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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240513T163000
DTEND;TZID=America/New_York:20240513T173000
DTSTAMP:20240508T203329Z
CREATED:20240130T151206Z
LAST-MODIFIED:20240508T203329Z
UID:10000814-1715617800-1715621400@live-hu-cmsa-222.pantheonsite.io
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://live-hu-cmsa-222.pantheonsite.io/event/colloquium-4124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Colloquium-05.13.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240513T133000
DTEND;TZID=America/New_York:20240513T143000
DTSTAMP:20240509T162010Z
CREATED:20240509T150634Z
LAST-MODIFIED:20240509T162010Z
UID:10003386-1715607000-1715610600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Improving Mean-Field Theory for Quantum Magnets
DESCRIPTION:Quantum Matter in Mathematics and Physics Seminar \nSpeaker: Junyi Zhang\, Johns Hopkins University \nTitle: Improving Mean-Field Theory for Quantum Magnets \nAbstract: Frustrated magnets have garnered significant attention because of their potential to host exotic spin liquids\, while many real material candidates exhibit magnetic orders.  Due to their proximity to spin liquid phases\, the semiclassical descriptions of these magnetic orders often fall short in capturing their intricate quantum behaviors. In this talk\, I will introduce an improved mean-field method\, named density-matrix mean-field theory (DMMFT)\, for these quantum magnets. Using local reduced density matrix\, DMMFT can systematically incorporate the quantum fluctuations beyond conventional mean-field theories. Notably\, it not only quantitatively evaluates the renormalization of order parameters induced by quantum fluctuations but also has the capability to detect the topological order of quantum phases. DMMFT offers an efficient approach to explore phases displaying unconventional quantum orders\, particularly beneficial for investigating frustrated spin systems in high spatial dimensions. \nRef: https://arxiv.org/abs/2401.06236
URL:https://live-hu-cmsa-222.pantheonsite.io/event/qm_51324/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-QMMP-05.13.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240513T110000
DTEND;TZID=America/New_York:20240513T120000
DTSTAMP:20240514T142424Z
CREATED:20240411T181646Z
LAST-MODIFIED:20240514T142424Z
UID:10003354-1715598000-1715601600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:An analogue of non-interacting quantum field theory in Riemannian signature
DESCRIPTION:General Relativity Seminar \nSpeaker: Mikhail Molodyk\, Stanford \nTitle: An analogue of non-interacting quantum field theory in Riemannian signature \nAbstract: Recent advances using microlocal tools have led to constructions\, for wave operators on various classes of spacetimes\, of four distinguished Fredholm inverses which have the singular behavior required of retarded\, advanced\, Feynman\, and anti-Feynman propagators in QFT. Vasy and Wrochna have used these to define a QFT on asymptotically Minkowski spacetimes\, for which they construct Hadamard states described by asymptotic data at infinity. I will describe an analogue of this construction on Riemannian manifolds with two asymptotically conic ends\, defining quantum fields satisfying the Helmholtz equation and using scattering data to construct states satisfying a wavefront mapping-property version of the Hadamard condition. The absence of a spacetime interpretation lends itself to a sharper focus on the theory’s analytic structure\, from whose perspective the Feynman propagators are no less natural than the advanced/retarded ones. I will also highlight some differences between Feynman propagators defined as distinguished inverses and as time-ordered expectations. Based on joint work with András Vasy.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/general-relativity-51324/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:General Relativity Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-GR-Seminar-05.13.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240510T120000
DTEND;TZID=America/New_York:20240510T130000
DTSTAMP:20240507T190133Z
CREATED:20240416T185907Z
LAST-MODIFIED:20240507T190133Z
UID:10000695-1715342400-1715346000@live-hu-cmsa-222.pantheonsite.io
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://live-hu-cmsa-222.pantheonsite.io/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://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Member-Seminar-05.10.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240510T100000
DTEND;TZID=America/New_York:20240510T113000
DTSTAMP:20240508T195139Z
CREATED:20240507T190917Z
LAST-MODIFIED:20240508T195139Z
UID:10001518-1715335200-1715340600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:From quantum Hall to Hubbard physics in twisted bilayer graphene
DESCRIPTION:Quantum Matter in Mathematics and Physics Seminar \nSpeaker: Eslam Khalaf (Harvard) \nTitle: From quantum Hall to Hubbard physics in twisted bilayer graphene \n\nAbstract: Early on it was noticed that twisted bilayer graphene (TBG) has elements in common with two paradigmatic examples of strongly correlated physics: Hubbard physics and quantum Hall physics. On the one hand\, TBG hosts flat topological Landau-level-like bands which realize quantum anomalous Hall states and orbital ferromagnetism under the right conditions. On the other hand\, these bands are characterized by concentrated charge density and show experimental signs of fluctuating magnetism\, and unconventional superconductivty; all characteristics of Hubbard-model-like physics. The emergence of fluctuating moments is particularly surprising\, as localized Wannier states do not exist in topological bands. I will discuss a phenomenological model for the flat bands in TBG that centers the concentration of charge density and\, relatedly\, the concentration of Berry flux. The bands obtained have excellent quantitative agreement with the Bistritzer-Macdonald model for realistic parameters. I will show that\, rather remarkably\, the model hosts decoupled flavor moments which despite being only power-law delocalized with infinite localization length\, have parametrically small overlap with each other. I will show how this unifies many of the observations in TBG and leads to a novel Mott semimetal phase for intermediate temperatures where moments are thermally disordered but charge fluctuations are mostly frozen.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/qm_51024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-QMMP-05.10.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240509T103000
DTEND;TZID=America/New_York:20240509T113000
DTSTAMP:20240507T152049Z
CREATED:20240416T133629Z
LAST-MODIFIED:20240507T152049Z
UID:10000890-1715250600-1715254200@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Computing periods of hypersurfaces and elliptic surfaces via effective homology
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Eric Pichon-Pharabod\, Universite Paris-Saclay \nTitle: Computing periods of hypersurfaces and elliptic surfaces via effective homology \nAbstract: The period matrix of a smooth complex projective variety X encodes the isomorphism between its singular homology and its algebraic De Rham cohomology. Numerical approximations with sufficient precision of the entries of this matrix\, called periods\, allow to recover some algebraic invariants of the variety\, such as the Néron-Severi group in the case of surfaces. In this talk\, we will present a method relying on the computation of an effective description of the homology for obtaining such numerical approximations of the periods of hypersurfaces and elliptic surfaces.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/agst-5924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/Algebraic-Geometry-in-String-Theory-05.09.2024.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240508T150000
DTEND;TZID=America/New_York:20240508T160000
DTSTAMP:20240429T182143Z
CREATED:20240415T180235Z
LAST-MODIFIED:20240429T182143Z
UID:10003368-1715180400-1715184000@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Ruth Britto\, Trinity \nTitle: Cuts and Symbols
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_5824/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240507T150000
DTEND;TZID=America/New_York:20240507T160000
DTSTAMP:20240417T200650Z
CREATED:20240415T175924Z
LAST-MODIFIED:20240417T200650Z
UID:10003367-1715094000-1715097600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Jacob Bourjaily\, Penn State \nTitle: The Algebraic and Transcendental Structure of Perturbative QFT
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_5724/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240507T120000
DTEND;TZID=America/New_York:20240507T130000
DTSTAMP:20240813T155522Z
CREATED:20240207T190343Z
LAST-MODIFIED:20240813T155522Z
UID:10000693-1715083200-1715086800@live-hu-cmsa-222.pantheonsite.io
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://live-hu-cmsa-222.pantheonsite.io/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://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Member-Seminar-05.07.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240506T163000
DTEND;TZID=America/New_York:20240506T173000
DTSTAMP:20240507T201738Z
CREATED:20240319T201629Z
LAST-MODIFIED:20240507T201738Z
UID:10000819-1715013000-1715016600@live-hu-cmsa-222.pantheonsite.io
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://live-hu-cmsa-222.pantheonsite.io/event/colloquium-5624/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Colloquium-05.06.2024.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240503T110000
DTEND;TZID=America/New_York:20240503T120000
DTSTAMP:20240501T155445Z
CREATED:20240430T205406Z
LAST-MODIFIED:20240501T155445Z
UID:10003385-1714734000-1714737600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Andrew McLeod\, Edinburgh \nTitle: Genealogical Constraints on Feynman Integrals
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_5324/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240502T163000
DTEND;TZID=America/New_York:20240502T172000
DTSTAMP:20240422T153733Z
CREATED:20240415T163546Z
LAST-MODIFIED:20240422T153733Z
UID:10003358-1714667400-1714670400@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Symmetry Colloquia  - Global Categorical Symmetries
DESCRIPTION:Symmetry Colloquia – Global Categorical Symmetries \nMay 2\, 2024 \nLocation: Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nSpeaker: Theo Johnson-Freyd\, Dalhousie University and Perimeter Institute \nTitle: The Universal Target Category \nAbstract: Hilbert’s Nullstellensatz says that the complex numbers C satisfy a universal property among all R-algebras: every not-too-large nonzero commutative R-algebra maps to C. Deligne proved a similar statement in categorical dimension 1: every not-too-large symmetric monoidal category over R maps to the category sVec of super vector spaces. In other words\, sVec (and not Vec!) is “algebraically closed”. These statements help explain why quantum field theory requires imaginary numbers and fermions. I will describe the universal symmetric monoidal higher category that extends the sequence C\, sVec\, …. This is joint work in progress with David Reutter\, and builds on closely-related work by GCS collaborators Freed\, Scheimbauer\, and Teleman and Schlank et al.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/gcs24_johnson-freyd/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Symmetry Colloquia
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/Pages-from-2105.15167_Johnson-Freyd.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240502T150000
DTEND;TZID=America/New_York:20240502T155000
DTSTAMP:20240417T181737Z
CREATED:20240415T163531Z
LAST-MODIFIED:20240417T181737Z
UID:10003357-1714662000-1714665000@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Symmetry Colloquia  - Global Categorical Symmetries
DESCRIPTION:Symmetry Colloquia – Global Categorical Symmetries \nMay 2\, 2024 \nLocation: Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nSpeaker: Thomas Dumitrescu\, UCLA \nTitle: Symmetries\, Invertible Field Theories\, and Gauge Theory Phases \nAbstract: I will start with a brief overview of gauge theory phases in 3+1 dimensions through the lens of higher symmetries — in particular the realization of 1-form symmetries acting on loop order parameters. I will then review recent progress in refining this characterization using invertible field theories\, or equivalently symmetry protected topological phases (SPTs). This refinement leads to new results in gauge theories with fundamental matter\, such as quantum chromodynamics (QCD)\, which do not possess 1-form symmetries. I will explain why these theories must sometimes undergo a phase transition between their confining and Higgs regimes\, despite the fact that classic results and standard lore say they should be continuously connected.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/gcs24_dumitrescu/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Symmetry Colloquia
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/Pages-from-2312.16898_phase-transition.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240502T140000
DTEND;TZID=America/New_York:20240502T145000
DTSTAMP:20240417T181513Z
CREATED:20240415T162849Z
LAST-MODIFIED:20240417T181513Z
UID:10003356-1714658400-1714661400@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Symmetry Colloquia - Global Categorical Symmetries
DESCRIPTION:Symmetry Colloquia – Global Categorical Symmetries \nMay 2\, 2024 \nLocation: Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nSpeaker: Clay Còrdova\, University of Chicago \nTitle:  Particle-Soliton Degeneracies from Spontaneously Broken Non-Invertible Symmetry \nAbstract: We study non-invertible topological symmetry operators in massive quantum field theories in (1+1) dimensions. In phases where this symmetry is spontaneously broken we show that the particle spectrum often has degeneracies dictated by the non-invertible symmetry and we deduce a procedure to determine the allowed multiplets. These degeneracies are robust predictions and do not require integrability or other special features of renormalization group flows. We exhibit these conclusions in examples where the spectrum is known\, recovering soliton and particle degeneracies. For instance\, the Tricritical Ising model deformed by the subleading Z2 odd operator flows to a gapped phase with two degenerate vacua. This flow enjoys a Fibonacci fusion category symmetry which implies a threefold degeneracy of its particle states\, relating the mass of solitons interpolating between vacua and particles supported in a single vacuum.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/gcs24_cordova/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Event,Symmetry Colloquia
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/Pages-from-2403.08883_2.47.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240501T170000
DTEND;TZID=America/New_York:20240501T180000
DTSTAMP:20240423T135511Z
CREATED:20240423T135511Z
LAST-MODIFIED:20240423T135511Z
UID:10003380-1714582800-1714586400@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Stephan Stieberger\, Max Planck Institute \nTitle: One-loop Double Copy Relation in String Theory and Twisted (Co)homology
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_51243/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240501T160000
DTEND;TZID=America/New_York:20240501T170000
DTSTAMP:20240422T142214Z
CREATED:20240415T182314Z
LAST-MODIFIED:20240422T142214Z
UID:10003370-1714579200-1714582800@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Livia Ferro\, University of Hertfordshire \nTitle: Scattering Amplitudes from Null-cone Geometry
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_51242/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240501T150000
DTEND;TZID=America/New_York:20240501T160000
DTSTAMP:20240429T134856Z
CREATED:20240415T175837Z
LAST-MODIFIED:20240429T134856Z
UID:10003366-1714575600-1714579200@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Yu-tin Huang\, National Taiwan University \nTitle: Loop in trees: Chambers in amplitudes and correlation functions
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_5124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240429T163000
DTEND;TZID=America/New_York:20240429T173000
DTSTAMP:20240424T142108Z
CREATED:20240207T190153Z
LAST-MODIFIED:20240424T142108Z
UID:10000818-1714408200-1714411800@live-hu-cmsa-222.pantheonsite.io
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://live-hu-cmsa-222.pantheonsite.io/event/colloquium-42924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Colloquium-04.29.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240429T090000
DTEND;TZID=America/New_York:20240503T170000
DTSTAMP:20240624T182013Z
CREATED:20240105T071054Z
LAST-MODIFIED:20240624T182013Z
UID:10001119-1714381200-1714755600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Workshop on Global Categorical Symmetries
DESCRIPTION:The CMSA will be hosting a Workshop on Global Categorical Symmetries from April 29–May 3\, 2024. \nParticipation in the workshop is by invitation. \nThe workshop will hold three Symmetry Colloquia open to the community on Thursday\, May 2\, 2024. \nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nTime: 2:00 – 2:50 pm \nSpeaker: Clay Còrdova\, University of Chicago \nTitle: Particle-Soliton Degeneracies from Spontaneously Broken Non-Invertible Symmetry \nAbstract: We study non-invertible topological symmetry operators in massive quantum field theories in (1+1) dimensions. In phases where this symmetry is spontaneously broken we show that the particle spectrum often has degeneracies dictated by the non-invertible symmetry and we deduce a procedure to determine the allowed multiplets. These degeneracies are robust predictions and do not require integrability or other special features of renormalization group flows. We exhibit these conclusions in examples where the spectrum is known\, recovering soliton and particle degeneracies. For instance\, the Tricritical Ising model deformed by the subleading Z2 odd operator flows to a gapped phase with two degenerate vacua. This flow enjoys a Fibonacci fusion category symmetry which implies a threefold degeneracy of its particle states\, relating the mass of solitons interpolating between vacua and particles supported in a single vacuum. \n  \nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nTime: 3:00 – 3:50 pm \nSpeaker: Thomas Dumitrescu\, UCLA \nTitle: Symmetries\, Invertible Field Theories\, and Gauge Theory Phases \nAbstract: I will start with a brief overview of gauge theory phases in 3+1 dimensions through the lens of higher symmetries — in particular the realization of 1-form symmetries acting on loop order parameters. I will then review recent progress in refining this characterization using invertible field theories\, or equivalently symmetry protected topological phases (SPTs). This refinement leads to new results in gauge theories with fundamental matter\, such as quantum chromodynamics (QCD)\, which do not possess 1-form symmetries. I will explain why these theories must sometimes undergo a phase transition between their confining and Higgs regimes\, despite the fact that classic results and standard lore say they should be continuously connected. \n  \nLocation:  Room G-10\, CMSA\, 20 Garden Street\, Cambridge MA 02138 \nTime: 4:30 – 5:20 pm \nSpeaker: Theo Johnson-Freyd\, Dalhousie University and Perimeter Institute \nTitle: The Universal Target Category \nAbstract: Hilbert’s Nullstellensatz says that the complex numbers C satisfy a universal property among all R-algebras: every not-too-large nonzero commutative R-algebra maps to C. Deligne proved a similar statement in categorical dimension 1: every not-too-large symmetric monoidal category over R maps to the category sVec of super vector spaces. In other words\, sVec (and not Vec!) is “algebraically closed”. These statements help explain why quantum field theory requires imaginary numbers and fermions. I will describe the universal symmetric monoidal higher category that extends the sequence C\, sVec\, …. This is joint work in progress with David Reutter\, and builds on closely-related work by GCS collaborators Freed\, Scheimbauer\, and Teleman and Schlank et al. \n  \nOrganizers:\nDan Freed (Harvard CMSA & Math)\nConstantin Teleman  (UC Berkeley) \nThis event is co-sponsored by the Simons Foundation. 
URL:https://live-hu-cmsa-222.pantheonsite.io/event/globalcomputing24/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Workshop
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/Symmetry-Lectures-poster-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240426T120000
DTEND;TZID=America/New_York:20240426T130000
DTSTAMP:20240416T185829Z
CREATED:20240305T160053Z
LAST-MODIFIED:20240416T185829Z
UID:10000691-1714132800-1714136400@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Member Seminar
DESCRIPTION:CMSA Member Seminar \nSpeaker: Matteo Parisi\, Harvard CMSA
URL:https://live-hu-cmsa-222.pantheonsite.io/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:20240426T103000
DTEND;TZID=America/New_York:20240426T120000
DTSTAMP:20240418T195101Z
CREATED:20240416T135637Z
LAST-MODIFIED:20240418T195101Z
UID:10001516-1714127400-1714132800@live-hu-cmsa-222.pantheonsite.io
SUMMARY:What Observables are Safe to Calculate?
DESCRIPTION:Quantum Matter in Mathematics and Physics Seminar \nSpeaker: Jesse Thaler\, MIT \nTitle: What Observables are Safe to Calculate? \nAbstract: In collider physics\, perturbative quantum field theory is the workhorse framework for computing theoretical predictions to compare to experimental measurements. An observable is called “safe” if its cross section can be predicted order-by-order in perturbation theory with controlled non-perturbative corrections. In this talk\, I show that naive definitions of “safety” are inadequate to determine which observable are perturbatively calculable. I then argue for a more refined definition of safety based on principles from optimal transport theory.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/qm_42624_2/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-QMMP-04.26.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240425T161500
DTEND;TZID=America/New_York:20240425T171500
DTSTAMP:20240415T174731Z
CREATED:20240415T174444Z
LAST-MODIFIED:20240415T174731Z
UID:10003363-1714061700-1714065300@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Tomasz Taylor\, Northeastern University \nTitle: Progress in Yang-Mills-Liouville Theory
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_42524/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240419T120000
DTEND;TZID=America/New_York:20240419T130000
DTSTAMP:20240418T194607Z
CREATED:20240305T155850Z
LAST-MODIFIED:20240418T194607Z
UID:10000689-1713528000-1713531600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Member Seminar
DESCRIPTION:CMSA Member Seminar \nSpeaker: Sunghyuk Park\, Harvard CMSA \nTitle: 3D quantum trace map \nAbstract: I will speak about my recent work (joint with Sam Panitch) constructing the 3d quantum trace map\, a homomorphism from the Kauffman bracket skein module of an ideally triangulated 3-manifold to its (square root) quantum gluing module\, thereby giving a precise relationship between the two quantizations of the character variety of ideally triangulated 3-manifolds. Our construction is based on the study of stated skein modules and their behavior under splitting\, especially into face suspensions. \n 
URL:https://live-hu-cmsa-222.pantheonsite.io/event/member-seminar-41924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Member-Seminar-04.19.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240419T100000
DTEND;TZID=America/New_York:20240419T113000
DTSTAMP:20240412T153042Z
CREATED:20240319T134714Z
LAST-MODIFIED:20240412T153042Z
UID:10001515-1713520800-1713526200@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Fusion Rule Measurement in a Topological Qubit
DESCRIPTION:Quantum Matter in Mathematics and Physics Seminar \nSpeaker: Chetan Nayak\, Microsoft and UCSB \nTitle: Fusion Rule Measurement in a Topological Qubit
URL:https://live-hu-cmsa-222.pantheonsite.io/event/qm-41924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-QMMP-04.19.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240418T101500
DTEND;TZID=America/New_York:20240418T113000
DTSTAMP:20240813T153315Z
CREATED:20240415T133328Z
LAST-MODIFIED:20240813T153315Z
UID:10000887-1713435300-1713439800@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Geometric local systems on very general curves
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Aaron Landesman\, MIT \nTitle: Geometric local systems on very general curves \nAbstract: What is the smallest genus h of a non-isotrivial curve over the generic genus g curve? In joint work with Daniel Litt\, we show h is more than $\sqrt{g}$ by proving amore general result about variations of Hodge structure on sufficiently general curves. As a consequence\, we show that local systems on a sufficiently general curve of geometric origin are not Zariski dense in the character variety parameterizing such local systems. This gives counterexamples to conjectures of Esnault-Kerz and Budur-Wang.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/agst-41824/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/Algebraic-Geometry-in-String-Theory-04.18.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240416T161500
DTEND;TZID=America/New_York:20240416T171500
DTSTAMP:20240415T174657Z
CREATED:20240415T173854Z
LAST-MODIFIED:20240415T174657Z
UID:10003362-1713284100-1713287700@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mathematical Aspects of Scattering Amplitudes Lecture
DESCRIPTION:Mathematical Aspects of Scattering Amplitudes Lecture \nSpeaker: Sabrina Pasterski\, Perimeter Institute \nTitle: Radiation in Holography
URL:https://live-hu-cmsa-222.pantheonsite.io/event/scatteringamplitudes_41624/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Scattering Amplitudes Lectures
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240412T120000
DTEND;TZID=America/New_York:20240412T130000
DTSTAMP:20240410T234826Z
CREATED:20240305T155803Z
LAST-MODIFIED:20240410T234826Z
UID:10000687-1712923200-1712926800@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Global weak solutions of 3+1 dimensional vacuum Einstein equations 
DESCRIPTION:CMSA Member Seminar \nSpeaker: Puskar Mondal \nTitle: Global weak solutions of 3+1 dimensional vacuum Einstein equations \nAbstract: It is important to understand if the `solutions’ of non-linear evolutionary PDEs persist for all time or become extinct in finite time through the blow-up of invariant entities. Now the question of this global existence or finite time blow up in the PDE settings is well defined if the regularity of the solution is specified. Most physically interesting scenarios demand control of the point-wise behavior of the solution. Unfortunately\, most times this level of regularity is notoriously difficult to obtain for non-linear equations. In this talk\, I will discuss very low regularity solutions namely distributional (or weak) solutions of vacuum Einsten’s equations in 3+1 dimensions. I prove that on a globally hyperbolic spacetime foliated by closed connected oriented negative Yamabe slices\, weak solutions of the Einstein equations exist for all time. The monotonicity of a Coercive Entity called reduced Hamiltonian that controls the minimum regularity required for the weak solution is employed. This is in the same spirit as Leray’s global weak solutions of Navier-Stokes in 3+1 dimensions and the first result in the context of Einstein equations.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/member-seminar-41224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Member-Seminar-04.12.2024.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240411T103000
DTEND;TZID=America/New_York:20240411T113000
DTSTAMP:20240410T234742Z
CREATED:20240410T234504Z
LAST-MODIFIED:20240410T234742Z
UID:10000886-1712831400-1712835000@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Mirror symmetry for fibrations and degenerations of K3 surfaces
DESCRIPTION:Algebraic Geometry in String Theory Seminar \nSpeaker: Alan Thompson (Loughborough University) \nTitle: Mirror symmetry for fibrations and degenerations of K3 surfaces \nAbstract: In 2016\, Doran\, Harder\, and I conjectured a mirror symmetric relationship between Tyurin degenerations and splittings of codimension 1 fibrations on Calabi-Yau manifolds. In this talk I will discuss recent work to make this conjecture rigorous in the case of K3 surfaces. I will give a precise definition of what it means for a Tyurin degeneration of K3’s to be mirror to a splitting of an elliptically fibred K3\, and show that this definition enjoys the following compatibilities with existing mirror symmetric theories: 1) The general fibre of the Tyurin degeneration is mirror to the elliptically fibred K3\, in the sense of Dolgachev-Nikulin. 2) Components of the Tyurin degeneration and pieces of the splitting satisfy a homological version of the (quasi-) Fano-LG correspondence. 3) Components of the Tyurin degeneration which are weak del Pezzo are mirror to pieces of the splitting that arise as restrictions of the corresponding lattice polarised LG models to discs. This is joint work with Luca Giovenzana.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/agst-41124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Algebraic Geometry in String Theory Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Algebraic-Geometry-in-String-Theory-04.11.2024_Page_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240405T120000
DTEND;TZID=America/New_York:20240405T130000
DTSTAMP:20240403T143010Z
CREATED:20240213T165524Z
LAST-MODIFIED:20240403T143010Z
UID:10000685-1712318400-1712322000@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Phase diagram and confining strings in a minimal model of nematopolar matter
DESCRIPTION:CMSA Member Seminar \nSpeaker: Farzan Vafa \nTitle: Phase diagram and confining strings in a minimal model of nematopolar matter \nAbstract: We investigate a minimal model of a nematopolar system. We analytically uncover a phase diagram consisting of a locked phase where the polar order and nematic order are locked\, and unlocked phases which could be ordered or disordered. In particular\, we develop two complementary perspectives on the locked phase: (i) the nematic order induces polar order\, (ii) in the locked phase\, all 1/2 integral nematic topological charges are confined. In particular\, a polar +1 defect fattens from a point along a string with constant tension and confines a pair of nematic +1/2 defects at its ends.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/member-seminar-4524/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-Member-Seminar-04.05.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240405T100000
DTEND;TZID=America/New_York:20240405T113000
DTSTAMP:20240416T141259Z
CREATED:20240329T182905Z
LAST-MODIFIED:20240416T141259Z
UID:10001513-1712311200-1712316600@live-hu-cmsa-222.pantheonsite.io
SUMMARY:Discrete geometry and the modular bootstrap
DESCRIPTION:Quantum Matter in Mathematics and Physics Seminar \nSpeaker: Henry Cohn (MIT and Microsoft) \nTitle: Discrete geometry and the modular bootstrap \nAbstract: In this talk\, I’ll discuss the remarkable connections between the modular bootstrap and sphere packing or ground state problems discovered by Hartman\, Mazáč\, and Rastelli in 2019\, with a focus on opportunities for further progress.
URL:https://live-hu-cmsa-222.pantheonsite.io/event/qm_4524/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Matter
ATTACH;FMTTYPE=image/png:https://live-hu-cmsa-222.pantheonsite.io/media/CMSA-QMMP-04.05.2024.png
END:VEVENT
END:VCALENDAR