Active Brownian Particles:  Probing the Boundaries Between Equilibrium and Nonequilibrium Thermodynamics

Particles that exhibit a mechanism to convert free energy into directed propulsion are known as Active Brownian Particles (ABPs).  ABPs are a nonequilibrium generalization of Brownian motion and, at sufficient propulsion strengths, show a motility-induced phase separation that resembles a gas-liquid transition in equilibrium.  Understanding the stochastic thermodynamics of ABPs systems has been an important topic in recent years.  In this talk, we will derive the Langevin equation for such a particle and the corresponding Fokker-Plank equation.  We will also develop an analytical framework for predicting motility-induced phase separation.