TITLE:

ORDER IN REACTION-DIFFUSION SYSTEMS AWAY FROM EQUILIBRIUM (No. 46)

DATE:

Friday, May 7th, 2004

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Katja Lindenberg, Department of Chemistry and Biochemistry, University of California, San Diego

ABSTRACT:

The past few years have seen the emergence of dramatically

counterintuitive phenomena in even the “simplest” complex systems away from thermodynamic equilibrium. Among these systems are ones in which diffusing or subdiffusing species undergo chemical reactions or other reaction-like interactions, hydrodynamic systems, and other systems of chemical interest. The observations are counterintuitive in that they lead to outcomes that are exactly opposite to those one might expect. Several examples will be discussed as time permits, including:

1) Phase transitions to ordered or patterned states caused NOISE in reactive systems that exhibit no order in the absence of noise;

2) Turing instabilities (the quintessential instability leading topattern formation in chemical and hydrodynamic systems) triggered by simple switching between dynamics that by themselves are completely stable and unpatterned. These phenomena are illustrated via numerical simulations and understood in terms of mean field theories that capture these behaviors qualitatively and in some cases even quantitatively.

HOST:

Peter Salamon

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