• Symmetry in quantum field theory and quantum gravity 1

    Speaker: Daniel Harlow (MIT) Title: Symmetry in quantum field theory and quantum gravity 1 Abstract: In this talk I will give an overview of semi-recent work with Hirosi Ooguri arguing that three old conjectures about symmetry in quantum gravity are true in the AdS/CFT correspondence.  These conjectures are 1) that there are no global symmetries in […]

  • Compactness and Anticompactness Principles in Set Theory

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    Member Seminar Speaker: Alejandro Poveda Title: Compactness and Anticompactness Principles in Set Theory Abstract: Several fundamental properties in Topology, Algebra or Logic are expressed in terms of Compactness Principles.For instance, a natural algebraic question is the following: Suppose that G is an Abelian group whose all small subgroups are free - Is the group G free? […]

  • Exact Many-Body Ground States from Decomposition of Ideal Higher Chern Bands: Applications to Chirally Twisted Graphene Multilayers

    Virtual

    Quantum Matter Seminar Speaker: Junkai Dong (Harvard University) Title: Exact Many-Body Ground States from Decomposition of Ideal Higher Chern Bands: Applications to Chirally Twisted Graphene Multilayers Abstract: Motivated by the higher Chern bands of twisted graphene multilayers, we consider flat bands with arbitrary Chern number C with ideal quantum geometry. While C>1 bands differ from […]

  • IIB Explored – Dualities, Bordisms, and the Swampland

    Jefferson 356

    Swampland Seminar Location: Jefferson Physical Laboratory, Seminar room J356 Speaker: Markus Dierigl (LMU Munich) Title: IIB Explored - Dualities, Bordisms, and the Swampland Abstract: In this talk I will discuss the application of the Cobordism Conjecture to type IIB supergravity with non-trivial duality bundle. Calculating the relevant bordism groups we find that they are highly non-trivial and […]

  • Neutrino Masses from Generalized Symmetry Breaking

    Virtual

    Quantum Matter Seminar Speaker: Sungwoo Hong (U Chicago & KAIST) Title: Neutrino Masses from Generalized Symmetry Breaking Abstract: We explore generalized global symmetries in theories of physics beyond the Standard Model. Theories of Z′ bosons generically contain 'non-invertible' chiral symmetries, whose presence indicates a natural paradigm to break this symmetry by an exponentially small amount […]

  • Controlling Quantum Matter with Quantum Cavity Fields

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    https://youtu.be/Ig468DbAVGs Topological Quantum Matter Seminar Speaker: Vasil Rokaj (Harvard) Title: Controlling Quantum Matter with Quantum Cavity Fields Abstract: Cavity modification of material properties and phenomena is a novel research field motivated by the advances in strong light-matter interactions . For condensed matter systems it has been demonstrated experimentally that the transport properties of 2D materials […]

  • How do Transformers reason? First principles via automata, semigroups, and circuits

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    https://youtu.be/g8zdumOAWzw New Technologies in Mathematics Seminar Speaker: Cyril Zhang, Microsoft Research Title: How do Transformers reason? First principles via automata, semigroups, and circuits Abstract: The current "Transformer era" of deep learning is marked by the emergence of combinatorial and algorithmic reasoning capabilities in large sequence models, leading to dramatic advances in natural language understanding, program synthesis, […]

  • Fourier quasicrystals and stable polynomials

    Harvard Science Center 1 Oxford Street, Cambridge, MA

    Probability Seminar Note location change: Science Center Room 300H Speaker: Lior Alon (MIT) Title: Fourier quasicrystals and stable polynomials Abstract: The Poisson summation formula says that the countable sum of exp(int), over all integers n, vanishes as long as t is not an integer multiple of 2 pi. Can we find a non-periodic discrete set A, such […]

  • A new proof for the nonlinear stability of slowly-rotating Kerr-de Sitter

    Virtual

    https://youtu.be/jwvkS2A2dL8 General Relativity Seminar Speaker: Allen Fang (Princeton) Title: A new proof for the nonlinear stability of slowly-rotating Kerr-de Sitter Abstract: The nonlinear stability of the slowly-rotating Kerr-de Sitter family was first proven by Hintz and Vasy in 2016 using microlocal techniques. In my talk, I will present a novel proof of the nonlinear stability […]

  • Self-organization of motile cells by quorum-sensing or chemotactic interactions

    Active Matter Seminar Speaker: Julien Tailleur (MIT) Title: Self-organization of motile cells by quorum-sensing or chemotactic interactions Abstract: Equilibrium statistical mechanics tells us how to control the self-assembly of passive materials by tuning the competition between energy and entropy to achieve desired states of organization. Out of equilibrium, no such principles apply and self-organization principles are […]

  • Non-Invertible Symmetries from Holography and Branes

    Virtual

    Quantum Matter Seminar Speaker: Federico Bonetti (Oxford) Title: Non-Invertible Symmetries from Holography and Branes Abstract:  The notion of global symmetry in quantum field theory (QFT) has witnessed dramatic generalizations in the past few years. One of the most exciting developments has been the identification of 4d QFTs possessing non-invertible symmetries, i.e. global symmetries whose generators […]

  • Phase Fluctuations in Two-Dimensional Superconductors and Pseudogap Phenomenon

    Virtual

    Quantum Matter Seminar Speaker: Yang Qi (Fudan) Title: Phase Fluctuations in Two-Dimensional Superconductors and Pseudogap Phenomenon Abstract: We study the phase fluctuations in the normal state of a general two-dimensional (2d) superconducting system with s-wave pairing. The effect of phase fluctuations of the pairing fields can be dealt with perturbatively using disorder averaging, after we […]