statistical mechanics

I was in two exams today. The first was a candidacy exam for Henrique Moyses (NYU), who is working on the stochastic vortex, a response of random-walking particles to non-conservative forces. One of the main problems he has is how to measure the drift velocity field of a particle, when the secular drift is a tiny, tiny fraction of the random velocity. He has lots of samples, but fitting the steady part (mean) of the spatially varying stochastic velocity distribution function is not trivial. We vowed to discuss density estimation in January.

The second exam was a PhD defense for Ivane Jorjadze (NYU), who has various results on systems of jammed particles. He has worked out quantitatively a thermodynamic analogy for non-thermal but randomly packed solids with some specific experimental systems. He has also worked out the elasticity and normal modes of jammed soft particles (like cells). Beautiful stuff, with good physics content and also very relevant to biological systems. Congratulations Dr. Jorjadze!