| Talk_id | Date | Speaker | Title |
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31564
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Wednesday 2/8
4:10 PM
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Alexander Volberg, MSU
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Noncommutative Bohnenblust--Hille inequalities and application to learning the quantum observables
- Alexander Volberg, MSU
- Noncommutative Bohnenblust--Hille inequalities and application to learning the quantum observables
- 02/08/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
(Virtual Meeting Link)
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
Bohnenblust--Hille inequalities for Boolean cubes have been proven with dimension-free constants that grow sub-exponentially in the degree (Defant—Mastylo—Peres). Such inequalities have found great applications in learning low degree Boolean functions (Eskenazis—Ivanisvili). Motivated by learning quantum observables, a quantum counterpart of Bohnenblust--Hille inequality for Boolean cubes was recently conjectured in Cambyse Rouz\’e, Melchior Wirth, and Haonan Zhang: ``Quantum Talagrand, KKL and Friedgut’s theorems and the learnability of quantum Boolean functions.” arXiv preprint, arXiv:2209.07279, 2022.
Haonan Zhang and myself prove such noncommutative Bohnenblust--Hille inequalities with constants that are dimension-free and of exponential growth in the degree. As applications, we study learning problems of quantum observables.
(Speaker will present remotely)
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31555
|
Wednesday 3/1
4:10 PM
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Zhongshan An, U. Mich
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Quasi-local Hamiltonians for compact initial data sets
- Zhongshan An, U. Mich
- Quasi-local Hamiltonians for compact initial data sets
- 03/01/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
In general relativity, one of the most interesting ways to construct notions of energy is the method of Hamiltonian analysis. For asymptotically flat spacetimes, this approach yields the well-known ADM mass. In order to define quasi-local energy/mass for compact initial data sets, one would like to apply the Hamiltonian analysis of GR on compact spacetimes with time-like boundary. Traditionally, this has been done based on fixing the Dirichlet boundary condition of the spacetimes — one of the most well-known work along this thread is the Brown-York quasi-local mass. In this talk we will discuss in detail the relation between the study of initial boundary value problem for vacuum Einstein equations and the Hamiltonian analysis on compact spacetimes. Then we will construct a notion of quasi-local Hamiltonian (energy) based on a well-posed initial boundary value problem.
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30461
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Wednesday 3/22
4:10 PM
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Katrina Morgan, Northwestern University
|
Wave propagation on rotating cosmic string spacetimes
- Katrina Morgan, Northwestern University
- Wave propagation on rotating cosmic string spacetimes
- 03/22/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
A rotating cosmic string spacetime has a singularity along a timelike curve corresponding to a one-dimensional source of angular momentum. Such spacetimes are not globally hyperbolic: they admit closed timelike curves near the so-called "string". This presents challenges to studying the existence of solutions to the wave equation via conventional energy methods. In this work, we show that forward solutions to the wave equation (in an appropriate microlocal sense) do exist. Our techniques involve proving a statement on propagation of singularities and using the resulting estimates to show existence of solutions. This is joint work with Jared Wunsch.
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32611
|
Wednesday 3/29
4:10 PM
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Sung-Jin Oh, UC Berkeley
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TBA
- Sung-Jin Oh, UC Berkeley
- TBA
- 03/29/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
TBA
|
|
29400
|
Wednesday 4/5
4:10 PM
|
Matt Jacobs, Purdue
|
TBA
- Matt Jacobs, Purdue
- TBA
- 04/05/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
- Olga Turanova (turanova@msu.edu)
TBA
|
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29385
|
Wednesday 4/12
4:10 PM
|
Leonardo Abbrescia, Vanderbilt University
|
A localized picture of the maximal development for shock forming solutions of the 3D compressible Euler equations
- Leonardo Abbrescia, Vanderbilt University
- A localized picture of the maximal development for shock forming solutions of the 3D compressible Euler equations
- 04/12/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
(Virtual Meeting Link)
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
Understanding the behavior of solutions to the compressible Euler equations for large times necessitates a sharp analysis of possible singularities that can form. Our understanding of shock singularities in three space dimensions has enjoyed a dramatic surge in progress in the past two decades due in part to the mathematical techniques that were developed to study Einstein’s equations. In this talk, I will discuss my recent work which provides a sharp localized description of a shock singularity as part of the boundary of maximal development of smooth data. The set of Cartesian spacetime points on which a singularity occurs, which we call the singular boundary $\mathcal{B}$, has the structure of an embedded hypersurface with very degenerate causal properties. I will give an overview of the difficulties that occur in the construction of the singular boundary, and if time permits, also discuss the construction of the Cauchy horizon which emanates from the past boundary of $\mathcal{B}$.
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32593
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Wednesday 4/19
4:10 PM
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Olga Turanova , MSU
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TBA
- Olga Turanova , MSU
- TBA
- 04/19/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
TBA
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30452
|
Wednesday 4/26
4:10 PM
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Yakov Shlapentokh-Rothman, University of Toronto
|
TBA
- Yakov Shlapentokh-Rothman, University of Toronto
- TBA
- 04/26/2023
- 4:10 PM - 5:00 PM
- C304 Wells Hall
- Willie Wai-Yeung Wong (wongwil2@msu.edu)
TBA
|
