Seminar by Professor Gil ARIEL (Bar Ilan University)

Entropy production quantifies irreversibility in stochastic systems and has been shown to be related to heat dissipation and the amount of extractable work in active systems. However, measuring entropy production in experiments is challenging due to the effectively high dimensionality of the problem. We consider two well-studied examples of living active systems - swarming bacteria and human bronchial epithelial cells. We show that topological defects in the cells' orientation field can be used as physically intuitive, coarse graining of the dynamics. The entropy production of defect trajectories can be measured using direct statistical methods, revealing that defect creation and annihilation are not reversible and act as a major source of entropy production.