Incomplete current fluctuation theorems for a four-terminal model

TL;DR

This paper demonstrates the validity of current fluctuation theorems in a four-terminal quantum dot system, exploring conditions where the theorem appears violated when only partial currents are observed.

Contribution

It extends fluctuation theorem analysis to a four-terminal quantum dot model with phonon-assisted tunneling beyond the Coulomb-blockade regime.

Findings

Fluctuation theorem holds for the full current set.

Apparent violations occur when only partial currents are monitored.

Thermodynamic parameters can drive currents against gradients.

Abstract

We demonstrate the validity of the current fluctuation theorem for a double quantum dot surrounded by four terminals within the Born-, Markov- and secular approximations beyond the Coulomb-blockade regime. The electronic tunneling to two fermionic contacts conserves the total number of electrons, and the internal tunneling is phonon-assisted by two bosonic baths. Adapted choice of thermodynamic parameters between the baths may drive a current against an existing electric or thermal gradient. We study the apparent violation of the fluctuation theorem when only some of the energy and matter currents are monitored.