Field theories of active particle systems and their entropy production

Understand

Active particles that translate chemical energy into self-propulsion can maintain a far-from-equilibrium steady state and perform work.

• The entropy production measures how far from equilibrium such a particle system operates and serves as a proxy for the work performed.
• Field theory offers a promising route to calculating entropy production, as it allows for many interacting particles to be considered simultaneously.
• Approximate field theories obtained by coarse-graining or smoothing that draw on additive noise can capture densities and correlations well, but they generally ignore the microscopic particle nature of the constituents, thereby producing spurious results for the entropy production.