that quotient.  GLSMs arise naturally in a number of contexts\, for instance as the mirrors to Fano manifolds and as examples of noncommutative crepant resolutions. GLSMs provide a broad setting in which it is possible to define an enumerative curve counting theory\, simultaneously generalizing FJRW theory and the Gromov-Witten theory of hypersurfaces. Despite a significant effort to rigorously define the enumerative invariants of a GLSM\, very few computations of these invariants have been carried out.  In this talk I will describe a new method for computing generating functions of GLSM invariants.  I will explain how these generating functions arise as derivatives of generating functions of Gromov-Witten invariants of Y.
URL:https://cmsa.fas.harvard.edu/event/a-mirror-theorem-for-glsms/
CATEGORIES:Algebraic Geometry in String Theory Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211007T184100
DTEND;TZID=America/New_York:20211007T184100
DTSTAMP:20260511T141102
CREATED:20240214T083403Z
LAST-MODIFIED:20240214T083403Z
UID:10002590-1633632060-1633632060@cmsa.fas.harvard.edu
SUMMARY:10/7/2021 Interdisciplinary Science Seminar
DESCRIPTION:Title: SiRNA Targeting TCRb: A Proposed Therapy for the Treatment of Autoimmunity \nAbstract: As of 2018\, the United States National Institutes of Health estimate that over half a billion people worldwide are affected by autoimmune disorders. Though these conditions are prevalent\, treatment options remain relatively poor\, relying primarily on various forms of immunosuppression which carry potentially severe side effects and often lose effectiveness over time. Given this\, new forms of therapy are needed. To this end\, we have developed methods for the creation of small-interfering RNA (siRNA) for hypervariable regions of the T-cell receptor β-chain gene (TCRb) as a highly targeted\, novel means of therapy for the treatment of autoimmune disorders. \nThis talk will review the general mechanism by which autoimmune diseases occur and discuss the pros and cons of conventional pharmaceutical therapies as they pertain to autoimmune disease treatment. I will then examine the rational and design methodology for the proposed siRNA therapy and how it contrasts with contemporary methods for the treatment of these conditions. Additionally\, the talk will compare the efficacy of multiple design strategies for such molecules by comparison over several metrics and discuss how this will be guiding future research.
URL:https://cmsa.fas.harvard.edu/event/10-7-2021-interdisciplinary-science-seminar/
CATEGORIES:Interdisciplinary Science Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211007T203000
DTEND;TZID=America/New_York:20211007T220000
DTSTAMP:20260511T141102
CREATED:20240301T093101Z
LAST-MODIFIED:20240301T093101Z
UID:10002891-1633638600-1633644000@cmsa.fas.harvard.edu
SUMMARY:UV/IR and Effective Field Theory
DESCRIPTION:Speaker: Nima Arkani-Hamed (IAS Princeton) \nTitle: UV/IR and Effective Field Theory
URL:https://cmsa.fas.harvard.edu/event/10-7-2021-quantum-matter-in-mathematics-and-physics-2/
CATEGORIES:Quantum Matter
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211008T093000
DTEND;TZID=America/New_York:20211008T103000
DTSTAMP:20260511T141102
CREATED:20240213T110012Z
LAST-MODIFIED:20240304T101810Z
UID:10002469-1633685400-1633689000@cmsa.fas.harvard.edu
SUMMARY:Causality Comparison and Postive Mass
DESCRIPTION:Speaker: Xiaoning Wu\, Chinese Academy of Sciences \nTitle: Causality Comparison and Postive Mass \nAbstract: Penrose et al. investigated the physical incoherence of the space-time with negative mass via the bending of light. Precise estimates of the time-delay of null geodesics were needed and played a pivotal role in their proof. In this paper\, we construct an intermediate diagonal metric and reduce this problem to a causality comparison in the compactified space-time regarding time-like connectedness near conformal infinities. This different approach allows us to avoid encountering the difficulties and subtle issues that Penrose et al. met. It provides a new\, substantially simple\, and physically natural non-partial differential equation viewpoint to understand the positive mass theorem. This elementary argument modestly applies to asymptotically flat solutions that are vacuum and stationary near infinity
URL:https://cmsa.fas.harvard.edu/event/10-8-2021-general-relativity-seminar/
CATEGORIES:General Relativity Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211008T093000
DTEND;TZID=America/New_York:20211008T103000
DTSTAMP:20260511T141102
CREATED:20240214T074201Z
LAST-MODIFIED:20240301T111834Z
UID:10002568-1633685400-1633689000@cmsa.fas.harvard.edu
SUMMARY:Knowledge Graph Embeddings and Inference
DESCRIPTION:Member Seminar \nSpeaker: Michael Douglas \nTitle: Knowledge Graph Embeddings and Inference \nAbstract: A knowledge graph (KG) is a data structure which represents entities and relations as the vertices and edges of a directed graph. Two examples are Wikidata for general knowledge and SemMedDB for biomedical data.\nA popular KG representation method is graph embedding\, which facilitates question answering\, inferring missing edges\, and logical reasoning tasks. In this talk we introduce the topic and explain relevant mathematical results on graph embedding. We then analyze KG inference into several mechanisms: motif learning\, network learning\, and unstructured statistical inference\, and describe experiments to measure the contributions of each mechanism. \nJoint work with M. Simkin\, O. Ben-Eliezer\, T. Wu\, S. P. Chin\, T. V. Dang and A. Wood.
URL:https://cmsa.fas.harvard.edu/event/10-8-2021-member-seminar/
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211012T090000
DTEND;TZID=America/New_York:20211012T100000
DTSTAMP:20260511T141102
CREATED:20240213T114547Z
LAST-MODIFIED:20240304T100222Z
UID:10002513-1634029200-1634032800@cmsa.fas.harvard.edu
SUMMARY:10/12/2021 Combinatorics\, Physics and Probability Seminar
DESCRIPTION:Title: On counting algebraically defined graphs \nAbstract: For many classes of graphs that arise naturally in discrete geometry (for example intersection graphs of segments or disks in the plane)\, the edges of these graphs can be defined algebraically using the signs of a finite list of fixed polynomials. We investigate the number of n-vertex graphs in such an algebraically defined class of graphs. Warren’s theorem (a variant of a theorem of Milnor and Thom) implies upper bounds for the number of n-vertex graphs in such graph classes\, but all the previously known lower bounds were obtained from ad hoc constructions for very specific classes. We prove a general theorem giving a lower bound for this number (under some reasonable assumptions on the fixed list of polynomials)\, and this lower bound essentially matches the upper bound from Warren’s theorem.
URL:https://cmsa.fas.harvard.edu/event/10-12-2021-combinatorics-physics-and-probability-seminar/
CATEGORIES:Combinatorics Physics and Probability
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211012T130000
DTEND;TZID=America/New_York:20211012T140000
DTSTAMP:20260511T141102
CREATED:20240214T053342Z
LAST-MODIFIED:20240304T063443Z
UID:10002540-1634043600-1634047200@cmsa.fas.harvard.edu
SUMMARY:Derived projectivizations of two-term complexes
DESCRIPTION:Abstract: For a given two-term complex of vector bundles on a derived scheme (or stack)\, there are three natural ways to define its “derived projectivizations”: (i) as the derived base-change of the classical projectivization of Grothendieck; (ii) as the derived moduli parametrizing one-dimensional locally free quotients; (iii) as the GIT quotient of the total space by $\mathbb{G}_m$-action. In this talk\, we first show that these three definitions are equivalent. Second\, we prove a structural theorem about the derived categories of derived projectivizations and study the corresponding mutation theory. Third\, we apply these results to various moduli situations\, including the moduli of certain stable pairs on curves and the Hecke correspondences of one-point modification of moduli of stable sheaves on surfaces. If time allowed\, we could also discuss the generalizations of these results to the derived Quot schemes of locally free quotients.
URL:https://cmsa.fas.harvard.edu/event/derived-projectivizations-of-two-term-complexes/
CATEGORIES:Algebraic Geometry in String Theory Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211013T030000
DTEND;TZID=America/New_York:20211013T040000
DTSTAMP:20260511T141102
CREATED:20240213T113713Z
LAST-MODIFIED:20240304T100928Z
UID:10002509-1634094000-1634097600@cmsa.fas.harvard.edu
SUMMARY:Some remarks on contact Calabi-Yau 7-manifolds
DESCRIPTION:Abstract: In geometry and physics it has proved useful to relate G2 and Calabi-Yau geometry via circle bundles. Contact Calabi-Yau 7-manifolds are\, in the simplest cases\, such circle bundles over Calabi-Yau 3-orbifolds. These 7-manifolds provide testing grounds for the study of geometric flows which seek to find torsion-free G2-structures (and thus Ricci flat metrics with exceptional holonomy). They also give useful backgrounds to examine the heterotic G2 system (also known as the G2-Hull-Strominger system)\, which is a coupled set of PDEs arising from physics that involves the G2-structure and gauge theory on the 7-manifold. I will report on recent progress on both of these directions in the study of contact Calabi-Yau 7-manifolds\, which is joint work with H. Sá Earp and J. Saavedra.
URL:https://cmsa.fas.harvard.edu/event/10-13-2021-joint-harvard-cuhk-ymsc-differential-geometry-seminar/
CATEGORIES:Joint Harvard-CUHK-YMSC Differential Geometry
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211013T093000
DTEND;TZID=America/New_York:20211013T103000
DTSTAMP:20260511T141102
CREATED:20240214T043728Z
LAST-MODIFIED:20240507T193448Z
UID:10002531-1634117400-1634121000@cmsa.fas.harvard.edu
SUMMARY:Knot homology and sheaves on the Hilbert scheme of points on the plane
DESCRIPTION:Speaker: Alexei Oblomkov (University of Massachusetts) \nTitle: Knot homology and sheaves on the Hilbert scheme of points on the plane \nAbstract: The knot homology (defined by Khovavov\, Rozansky) provide us with a refinement of the knot polynomial knot invariant defined by Jones. However\, the knot homology are much harder to compute compared to the polynomial invariant of Jones. In my talk I present recent developments that allow us to use tools of algebraic geometry to compute the homology of torus knots and prove long-standing conjecture on the Poincare duality the knot homology. In more details\, using physics ideas of Kapustin-Rozansky-Saulina\, in the joint work with Rozansky\, we provide a mathematical construction that associates to a braid on n strands a complex of sheaves on the Hilbert scheme of n points on the plane. The knot homology of the closure of the braid is a space of sections of this sheaf. The sheaf is also invariant with respect to the natural symmetry of the plane\, the symmetry is the geometric counter-part of the mentioned Poincare duality.
URL:https://cmsa.fas.harvard.edu/event/knot-homology-and-sheaves-on-the-hilbert-scheme-of-points-on-the-plane/
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.13.21-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211013T140000
DTEND;TZID=America/New_York:20211013T150000
DTSTAMP:20260511T141102
CREATED:20240214T093531Z
LAST-MODIFIED:20240515T204354Z
UID:10002637-1634133600-1634137200@cmsa.fas.harvard.edu
SUMMARY:Computer-Aided Mathematics and Satisfiability
DESCRIPTION:Speaker: Marijn Heule\, Carnegie Mellon University \nTitle: Computer-Aided Mathematics and Satisfiability \nAbstract: Progress in satisfiability (SAT) solving has made it possible to determine the correctness of complex systems and answer long-standing open questions in mathematics. The SAT solving approach is completely automatic and can produce clever though potentially gigantic proofs. We can have confidence in the correctness of the answers because highly trustworthy systems can validate the underlying proofs regardless of their size. We demonstrate the effectiveness of the SAT approach by presenting some recent successes\, including the solution of the Boolean Pythagorean Triples problem\, computing the fifth Schur number\, and resolving the remaining case of Keller’s conjecture. Moreover\, we constructed and validated a proof for each of these results. The second part of the talk focuses on notorious math challenges for which automated reasoning may well be suitable. In particular\, we discuss our progress on applying SAT solving techniques to the chromatic number of the plane (Hadwiger-Nelson problem)\, optimal schemes for matrix multiplication\, and the Collatz conjecture.
URL:https://cmsa.fas.harvard.edu/event/10-13-2021-new-technologies-in-mathematics-seminar/
CATEGORIES:New Technologies in Mathematics Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211014T090000
DTEND;TZID=America/New_York:20211014T100000
DTSTAMP:20260511T141102
CREATED:20240214T082843Z
LAST-MODIFIED:20240529T180858Z
UID:10002588-1634202000-1634205600@cmsa.fas.harvard.edu
SUMMARY:D3C: Reducing the Price of Anarchy in Multi-Agent Learning
DESCRIPTION:Speaker: Ian Gemp\, DeepMind \nTitle: D3C: Reducing the Price of Anarchy in Multi-Agent Learning \nAbstract: In multi-agent systems the complex interaction of fixed incentives can lead agents to outcomes that are poor (inefficient) not only for the group but also for each individual agent. Price of anarchy is a technical game theoretic definition introduced to quantify the inefficiency arising in these scenarios– it compares the welfare that can be achieved through perfect coordination against that achieved by self-interested agents at a Nash equilibrium. We derive a differentiable upper bound on a price of anarchy that agents can cheaply estimate during learning. Equipped with this estimator agents can adjust their incentives in a way that improves the efficiency incurred at a Nash equilibrium. Agents adjust their incentives by learning to mix their reward (equiv. negative loss) with that of other agents by following the gradient of our derived upper bound. We refer to this approach as D3C. In the case where agent incentives are differentiable D3C resembles the celebrated Win-Stay Lose-Shift strategy from behavioral game theory thereby establishing a connection between the global goal of maximum welfare and an established agent-centric learning rule. In the non-differentiable setting as is common in multiagent reinforcement learning we show the upper bound can be reduced via evolutionary strategies until a compromise is reached in a distributed fashion. We demonstrate that D3C improves outcomes for each agent and the group as a whole on several social dilemmas including a traffic network exhibiting Braess’s paradox a prisoner’s dilemma and several reinforcement learning domains.
URL:https://cmsa.fas.harvard.edu/event/10-14-2021-interdisciplinary-science-seminar/
LOCATION:Virtual
CATEGORIES:Interdisciplinary Science Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Interdisciplinary-Science-Seminar-10.14.21.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211014T130000
DTEND;TZID=America/New_York:20211014T143000
DTSTAMP:20260511T141102
CREATED:20240213T113426Z
LAST-MODIFIED:20240304T084942Z
UID:10002506-1634216400-1634221800@cmsa.fas.harvard.edu
SUMMARY:Stochastic PDE as scaling limits of interacting particle systems
DESCRIPTION:Abstract: Interacting particle models are often employed to gain understanding of the emergence of macroscopic phenomena from microscopic laws of nature. These individual-based models capture fine details\, including randomness and discreteness of individuals\, that are not considered in continuum models such as partial differential equations (PDE) and integral-differential equations. The challenge is how to simultaneously retain key information in microscopic models as well as efficiency and robustness of macroscopic models. In this talk\, I will illustrate how this challenge can be overcome by elucidating the probabilistic connections between models of different levels of detail. These connections explain how stochastic partial differential equations (SPDE) arise naturally from particle models. \nI will also present some novel scaling limits including SPDE on graphs and coupled SPDE. These SPDE not only interpolate between particle models and PDE\, but also quantify the source and the order of magnitude of stochasticity. Scaling limit theorems and duality formulas are obtained for these SPDE\, which connect phenomena across scales and offer insights about the genealogies and the time-asymptotic properties of the underlying population dynamics.
URL:https://cmsa.fas.harvard.edu/event/stochastic-pde-as-scaling-limits-of-interacting-particle-systems/
CATEGORIES:Active Matter Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211015T093000
DTEND;TZID=America/New_York:20211015T103000
DTSTAMP:20260511T141102
CREATED:20240213T105113Z
LAST-MODIFIED:20240304T101004Z
UID:10002463-1634290200-1634293800@cmsa.fas.harvard.edu
SUMMARY:Peeling properties of the spinor fields and the solutions to nonlinear Dirac equations
DESCRIPTION:Abstract: The Dirac equation is a relativistic equation that describes the spin-1/2 particles.  We talk about Dirac equations in Minkowski spacetime. In a geometric viewpoint\, we can see that the spinor fields satisfying the Dirac equations enjoy the so-called peeling properties. It means the null components of the solution will decay at different rates along the null hypersurface. Based on this decay mechanism\, we can obtain a fresh insight to the spinor null forms which is used to prove a small data global existence result especially for some quadratic Dirac models.
URL:https://cmsa.fas.harvard.edu/event/10-15-2021-general-relativity-seminar/
CATEGORIES:General Relativity Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20211015T093000
DTEND;TZID=America/New_York:20211015T103000
DTSTAMP:20260511T141102
CREATED:20240214T073928Z
LAST-MODIFIED:20240301T111732Z
UID:10002566-1634290200-1634293800@cmsa.fas.harvard.edu
SUMMARY:C-P-T Fractionalization\, and Quantum Criticality Beyond the Standard Model
DESCRIPTION:Member Seminar \nSpeaker: Juven Wang \nTitle: C-P-T Fractionalization\, and Quantum Criticality Beyond the Standard Model \nAbstract: Discrete spacetime symmetries of parity P or reflection R\, and time-reversal T\, act naively as a Z2-involution on the spacetime coordinates; but together with a charge conjugation C and the fermion parity (−1)^F\, these symmetries can be further fractionalized forming nonabelian C-P-R-T-(−1)^F group structures\, in various examples such as relativistic Lorentz invariant Dirac spinor quantum field theories (QFT)\, or nonrelativistic quantum many-body systems (involving Majorana zero modes). This result answers Prof. Shing-Tung Yau’s question on “Can C-P-T symmetries be fractionalized more than involutions?” based on arxiv:2109.15320. \nIn the second part of my talk\, I will sketch to explain how can we modify the so(10) Grand Unified Theory (GUT) by adding a new topological term such that two GUTs of Georgi-Glashow and Pati-Salam can smoother into each other in a quantum phase transition\, where the Standard Model and new dark sector physics can occur naturally near the critical region. The new modified so(10) GUT requires a double Spin structure that we name DSpin. This phenomenon is inspired by the “deconfined quantum criticality” in condensed matter. Based on arxiv:2106.16248.
URL:https://cmsa.fas.harvard.edu/event/10-15-2021-member-seminar/
CATEGORIES:Member Seminar
END:VEVENT
END:VCALENDAR