Calorimetry for active systems

We provide the theoretical basis of calorimetry for a class of active particles subject to thermal noise. Simulating AC-calorimetry, we numerically evaluate the heat capacity of run-and-tumble particles in double-well and in periodic potentials, and of systems with a flashing potential. Low-temperature Schottky-like peaks show the role of activity and indicate shape transitions, while regimes of negative heat capacity appear at higher propulsion speeds. From there, a significant increase in heat capacities of active systems may be inferred at low temperatures, as well as the possibility of diagnostic tools for the activity of self-motile artificial or biomimetic systems based on heat capacity measure-ments.

Automated summary

We provide the theoretical basis for calorimetry of a class of active particles subject to thermal noise. Numerical evaluations of heat capacity of run-and-tumble particles in double-well and periodic potentials, and systems with a flashing potential are conducted, demonstrating the role of activity and indicating shape transitions. Negative heat capacity regimes are observed at higher propulsion speeds, possibly leading to an increase in heat capacities of active systems at low temperatures and potential diagnostic tools based on heat capacity measurements for self-motile artificial or biomimetic systems.