Double quantum dot coupled to a quantum point contact: A stochastic thermodynamics approach

TL;DR

This paper investigates the nonequilibrium thermodynamics of a double quantum dot coupled to a quantum point contact, revealing fluctuation theorems and the impact of non-interacting electrons on device efficiency.

Contribution

It introduces a stochastic thermodynamics framework for a DQD-QPC system, demonstrating local detailed balance and fluctuation theorems in this context.

Findings

Transition rates satisfy local detailed balance.

Energy and particle current statistics obey a fluctuation theorem.

Non-interacting electrons significantly affect efficiency.

Abstract

We study the nonequilibrium properties of an electronic circuit composed of a double quantum dot (DQD) channel coupled to a quantum point contact (QPC) within the framework of stochastic thermodynamics. We show that the transition rates describing the dynamics satisfy a nontrivial local detailed balance (LDB) and that the statistics of energy and particle currents across both channels obeys a fluctuation theorem (FT). We analyze two regimes where the device operates as a thermodynamic machine and study its output power and efficiency fluctuations. We show that the electrons tunneling through the QPC without interacting with the DQD have a strong effect on the device efficiency.