• Friday, October 7, 2022
  • 09:30 AM
Category: Algebraic Geometry in String Theory
Speaker: Sam Bardwell-Evans, Boston University
Title: Scattering Diagrams from Holomorphic Discs in Log Calabi-Yau Surfaces
Algebraic Geometry in String Theory Seminar Speaker: Sam Bardwell-Evans, Boston University Title: Scattering Diagrams from Holomorphic Discs in Log Calabi-Yau Surfaces Abstract: In this talk, we construct special Lagrangian fibrations for log Calabi-Yau surfaces and scattering diagrams from Lagrangian Floer theory of the fibers. These scattering diagrams recover the algebro-geometric scattering diagrams of Gross-Pandharipande-Siebert and Gross-Hacking-Keel. The argument relies on a holomorphic/tropical disc correspondence to control the behavior of holomorphic discs, allowing us to relate open Gromov-Witten invariants to log Gromov-Witten invariants. This talk is based on joint work with Man-Wai Mandy Cheung, Hansol Hong, and Yu-Shen Lin.
  • Friday, October 7, 2022
  • 11:00 AM
Category: Member Seminar
Speaker: Zhigang Yao, Harvard CMSA
Title: Principal flow, sub-manifold and boundary
Member Seminar  Speaker: Zhigang Yao Title: Principal flow, sub-manifold and boundary Abstract: While classical statistics has dealt with observations which are real numbers or elements of a real vector space, nowadays many statistical problems of high interest in the sciences deal with the analysis of data which consist of more complex objects, taking values in spaces which are naturally not (Euclidean) vector spaces but which still feature some geometric structure. I will discuss the problem of finding principal components to the multivariate datasets, that lie on an embedded nonlinear Riemannian manifold within the higher-dimensional space. The aim is to extend the geometric interpretation of PCA, while being able to capture the non-geodesic form of variation in the data. I will...
  • Tuesday, October 11, 2022
  • 11:00 AM
Category: Swampland Seminar
Speaker: Aasmund Folkestad, MIT
Title: The Penrose Inequality as a Constraint on Low Energy Quantum Gravity
Swampland Seminar Speaker: Aasmund Folkestad (MIT) Title: The Penrose Inequality as a Constraint on Low Energy Quantum Gravity Abstract: In this talk, I argue that the Penrose inequality (PI) can be used to constrain low energy theories compatible AdS/CFT, and possibly also quantum gravity in flat space. Focusing on AdS/CFT, it is shown that the PI can be violated for minimally coupled scalar fields, and I produce exclusion plots on couplings that respect the PI. I also present numerical evidence that top-down scalar theories and supersymmetric theories respect the PI. Finally, similar to the Breitenlohner-Freedman bound, I give a necessary condition for the stability AdS that constrains coupling constants (beyond the scalar mass).
  • Wednesday, October 12, 2022
  • 09:00 AM
Category: Topological Quantum Matter Seminar
Speaker: Jennifer Cano, Stony Brook and Flatiron Institute
Title: Engineering topological phases with a superlattice potential
Topological Quantum Matter Seminar Speaker: Jennifer Cano (Stony Brook and Flatiron Institute) Title: Engineering topological phases with a superlattice potential Abstract: We propose an externally imposed superlattice potential as a platform for manipulating topological phases, which has both advantages and disadvantages compared to a moire superlattice. In the first example, we apply the superlattice potential to the 2D surface of a 3D topological insulator. The superlattice potential creates tunable van Hove singularities, which, when combined with strong spin-orbit coupling and Coulomb repulsion give rise to a topological meron lattice spin texture. Thus, the superlattice potential provides a new route to the long sought-after goal of realizing spontaneous magnetic order on the surface of a 3D TI. In the second example, we...
  • Wednesday, October 12, 2022
  • 12:30 PM
Category: Colloquia
Speaker: James Cummings, Carnegie Mellon University
Title: Complete disorder is impossible: Some topics in Ramsey theory
Colloquium Title: Complete disorder is impossible: Some topics in Ramsey theory Speaker: James Cummings, Carnegie Mellon University Abstract: The classical infinite Ramsey theorem states that if we colour pairs of natural numbers using two colours, there is an infinite set all of whose pairs get the same colour. This is the beginning of a rich theory, which touches on many areas of mathematics including graph theory, set theory and dynamics. I will give an overview of Ramsey theory, emphasizing the diverse ideas which are at play in this area.
  • Friday, October 14, 2022
  • 09:30 AM
Category: Algebraic Geometry in String Theory
Speaker: Daniel Pomerleano, UMass Boston
Title:
Algebraic Geometry in String Theory Seminar Speaker: Daniel Pomerleano, UMass Boston
  • Friday, October 14, 2022
  • 11:00 AM
Category: Member Seminar
Speaker: Leonid Rybnikov, Harvard CMSA
Title: Member Seminar: Title TBA
Speaker: Leonid Rybnikov
  • Wednesday, October 19, 2022
  • 12:30 PM
Category: Colloquia
Speaker: TBA
Title: Colloquium: Title TBA
Colloquium
  • Wednesday, October 19, 2022
  • 04:00 PM
Category: Topological Quantum Matter Seminar
Speaker: Yizhuang You, UC San Diego
Title: Symmetric Mass Generation
Topological Quantum Matter Seminar Speaker: Yizhuang You, UC San Diego Title: Symmetric Mass Generation Abstract: Symmetric mass generation (SMG) is a novel mechanism for massless fermions to acquire a mass via a strong-coupling non-perturbative interaction effect. In contrast to the conventional Higgs mechanism for fermion mass generation, the SMG mechanism does not condense any fermion bilinear coupling and preserves the full symmetry. It is connected to a broad range of topics, including anomaly cancellation, topological phase classification, and chiral fermion regularization. In this talk, I will introduce SMG through toy models, and review the current understanding of the SMG transition. I will also mention recent numerical efforts to investigate the SMG phenomenon. I will conclude the talk with...
  • Friday, October 21, 2022
  • 09:30 AM
Category: Algebraic Geometry in String Theory
Speaker: Nicolo Piazzalunga, Rutgers
Title:
Algebraic Geometry in String Theory Seminar Speaker:Nicolo Piazzalunga, Rutgers
  • Friday, October 21, 2022
  • 11:00 AM
Category: Member Seminar
Speaker: David Zuckerman, Harvard CMSA
Title: Member Seminar: Title TBA
Speaker: David Zuckerman
  • Wednesday, October 26, 2022
  • 09:00 AM
Category: Topological Quantum Matter Seminar
Speaker: Bruno Mera, Tohoku University
Title: Kähler bands—Chern insulators, holomorphicity and induced quantum geometry
Topological Quantum Matter Seminar Speaker: Bruno Mera, Tohoku University Title: Kähler bands—Chern insulators, holomorphicity and induced quantum geometry Abstract: The notion of topological phases has dramatically changed our understanding of insulators. There is much to learn about a band insulator beyond the assertion that it has a gap separating the valence bands from the conduction bands. In the particular case of two dimensions, the occupied bands may have a nontrivial topological twist determining what is called a Chern insulator. This topological twist is not just a mathematical observation, it has observable consequences—the transverse Hall conductivity is quantized and proportional to the 1st Chern number of the vector bundle of occupied states over the Brillouin zone. Finer properties of band...
  • Friday, October 28, 2022
  • 09:30 AM
Category: Algebraic Geometry in String Theory
Speaker: Ahsan Khan, IAS
Title:
Algebraic Geometry in String Theory Seminar Speaker: Ahsan Khan, IAS
  • Friday, October 28, 2022
  • 11:00 AM
Category: Member Seminar
Speaker: Shuaijie Qian, Harvard CMSA
Title: Member Seminar: Title TBA
Speaker: Shuaijie Qian
  • Friday, November 4, 2022
  • 11:00 AM
Category: Member Seminar
Speaker: Mauricio Romo, Harvard CMSA
Title: Member Seminar: Title TBA
Speaker: Mauricio Romo