Speaker: S. Beheshti, Rutgers University - on leave from Tata
Institute, Mumbai India Date/Time/Place: Tuesday, Mar. 3, 2009, 12:00pm, Hill 705 Title: Introduction to Gravitational Solitons Abstract:We follow the main lines of the classical paper by
Belinskii and Zakharov [JETP 48(6) 1978] with the intent of
introducing the audience to Gravitational Solitons, a subject of much
interest for the past 30 years. Extension of the inverse scattering
method (ISM) to the theory of gravitation has afforded a systematic
study of soliton solutions to the Einstein equations based upon their
symmetries. We give an outline of the ISM in this setting, discuss
several general properties of gravitational solitons and indicate
avenues for further reading and investigation.
Speaker: O. Bruno, Caltech Date/Time/Place: Thursday, Mar. 5, 2009, 12:00pm, Hill 705 Title:Integral equations in regular and singular domains
Abstract: The numerical solution of wave-propagation and scattering problems
typically presents a variety of significant challenges: these problems
require high discretization densities and often give rise to poorly
conditioned numerics. Realistic engineering configurations, further,
usually require consideration of geometries of great complexity and
large extent - including, possibly, singular elements such as wires,
corners, edges and open screens. In this talk we will consider a
number of theoretical aspects concerning these problems as well as
associated computational methodologies that effectively address the
difficulties entailed.
THERE WILL BE A BROWN BAG LUNCH FROM 1:00 - 2:00PM.
PLEASE JOIN US
Speaker: D. Holcman, Weizmann Institute Date/Time/Place: Thursday, Mar. 5, 2009, 2:00pm, Hill 705 Title: Modeling viral trafficking in the cytoplasm
Abstract: Intracellular transport of DNA carriers is a fundamental step of gene delivery. By combining both theoretical and numerical approaches we study here single and several viruses and DNA particles trafficking in the cell cytoplasm to a small nuclear pore.
I would like to present a physical model to account for certain aspects of cellular organization, starting with the observation that a viral trajectory consists of epochs of pure diffusion and epochs of active transport along microtubules.
By replacing the switching dynamics by a single steady state stochastic
description, we obtain estimates for the probability and the mean time for the first one of many particles to go from the cell membrane to a small nuclear pore. Computational simulations confirm that our model can be
used to analyze and interpret viral trajectories and estimate quantitatively the success of nuclear delivery.
Speaker: N. Zanghi, Rutgers University Date/Time/Place: Thursday, Mar. 12, 2009, 12:00pm, Hill 705 Title: Schroedinger's First Quantum Theory
Abstract:Schroedinger's first proposal for the interpretation
of quantum
mechanics was based on a postulate relating the wave function on
configuration space to charge density in physical space. Schroeodinger
apparently later thought that his proposal was empirically
wrong. Recent
work done in collaboration with V. Allori, S. Goldstein and R. Tumulka
suggests that maybe this conclusion was too hasty, at least for a very
similar proposal with charge density replaced by mass density.
THERE WILL BE NO MATHEMATICAL PHYSICS SEMINAR ON
THURSDAY, MARCH 19, 2009 DUE TO SPRING BREAK
SPECIAL SEMINAR, TUESDAY 3/24/09
Speaker: O. Costin, Ohio State University Date/Time/Place: Tuesday, Mar. 24, 2009, 12:00pm, Hill 705 Title: Gamow Vectors and Borel Summation Abstract: Please click HERE for abstract.
Speaker: R. Costin, Onio State University Date/Time/Place: Thursday, Mar. 26, 2009, 12:00pm, Hill 705 Title: Differential systems with Fuchsian linear part:
correction and linearization, normal forms and matrix valued
orthogonal polynomials Abstract:Differential systems with a Fuchsian linear part are
studied in regions including all the singularities in the complex
plane of these equations. Such systems are not necessarily analytically
equivalent to their linear part (they are not linearizable) and
obstructions are found as a unique nonlinear correction after which
the system becomes formally linearizable. More generally, normal forms
are found.
Linearizability of differential equations is closely related to
integrability.
The corrections and the normal forms of are generated constructively,
using expansions in sequences of matrix-valued polynomials which turn
out to have many of the properties associated to classical orthogonal
polynomials.
Definition of orthogonality for the classical Jacobi polynomials for
general weights will also be discussed.
THERE WILL BE A BROWN BAG LUNCH FROM 1:00 - 2:00PM.
PLEASE JOIN US
Speaker: D. Bucholtz, University of Goettingen Date/Time/Place: Thursday, Mar. 26, 2009, 2:00pm, Hill 705 Title: Warped Convolutions: A novel tool in the construction of
quantum field theories
Abstract:Recently, Grosse and Lechner introduced a deformation procedure for
non-interacting quantum field theories, giving rise to interesting examples
of theories with non-trivial scattering matrix in any number of
spacetime dimensions. In this talk we outline
an extension of this procedure to the general framework of quantum field
theory by introducing the concept of "warped" convolutions of operator
functions. These convolutions have some intriguing properties which permit the
deformation of arbitrary nets of algebras based on wedge-shaped
regions of Minkowski space to nets which still satisfy Einstein's
principles of relativistic covariance and causality. The deformed nets still
admit a scattering theory and give rise to a deformed scattering matrix.