# Events for 11/22/2019 from all calendars

## Mathematical Physics and Harmonic Analysis Seminar

**Time:** 1:50PM - 2:50PM

**Location:** BLOC 628

**Speaker:** Jonas Luhrmann, Texas A&M University

**Title:** *Stability of kinks and dispersive decay of Klein-Gordon waves*

**Abstract:** Kinks are particle-like solitons that arise in nonlinear scalar field theories in one space dimension. In this talk I will explain how the study of the asymptotic stability of kinks centers on the long-time behavior of small solutions to one-dimensional Klein-Gordon equations with variable coefficient nonlinearities. Then I will present a new result on sharp decay estimates and asymptotics for small solutions to variable coefficient cubic nonlinear Klein-Gordon equations. If time permits, I will also discuss work in progress on the variable coefficient quadratic case, which exhibits a striking resonant interaction between the spatial oscillations of the variable coefficient and the temporal oscillations of the solutions. This is joint work with Hans Lindblad and Avy Soffer.

## Student/Postdoc Working Geometry Seminar

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 624

**Speaker:** A. Pal, TAMU

**Title:** *Mukai 11/22*

## Novel Medical Imaging Workshop

**Time:** 2:30PM - 5:00PM

**Location:** BLOC 220

**URL:** *Link*

## Algebra and Combinatorics Seminar

**Time:** 3:00PM - 3:50PM

**Location:** BLOC 628

**Title:**

## Noncommutative Geometry Seminar

**Time:** 3:00PM - 4:00PM

**Location:** BLOC 624

**Speaker:** Ilya Kachkovskiy, Michigan State University

**Title:** *Almost commuting matrices*

**Abstract:** Suppose that $X$ and $Y$ are two self-adjoint matrices with the commutator $[X,Y]$ of small operator norm. One would expect that $X$ and $Y$ are close to a pair of commuting matrices. Can one provide a distance estimate which only depends on $\|[X,Y]\|$ and not on the dimension? This question was asked by Paul Halmos in 1976 and answered positively by Huaxin Lin in 1993 by indirect C*-algebraic methods, which did not provide any explicit bounds. It was conjectured by Davidson and Szarek that the distance estimate would be of the form $C\|[X,Y]\|^{1/2}$. In the talk, I will explain some background on this and related problems, and the main ideas of the proof of this conjecture, obtained jointly with Yuri Safarov. If time permits, I will discuss some current work in progress.

## Student Working Seminar in Groups and Dynamics

**Time:** 3:00PM - 4:00PM

**Location:** BLOC 605AX

**Speaker:** Josiah Owens

**Title:** *Weak Mixing Extensions of Szemeredi Factors*

## Geometry Seminar

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 628

**Speaker:** Guillem Cazassus, Indiana University

**Title:** *Equivariant Lagrangian Floer homology and extended Field theory*

**Abstract:** Given a Hamiltonian G-manifold endowed with a pair of G-Lagrangians, we provide a construction for their equivariant Floer homology. Such groups have been defined previously by Hendricks, Lipshitz and Sarkar, and also by Daemi and Fukaya. A similar construction appeared independently in the work of Kim, Lau and Zheng. We will discuss an attempt to use such groups to construct topological Field theories: these should be seen as 3-morphism spaces in the Hamiltonian 3-category, which should serve as a target for a Field theory corresponding to Donaldson polynomials.

## Linear Analysis Seminar

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 624 ***

**Speaker:** Priyanga Ganesan, TAMU

**Title:** *Quantum Majorization in Infinite Dimensions*

**Abstract:** Majorization is a concept from linear algebra that is used to compare disorderness in physics, computer science, economics and statistics. Recently, Gour et al (2018) extended matrix majorization to the quantum mechanical setting to accommodate ordering of quantum states. In this talk, I will discuss a generalization of their definition and entropic characterization of quantum majorization to the infinite dimensional setting, using operator space tensor products and duality. This is based on joint work with Li Gao, Satish Pandey and Sarah Plosker.