Thomas Speck, Robert L. Jack
Published 2015-12-02Version 1
The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here we study the simplest model, an ideal gas of non-interacting active Brownian particles, and carefully consider the role of boundary conditions. While previously the pressure has been linked to correlations, we argue that these correlations are entirely controlled by boundary effects. The local bulk pressure of an active and passive ideal gas are the same, which precludes an equation of state predicting the pressure exerted on walls. We point out consequences for systems with internal walls.
On Brownian motion in ideal gas and related principles
A probabilistic model for the equilibration of an ideal gas
The Frustration of being Odd: How Boundary Conditions can destroy Local Order
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