Computations in Science Seminars

Wednesdays at KPTC 206, unless otherwise specified

The Kersten Physics Teaching Center is on the corner of 57th Street and Ellis Avenue.

Discussion over bag-lunch at 12:15 PM. Talk starts at 12:30 PM.

INFORMATION FOR SPEAKERS

Upcoming seminars

Previous seminars

This seminar series is organized by David Biron, email address, Wendy Zhang, email address, and Leo Kadanoff, email address.

 A photo of M51 Galaxy

Whirlpool Galaxy M51
September 10, 2008
Konstantin Turitsyn, University of Chicago
e-mail: email address
Vesicle Dynamics in External Flows
Dynamics of vesicles in external flows has been a subject of great experimental and theoretical attention recently. A vesicle can exhibit a variety of different dynamical behaviors when placed in an external flow. At least three qualitative different motions have been observed in recent experiments: tumbling, tank-treading, trembling. I will review these experiments and will present a theoretical analysis of this effect, resulting in a phase-diagram which predicts the type of the vesicle motion. For planar external flows, the character of the vesicle dynamics is determined by two dimensionless parameters, which are formed out of viscosities of inner and outer fluids, external velocity gradient matrix and vesicle excess area. Transitions between different types of motions are analyzed separately. The tank-treading to tumbling transition is described by a saddle-node bifurcation whereas the tank-treading to trembling transition occurs via a Hopf bifurcation. In the vicinity of the transition lines the vesicle experiences critical slowing down, which can be described universal scaling exponents. In the end of the talk I will also discuss the effect of vesicle wrinkling in extensional flows.
September 17, 2008
Michael Marder, University of Texas
e-mail: email address, Faculty contact: Leo Kadanoff, email address
Student Flows in Texas
Texas, like all other states, has been gathering test data on public school students for many years. What can one do with test records from 4 million students? I have been visualizing math test scores using ideas loosely borrowed from statistical mechanics and fluid mechanics. The visual representations give a more complete picture than is obtained by focusing on single numbers. They make it possible to address questions about the relative importance of income levels, race, and other factors in the Texas public K-12 educational system, and about whether testing pressure is improving educational performance. I will also comment on local, state, and national efforts in which I have been involved to better educate science and mathematics teachers.
September 24, 2008
Lee Smolin, Perimeter Institute for Theoretical Physics
e-mail: email address, Faculty contact: Leo Kadanoff, email address
Quantum Gravity as a Problem in Critical Phenomena
Several current approaches to quantum gravity construct or derive models of quantum spacetime as discrete quantum systems on dynamical lattices. The key problem to be resolved in these models is whether and how classical spacetime arises from a discrete quantum system. This problem of the emergence of spacetime in the low energy limit is thus a problem in critical phenomena. I will introduce some of the models of quantum spacetime of current interest and illustrate the progress being made using them towards the problem of the emergence of classical spacetime. I will emphasize an important question, which is currently the subject of experimental probes, which is the symmetry of the ground state: is it Poincare, broken Poincare or quantum deformed Poincare?
September 29, 2008 (Joint seminar with MRSEC: 12:30 in KPTC 206)
Itai Cohen, Cornell University
e-mail: email address, Faculty contact: Leo Kadanoff, email address
October 1, 2008
Doug Smith
e-mail: email address, Faculty contact: Leo Kadanoff, email address
October 8, 2008
Leo Kadanoff, University of Chicago
e-mail: email address
Problems in Geometry and Analysis in 2-D: Fun with Charges and Eigenvectors
There is a simple, exact solution to the problem of how charge arranges itself on the surface of a conductor. Put discrete charges on a pointy surface and you have a problem in modern mathematics.
There is a simple, exact solution to an eigenvalues problem for a matrix M(j,k) when that matrix is constant along any diagonal and its indices run from minus infinity to infinity. Make the matrix finite but large and you have a problem in modern mathematics.
We (Hui Dai, Zachery Geary, LPK) attacked this problem by constructing eigenvectors for a particular case in which the infinite matrix is singular. The matrix indices run from 0 to N-1; we construct exact eigenvectors for the analogous problem with indices running from zero to infinity. We then speculate about the general form of these vectors in the finite-N case. The speculations are mostly verified by comparison with exact calculations of eigenvectors.
October 15, 2008
Dmitri Talapin, University of Chicago
e-mail: email address
October 22, 2008
Berni Alder, Lawrence Livermore National Laboratory
e-mail: email address, Faculty contact: Leo Kadanoff, email address
October 29, 2008 (^)
Petia Vlahovska, Dartmouth College
e-mail: email address, Faculty contact: Wendy Zhang, email address
November 5, 2008 (^)
Benoit Roman, Ecole Superieure de Physique et de Chimie Industrielles
e-mail: email address, Faculty contact: Tom Witten, email address
November 12, 2008 (^)
Pedro Reis, Massachusetts Institute of Technology
e-mail: email address, Faculty contact: Ka Yee Lee, email address
November 19, 2008
(open date)
November 21, 2008 (Special Seminar: 12:30 in KPTC 206)
Detlef Lohse, University of Twente
e-mail: email address, Faculty contact: Leo Kadanoff, email address
December 3, 2008
V. Ramanathan, University of California, San Diego
e-mail: email address, Faculty contact: Leo Kadanoff, email address
January 7, 2009
(open date)
January 14, 2009
Marcelo Magnasco, Rockefeller University
e-mail: email address, Faculty contact: Leo Kadanoff, email address
January 21, 2009
Margaret Gardel, University of Chicago
e-mail: email address
January 28, 2009
Aaron Dinner, University of Chicago
e-mail: email address
February 4, 2009
(open date)
February 11, 2009
Daniel Rothman, Massachusetts Institute of Technology
e-mail: email address, Faculty contact: Leo Kadanoff, email address
February 18, 2009
(open date)
February 25, 2009
(open date)
March 4, 2009
(open date)
March 11, 2009
(open date)
March 18, 2009 (During APS March Meeting)
(open date)
March 25, 2009
(open date)

(&) : When Wendy Zhang is unavailable for the seminar.

(^) : When Leo Kadanoff is unavailable for the seminar.

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