Nonequilibrium free energy and information flow of a double quantum-dot system with Coulomb coupling* *Project supported by the National Natural Science Foundation (Grant No. 11805159), the First Batch of National First-class Undergraduate Courses of China (2020), the Natural Science Foundation of Fujian Province, China (Grant No. 2019J05003), and Teaching Research Program of Thermodynamics and Statistical Physics in the Institution of

Abstract

We build a double quantum-dot system with Coulomb coupling and aim at studying connections among the entropy production, free energy, and information flow. By utilizing concepts in stochastic thermodynamics and graph theory analysis, Clausius and nonequilibrium free energy inequalities are built to interpret local second law of thermodynamics for subsystems. A fundamental set of cycle fluxes and affinities is identified to decompose two inequalities by using Schnakenberg’s network theory. Results show that the thermodynamic irreversibility has energy-related and information-related contributions. A global cycle associated with the feedback-induced information flow would pump electrons against the bias voltage, which implements a Maxwell demon.