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X-WR-CALDESC:Events for CMSA
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BEGIN:VTIMEZONE
TZID:America/New_York
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TZOFFSETFROM:-0500
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DTSTART:20180311T070000
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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191009T163000
DTEND;TZID=America/New_York:20191009T173000
DTSTAMP:20260523T194812
CREATED:20240212T101721Z
LAST-MODIFIED:20240514T175345Z
UID:10001968-1570638600-1570642200@cmsa.fas.harvard.edu
SUMMARY:Global Existence and Scattering for Einstein's equations and related equations satisfying the weak null condition
DESCRIPTION:Speaker: Hans Lindblad (Johns Hopkins University) \nTitle:  Global Existence and Scattering for Einstein’s equations and related equations satisfying the weak null condition \nAbstract: Einstein’s equations in harmonic or wave coordinates are a system of nonlinear wave equations for a Lorentzian metric\, that in addition satisfy the preserved wave coordinate condition. Christodoulou-Klainerman proved global existence for Einstein vacuum equations for small asymptotically flat initial data. Their proof avoids using coordinates since it was believed the metric in harmonic coordinates would blow up for large times. John had noticed that solutions to some nonlinear wave equations blow up for small data\, whereas Klainerman came up with the ‘null condition’\, that guaranteed global existence for small data. However Einstein’s equations do not satisfy the null condition. Hormander introduced a simplified asymptotic system by neglecting angular derivatives which we expect decay faster due to the rotational invariance\, and used it to study blowup. I showed that the asymptotic system corresponding to the quasilinear part of Einstein’s equations does not blow up and gave an example of a nonlinear equation of this form that has global solutions even though it does not satisfy the null condition. Together with Rodnianski we introduced the ‘weak null condition’ requiring that the corresponding asymptotic system have global solutions and we showed that Einstein’s equations in wave coordinates satisfy the weak null condition and we proved global existence for this system. Our method reduced the proof to a fraction and has now been used to prove global existence also with matter fields. \nRecently I derived precise asymptotics for the metric which involves logarithmic corrections to the radiation field of solutions of linear wave equations. We are further imposing these asymptotics at infinity and solve the equations backwards to obtain global solutions with given data at infinity.
URL:https://cmsa.fas.harvard.edu/event/10-9-2019-colloquium/
LOCATION:MA
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.09.19-2-789x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191009T151500
DTEND;TZID=America/New_York:20191009T161500
DTSTAMP:20260523T194812
CREATED:20240212T111415Z
LAST-MODIFIED:20240221T103022Z
UID:10002048-1570634100-1570637700@cmsa.fas.harvard.edu
SUMMARY:10/9/2019 RM & PT Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-9-2019-rm-pt-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191009T150000
DTEND;TZID=America/New_York:20191009T160000
DTSTAMP:20260523T194812
CREATED:20240213T113140Z
LAST-MODIFIED:20240304T110658Z
UID:10002503-1570633200-1570636800@cmsa.fas.harvard.edu
SUMMARY:10/9/2019 Fluid Dynamics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-9-2019-fluid-dynamics-seminar/
LOCATION:MA
CATEGORIES:Fluid Dynamics Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191009T103000
DTEND;TZID=America/New_York:20191009T120000
DTSTAMP:20260523T194812
CREATED:20240212T110952Z
LAST-MODIFIED:20240212T180524Z
UID:10002041-1570617000-1570622400@cmsa.fas.harvard.edu
SUMMARY:10/9/2019 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-9-2019-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Quantum Matter,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191007T120000
DTEND;TZID=America/New_York:20191007T130000
DTSTAMP:20260523T194812
CREATED:20240212T102220Z
LAST-MODIFIED:20240221T111224Z
UID:10001975-1570449600-1570453200@cmsa.fas.harvard.edu
SUMMARY:10/7/2019 Math-Physics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-7-2019-math-physics-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191004T150000
DTEND;TZID=America/New_York:20191004T150000
DTSTAMP:20260523T194812
CREATED:20240212T100954Z
LAST-MODIFIED:20240221T092312Z
UID:10001959-1570201200-1570201200@cmsa.fas.harvard.edu
SUMMARY:10/4/2019 Special Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-4-2019-special-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191003T163000
DTEND;TZID=America/New_York:20191003T170000
DTSTAMP:20260523T194812
CREATED:20240212T095706Z
LAST-MODIFIED:20240221T091326Z
UID:10001945-1570120200-1570122000@cmsa.fas.harvard.edu
SUMMARY:10/3/2019 RM & PT Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-3-2019-rm-pt-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191003T143000
DTEND;TZID=America/New_York:20191003T150000
DTSTAMP:20260523T194812
CREATED:20240212T100021Z
LAST-MODIFIED:20240212T100021Z
UID:10001948-1570113000-1570114800@cmsa.fas.harvard.edu
SUMMARY:10/3/2019 Spacetime Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-3-2019-spacetime-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191003T120000
DTEND;TZID=America/New_York:20191003T130000
DTSTAMP:20260523T194812
CREATED:20240212T103007Z
LAST-MODIFIED:20240221T110055Z
UID:10001985-1570104000-1570107600@cmsa.fas.harvard.edu
SUMMARY:10/3/2019 Condensed Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-3-2019-condensed-matter-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191002T163000
DTEND;TZID=America/New_York:20191002T173000
DTSTAMP:20260523T194812
CREATED:20240212T101431Z
LAST-MODIFIED:20240530T194159Z
UID:10001965-1570033800-1570037400@cmsa.fas.harvard.edu
SUMMARY:Cohomologies on almost complex manifolds and their applications 
DESCRIPTION:Speaker: Spiro Karigiannis (University of Waterloo)\n\n\nTitle: Cohomologies on almost complex manifolds and their applications\n\nAbstract: We define three cohomologies on an almost complex manifold (M\, J)\, defined using the Nijenhuis-Lie derivations induced from the almost complex structure J and its Nijenhuis tensor N\, regarded as vector-valued forms on M. One of these can be applied to distinguish non-isomorphic non-integrable almost complex structures on M. Another one\, the J-cohomology\, is familiar in the integrable case but we extend its definition and applicability to the case of non-integrable almost complex structures. The J-cohomology encodes whether a complex manifold satisfies the “del-delbar-lemma”\, and more generally in the non-integrable case the J-cohomology encodes whether (M\, J) satisfies a generalization of this lemma. We also mention some other potential cohomologies on almost complex manifolds\, related to an interesting question involving the Nijenhuis tensor. This is joint work with Ki Fung Chan and Chi Cheuk Tsang.
URL:https://cmsa.fas.harvard.edu/event/10-2-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.02.19-791x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20191002T103000
DTEND;TZID=America/New_York:20191002T120000
DTSTAMP:20260523T194812
CREATED:20240212T102559Z
LAST-MODIFIED:20240221T110855Z
UID:10001981-1570012200-1570017600@cmsa.fas.harvard.edu
SUMMARY:10/2/2019 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/10-2-2019-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190930T120000
DTEND;TZID=America/New_York:20190930T130000
DTSTAMP:20260523T194812
CREATED:20240212T101743Z
LAST-MODIFIED:20240221T111707Z
UID:10001969-1569844800-1569848400@cmsa.fas.harvard.edu
SUMMARY:9/30/2019 Math-Physics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-30-2019-math-physics-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190926T143000
DTEND;TZID=America/New_York:20190926T150000
DTSTAMP:20260523T194812
CREATED:20240212T103326Z
LAST-MODIFIED:20240221T105655Z
UID:10001990-1569508200-1569510000@cmsa.fas.harvard.edu
SUMMARY:9/26/2019 Spacetime Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-26-2019-spacetime-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190926T120000
DTEND;TZID=America/New_York:20190926T150000
DTSTAMP:20260523T194812
CREATED:20240212T103730Z
LAST-MODIFIED:20240212T103730Z
UID:10001996-1569499200-1569510000@cmsa.fas.harvard.edu
SUMMARY:9/26/2019 Condensed Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-26-2019-condensed-matter-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190926T120000
DTEND;TZID=America/New_York:20190926T130000
DTSTAMP:20260523T194812
CREATED:20240212T104221Z
LAST-MODIFIED:20240212T104221Z
UID:10002001-1569499200-1569502800@cmsa.fas.harvard.edu
SUMMARY:9/26/2019 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-26-2019-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190925T163000
DTEND;TZID=America/New_York:20190925T173000
DTSTAMP:20260523T194812
CREATED:20240212T104035Z
LAST-MODIFIED:20240514T175737Z
UID:10001999-1569429000-1569432600@cmsa.fas.harvard.edu
SUMMARY:Double affine Hecke algebras
DESCRIPTION:Speaker: Pavel Etingof (MIT)\n\nTitle:  Double affine Hecke algebras\n\nAbstract: Double affine Hecke algebras (DAHAs) were introduced by I. Cherednik in the early 1990s to prove Macdonald’s conjectures. A DAHA is the quotient of the group algebra of the elliptic braid group attached to a root system by Hecke relations. DAHAs and their degenerations are now central objects of representation theory. They also have numerous connections to many other fields — integrable systems\, quantum groups\, knot theory\, algebraic geometry\, combinatorics\, and others. In my talk\, I will discuss the basic properties of double affine Hecke algebras and touch upon some applications.\n\n\n\n  \n 
URL:https://cmsa.fas.harvard.edu/event/9-25-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-09.25.19-791x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190925T150000
DTEND;TZID=America/New_York:20190925T160000
DTSTAMP:20260523T194812
CREATED:20240212T103156Z
LAST-MODIFIED:20240212T103156Z
UID:10001987-1569423600-1569427200@cmsa.fas.harvard.edu
SUMMARY:9/25/2019 Fluid Dynamics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-25-2019-fluid-dynamics-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190925T140800
DTEND;TZID=America/New_York:20190925T140800
DTSTAMP:20260523T194812
CREATED:20240212T104438Z
LAST-MODIFIED:20240212T104438Z
UID:10002007-1569420480-1569420480@cmsa.fas.harvard.edu
SUMMARY:9/25/2019 RM&PT Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-25-2019-rmpt-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190925T120000
DTEND;TZID=America/New_York:20190925T130000
DTSTAMP:20260523T194812
CREATED:20240212T104728Z
LAST-MODIFIED:20240212T104728Z
UID:10002011-1569412800-1569416400@cmsa.fas.harvard.edu
SUMMARY:9/25/2019 Math-Physics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-25-2019-math-physics-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190925T103000
DTEND;TZID=America/New_York:20190925T120000
DTSTAMP:20260523T194812
CREATED:20240212T103430Z
LAST-MODIFIED:20240212T103430Z
UID:10001991-1569407400-1569412800@cmsa.fas.harvard.edu
SUMMARY:9/25/2019 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-25-2019-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190920T103000
DTEND;TZID=America/New_York:20190920T113000
DTSTAMP:20260523T194812
CREATED:20240212T102847Z
LAST-MODIFIED:20240212T102847Z
UID:10001984-1568975400-1568979000@cmsa.fas.harvard.edu
SUMMARY:9/20/2019 General Relativity Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-20-2019-general-relativity-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190919T143000
DTEND;TZID=America/New_York:20190919T160000
DTSTAMP:20260523T194812
CREATED:20240212T094800Z
LAST-MODIFIED:20240212T094800Z
UID:10001932-1568903400-1568908800@cmsa.fas.harvard.edu
SUMMARY:9/19/2019 Spacetime Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-19-2019-spacetime-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190918T163000
DTEND;TZID=America/New_York:20190918T173000
DTSTAMP:20260523T194812
CREATED:20240212T102253Z
LAST-MODIFIED:20240514T175908Z
UID:10001976-1568824200-1568827800@cmsa.fas.harvard.edu
SUMMARY:A taste of noncommutative convex algebraic geometry
DESCRIPTION:Speaker: Bill Helton (UC San Diego)\n\nTitle:  A taste of noncommutative convex algebraic geometry\n\nAbstract: The last decade has seen the development of a substantial noncommutative (in a free algebra) real and complex algebraic geometry. The aim of the subject is to develop a systematic theory of equations and inequalities for (noncommutative) polynomials or rational functions of matrix variables. Such issues occur in linear systems engineering problems\, in free probability (random matrices)\, and in quantum information theory. In many ways the noncommutative (NC) theory is much cleaner than classical (real) algebraic geometry. For example\,\n\n◦ A NC polynomial\, whose value is positive semidefinite whenever you plug matrices into it\, is a sum of squares of NC polynomials.\n◦ A convex NC semialgebraic set has a linear matrix inequality representation.\n◦ The natural Nullstellensatz are falling into place.\n\n The goal of the talk is to give a taste of a few basic results and some idea of how these noncommutative problems occur in engineering. The subject is just beginning and so is accessible without much background. Much of the work is joint with Igor Klep who is also visiting CMSA for the Fall of 2019.
URL:https://cmsa.fas.harvard.edu/event/9-18-2019-colloquium/
LOCATION:CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-09.12.19-791x1024-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190918T150000
DTEND;TZID=America/New_York:20190918T160000
DTSTAMP:20260523T194812
CREATED:20240212T102025Z
LAST-MODIFIED:20240212T102025Z
UID:10001973-1568818800-1568822400@cmsa.fas.harvard.edu
SUMMARY:9/18/2019 Fluid Dynamics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-18-2019-fluid-dynamics-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190918T103000
DTEND;TZID=America/New_York:20190918T120000
DTSTAMP:20260523T194812
CREATED:20240212T102513Z
LAST-MODIFIED:20240212T102513Z
UID:10001980-1568802600-1568808000@cmsa.fas.harvard.edu
SUMMARY:9/18/2019 Quantum Matter Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-18-2019-quantum-matter-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190916T120000
DTEND;TZID=America/New_York:20190916T130000
DTSTAMP:20260523T194812
CREATED:20240212T094504Z
LAST-MODIFIED:20240212T094504Z
UID:10001928-1568635200-1568638800@cmsa.fas.harvard.edu
SUMMARY:9/16/2019 Math-Physics Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-16-2019-math-physics-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190913T103000
DTEND;TZID=America/New_York:20190913T233000
DTSTAMP:20260523T194812
CREATED:20240212T095003Z
LAST-MODIFIED:20240212T095003Z
UID:10001935-1568370600-1568417400@cmsa.fas.harvard.edu
SUMMARY:9/13/2019 General Relativity
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-13-2019-general-relativity/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190912T173800
DTEND;TZID=America/New_York:20190912T173800
DTSTAMP:20260523T194812
CREATED:20240213T102851Z
LAST-MODIFIED:20240213T102851Z
UID:10002429-1568309880-1568309880@cmsa.fas.harvard.edu
SUMMARY:Spacetime and Quantum Mechanics Seminar
DESCRIPTION:As part of the program on Spacetime and Quantum Mechanics\, the CMSA will be hosting a weekly seminar on Thursdays at 2:30pm in room G10. \n\n\n\nDate\nSpeaker\nTitle/Abstract\n\n\n9/12/2019\nPasha Pylyavskyy (University of Minnesota)\nTitle: Vector-relation configurations and plabic graphs\n\n\n19/18/2019 \n2:00pm \nG02\nFrancis Brown (University of Oxford)\nTitle: Amplitudes\, Polylogs and Moduli Spaces\n\n\n9/19/2019\nChuck Doran (University of Alberta)\nTitle: Calabi-Yau geometry of the N-loop sunset Feynman integrals \nAbstract: I will present an overview of the algebraic and transcendental features of the computation of N-loop sunset Feynman integrals. \nStarting from the realization of arbitrary Feynman graph hypersurfaces as (generalized) determinantal varieties\, we describe the Calabi-Yau subvarieties of permutohedral varieties that arise from the N-loop sunset Feynman graphs and some key features of their geometry and moduli. \nThese include: (1) an iterated fibration structure which allows one to “bootstrap” both periods and Picard-Fuchs equations from lower N cases; (2) specialization to and interpretation of coincident mass loci (“jump loci”) in moduli; (3) a significant generalization of the Griffiths-Dwork algorithm via “creative telescoping”; and (4) the realization of Calabi-Yau pencils as Landau-Ginzburg models mirror to weak Fano varieties. \nDetails of each of these will be discussed in later lectures this semester. This is joint work with Pierre Vanhove and Andrey Novoseltsev.\n\n\n9/26/2019\nTomasz Taylor (Northeastern)\nTitle: Celestial Amplitudes\n\n\n10/3/2019\nSimon Caron-Huot (McGill)\nTitle: Poincare Duals of Feynman Integrals\n\n\n10/10/2019 \n3:30pm\nYutin Huang (National Taiwan University)\nTitle: Dualities of Planar Ising Networks and the Positive Orthogonal Grassmannian\n\n\n10/15/2019 \nTuesday \n3:30pm\n  \nSergey Fomin (Univ. of Michigan) \n \nTitle: “Morsifications and mutations” (joint work with P. Pylyavskyy\, E. Shustin\, and D. Thurston). \n\n\n10/18/2019 \nFriday  \nG02\nSebastian Franco (The City College of New York)\nTitle: Graded quivers\, generalized dimer models\, and topic geometry\n\n\n10/31/2019\nJunjie Rao (Albert Einstein Institute)\nTitle: All-loop Mondrian Reduction of 4-particle Amplituhedron at Positive Infinity\n\n\n11/1/2019 \nSC 232 \n1:30pm\nGeorge Lusztig (MIT)\nTitle: Total positivity in Springer fibres\n\n\n11/12/2019 \nTuesday \nG02 \n3:30pm\n  \nPierpaolo Mastrolia (University of Padova)\nTitle: Feynman Integrals and Intersection Theory\n\n\n11/14/2019 \nG02\nPierpaolo Mastrolia (University of Padova)\nTitle: Feynman Integrals and Intersection Theory Pt. II\n\n\n11/21/2019\nCristian Vergu (Niels Bohr Institute)\nTitle: The Octagonal Alphabet\n\n\n11/26/2019\nStephan Stieberger (IAS)\nTitle: Strings on the Celestial Sphere\n\n\n12/4/2019\nHadleigh Frost (Oxford)\nTitle: BCJ numerators\, $\mathcal{M}_{0\,n}$\, and ABHY \nAbstract: We relate the BCJ numerator Jacobi property to the classical fact that the top homology group of $\mathcal{M}_{0\,n}$ is isomorphic to a component of the free Lie algebra. We describe ways to get BCJ numerators\, and caution that the BCJ Jacobi property doesn’t imply the existence of what has been called a ‘kinematic algebra.’\n\n\n 12/5/2019\nDavid Kosower (IAS)\nTitle: From scattering amplitudes to classical observables\n\n\n12/10/2019\nRamis Movassagh (MIT)\nTitle: Highly entangled quantum spin chains: Exactly solvable counter-examples to the area law \nAbstract: In recent years\, there has been a surge of activities in proposing “exactly solvable” quantum spin chains with surprising high amount of ground state entanglement–exponentially more than the critical systems that have $\log(n)$ von Neumann entropy. We discuss these models from first principles. For a spin chain of length $n$\, we prove that the ground state entanglement entropy scales as $\sqrt(n)$ and in some cases even extensive (i.e.\, as $n$) despite the underlying Hamiltonian being: (1) Local (2) Having a unique ground state and (3) Translationally invariant in the bulk. These models have rich connections with combinatorics\, random walks\, Markov chains\, and universality of Brownian excursions. Lastly\, we develop techniques for proving the gap. As a consequence\, the gap of Motzkin and Fredkin spin chains are proved to vanish as 1/n^c with c>2; this rules out the possibility of these models to be relativistic conformal field theories in the continuum limit. Time permitting we will discuss more recent developments in this direction and ‘generic’ aspects of local spin chains.
URL:https://cmsa.fas.harvard.edu/event/spacetime-and-quantum-mechanics-seminar/
LOCATION:MA
CATEGORIES:Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190912T143000
DTEND;TZID=America/New_York:20190912T160000
DTSTAMP:20260523T194812
CREATED:20240212T095136Z
LAST-MODIFIED:20240212T095136Z
UID:10001937-1568298600-1568304000@cmsa.fas.harvard.edu
SUMMARY:9/12/2019 Spacetime Seminar
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-12-2019-spacetime-seminar/
LOCATION:MA
CATEGORIES:Colloquia & Seminar,Seminars
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20190911T134500
DTEND;TZID=America/New_York:20190911T144500
DTSTAMP:20260523T194812
CREATED:20240212T094226Z
LAST-MODIFIED:20240212T094226Z
UID:10001925-1568209500-1568213100@cmsa.fas.harvard.edu
SUMMARY:9/11/2019 Random Matrix
DESCRIPTION:
URL:https://cmsa.fas.harvard.edu/event/9-11-2019-random-matrix/
LOCATION:MA
CATEGORIES:Random Matrix & Probability Theory Seminar,Seminars
END:VEVENT
END:VCALENDAR