Towards a 'Thermodynamics' of Active Matter

Abstract

Self-propulsion allows living systems to display unusual collective behavior. Unlike passive systems in thermal equilibrium, active matter systems are not constrained by conventional thermodynamic laws. A question arises however as to what extent, if any, can concepts from classical thermodynamics be applied to nonequilibrium systems like active matter. Here we use the new swim pressure perspective to develop a simple theory for predicting phase separation in active matter. Using purely mechanical arguments we generate a phase diagram with a spinodal and critical point, and define a nonequilibrium chemical potential to interpret the "binodal." We provide a generalization of thermodynamic concepts like the free energy and temperature for nonequilibrium active systems. Our theory agrees with existing simulation data both qualitatively and quantitatively and may provide a framework for understanding and predicting the behavior of nonequilibrium active systems.

5 pages, 5 figures

References in corpus (2)

• Statistical Mechanics of Interacting Run-and-Tumble Bacteria
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation

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• Morphology of clusters of attractive dry and wet self-propelled spherical particle suspensions
• Applicability of Effective Pair Potentials for Active Brownian Particles
• Non-Equilibrium Surface Tension of the Vapour-Liquid Interface of Active Lennard-Jones Particles
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• Active Brownian particles at interfaces: An effective equilibrium approach
• Phase coexistence of active Brownian particles
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• Kinetics of motility-induced phase separation and swim pressure
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• Swimming to Stability: Structural and Dynamical Control via Active Doping
• How irreversible are steady-state trajectories of a trapped active particle?
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• Statistical mechanics of transport processes in active fluids: Equations of hydrodynamics
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• Phase separation of active Brownian particles in two dimensions: Anything for a quiet life
• Active dry granular flows: rheology and rigidity transitions
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• Anti-Swarming: Structure and Dynamics of Repulsive Chemically Active Particles
• Self-organization of active colloids mediated by chemical interactions
• Shear induced migration of microswimmers in pressure-driven channel flow
• Active ploughing through a compressible viscoelastic fluid: Unjamming and emergent nonreciprocity