Adiabatic processes realized with a trapped Brownian particle

TL;DR

This paper experimentally demonstrates quasistatic adiabatic processes with a trapped micro-sphere, analyzing heat and entropy fluctuations, and distinguishing between different definitions of adiabaticity in stochastic thermodynamics.

Contribution

It provides the first experimental realization of adiabatic processes with a trapped particle and compares two definitions, offering analytical and experimental insights into heat and entropy fluctuations.

Findings

Heat distribution is asymmetric in non-isothermal processes.

Only phase space volume preservation leads to zero average heat and entropy change.

The entropy change distribution depends on the degrees of freedom considered.

Abstract

We experimentally realize quasistatic adiabatic processes using a single optically-trapped micro- sphere immersed in water whose effective temperature is controlled by an external random electric field. A full energetic characterization of adiabatic processes that preserve either the position dis- tribution or the full phase space volume is presented. We show that only in the latter case the exchanged heat and the change in the entropy of the particle vanish when averaging over many repetitions. We provide analytical expressions for the distributions of the fluctuating heat and en- tropy, which we verify experimentally. We show that the heat distribution is asymmetric for any non-isothermal quasistatic process. Moreover, the shape of the distribution of the system entropy change in the adiabatic processes depends significantly on the number of degrees of freedom that are considered for the calculation of system entropy.