Diffusion of wave packets in a Markov random potential

Speaker: 

Yang Kang

Institution: 

Michigan State University

Time: 

Thursday, November 6, 2008 - 2:00pm

Location: 

RH 306

In this talk, we consider the evolution of a tight binding wave packet propagating in a time dependent potential. We assume the potential evolves according to a stationary Markov process and show that the square amplitude of the wave packet converges to a solution of a heat equation. This is joint work with Jeff Schenker.

WENO type limiters for discontinuous Galerkin methods

Speaker: 

Professor Jianxian Qiu

Institution: 

Nanjing University

Time: 

Thursday, October 2, 2008 - 4:00pm

Location: 

RH 306

In the presentation we will describe our recent work on a class of new limiters, called
WENO (weighted essentially non-oscillatory) type limiters, for Runge-Kutta discontinuous
Galerkin (RKDG) methods. The goal of designing such limiters is to obtain a robust and
high order limiting procedure to simult

Polynomials defining distinguished varieties

Speaker: 

Dr. Greg Knese

Institution: 

UCI

Time: 

Tuesday, October 28, 2008 - 3:00pm

Location: 

RH 306

"Distinguished varieties" are a special class of algebraic
curves in C^2 that exit the bidisk through the distinguished boundary
(aka the torus). We shall discuss connections with the polynomials
that define these curves and polynomials with no zeros on the bidisk,
and use a powerful "sums of squares" formula (actually a two variable
version of the Christoffel-Darboux formula for orthogonal polynomials)
to a prove a determinantal representation of distinguished varieties.
As an application of our approach, we will prove a certain bounded
analytic "extension" theorem.

Periodic Homogenization of Nonlinear Integro-Differential Equations

Speaker: 

Dr. Russell Schwab

Institution: 

University of Texas at Austin

Time: 

Tuesday, November 4, 2008 - 3:00pm

Location: 

RH 306

We consider the homogenization for a very general class of
nonlinear, nonlocal "elliptic" equations. Motivated by the techniques
of the homogenization of fully nonlinear uniformly elliptic second order
equations by Caffarelli- Souganidis- Wang, we show how a nonlocal
version of an obstacle problem can be used to identify the effective
equation in the nonlocal setting.

Properties of the effective Hamiltonian and the connection with the Aubrey-Mather theory

Speaker: 

Professor Yifeng Yu

Institution: 

UC Irvine

Time: 

Tuesday, October 21, 2008 - 3:00pm

Location: 

RH 306

I will first give a brief introduction of the connection between
a Hamilton-Jacobi equation and the Aubrey-Mather theory. This is the so
called weak KAM theory. An extremely interesting project in weak KAM
theory is to understand what kind of dynamical information is encoded in
the
effective Hamiltonian. I will present a result about the connection
between linear pieces on level curves of the effective Hamiltonian and the
structure of correspondent Aubry sets.

Decay of waves on black hole backgrounds

Speaker: 

Professor Daniel Tataru

Institution: 

University of California Berkeley

Time: 

Thursday, November 13, 2008 - 4:00pm

Location: 

RH 306

The Schwarzchild, respectively the Kerr space-times are solutions for the vacuum Einstein equation which model a spherically symmetric, respectively a rotating black hole. In this talk I will discuss the decay properties of solutions to the linear wave equation on
such backgrounds.

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