**Haim Diamant (Tel Aviv University) | **Using entropy to study systems out of thermal equilibrium |

Abstract:

Thermodynamic variables such as temperature and pressure are ill-defined out of thermal equilibrium. However, the relation between entropy and the information contained in the statistical distribution of the system’s microstates is assumed to hold regardless of whether or not the system is at equilibrium. Therefore, entropy should be a useful global property for characterizing non-equilibrium behaviors.

We have obtained, based on first principles, a universal inequality relating the entropy of a system at steady state and the diffusion coefficient of its constituents. The relation can be used to obtain useful bounds for the diffusion coefficient (normal or anomalous) from the calculated thermodynamic entropy or, conversely, to estimate the entropy based on measured diffusion coefficients. We demonstrate the validity and applicability of the relation in several examples.

We have derived a functional which takes as input measurable pair-correlations (such as the structure factor) and gives a useful upper bound for the entropy. We use it to pin-point and characterize dynamic transitions in several experimental and computational systems, including driven and active particles.

When: March 15, 2023 2:00 PM (Israel Standard Time).

__Where:__ Room 223, Multipurpose Bldg. & over Zoom