Lab Home | Phone | Search
Center for Nonlinear Studies  Center for Nonlinear Studies
 Home 
 People 
 Current 
 Executive Committee 
 Postdocs 
 Visitors 
 Students 
 Research 
 Publications 
 Conferences 
 Workshops 
 Sponsorship 
 Talks 
 Seminars 
 Postdoc Seminars Archive 
 Quantum Lunch 
 Quantum Lunch Archive 
 P/T Colloquia 
 Archive 
 Ulam Scholar 
 
 Postdoc Nominations 
 Student Requests 
 Student Program 
 Visitor Requests 
 Description 
 Past Visitors 
 Services 
 General 
 
 History of CNLS 
 
 Maps, Directions 
 CNLS Office 
 T-Division 
 LANL 
 
Tuesday, August 12, 2008
11:00 AM - 12:00 PM
CNLS Conference Room (TA-3, Bldg 1690)

Seminar

Physics of Algorithms Talk: Front Propagation with Rejuvenation in Flipping Processes

P. L. Krapivsky
Boston University

I will describe a directed flipping process that underlies the performance of the random edge simplex algorithm. This stochastic process takes place on a one-dimensional lattice whose sites may be either occupied or vacant; an occupied site becomes vacant at a constant rate and simultaneously it causes all sites to the right to change their state. The position of the left-most occupied site defines a front that propagates at a nontrivial velocity. I will show that the front involves a depletion zone with an excess of vacant sites; the total excess increases logarithmically with the distance from the front. Interestingly, the front exhibits rejuvenation --- young fronts are vigorous but old fronts are sluggish. We treat these phenomena using a quasi-static approximation, direct solutions of small systems, and numerical simulations.

Host: T-13