Pressure in Non-equilibrium (Active) Systems

Pressure is the mechanical force per unit area that a confined system exerts on its container. In thermal equilibrium, the pressure depends only on bulk properties (density, temperature, etc.) through an equation of state. The talk will show that in active systems, containing self-propelled particles, the pressure can depend on the precise interactions between the particles and the confining walls.  This implies that generic active systems have no equation of state. Other anomalous attributes of pressure will also be discussed.

Finally, time permitting, it will be shown that in certain fine tuned cases an equation of state can be recovered. The physics behind the equation of state in a specific example will be discussed.