Biological & Soft Matter Seminar: Anomalous thermal relaxations in over-damped Langevin dynamics, antiferromagnets, and Random Energy Models

Abstarct:

Rapid cooling or heating of a physical system to its environment can lead to unusual thermal relaxation phenomena, which we call anomalous. A prime example of anomalous thermal relaxation is the Mpemba effect. The phenomenon occurs in cooling when a system prepared at a hot temperature overtakes an identical system prepared at a warm temperature and equilibrates faster to the cold environment. A similar effect exists in heating. Comparing two identical physical systems in their relaxation to the environment, we would expect that the system with a smaller mismatch between its and the environment's temperature will thermalize faster -- yet it is not always the case. The effect was observed in various physical systems, including water, magnetic systems, clathrate hydrates, polymers, and colloidal particle systems. My talk will overview this exciting phenomenon and recent research efforts. I will then present theoretical results on the Mpemba effect for over-damped Langevin dynamics, antiferromagnets in the mean field, and the Random Energy Model. I will link the Mpemba effect's occurrence with the system's physical properties, such as the shape of the potential in the over-damped Langevin dynamics and the phase transitions in the antiferromagnet. 

*This material is based upon work supported by the National Science Foundation under Grant No. DMR-1944539.