Full counting statistics of the currents through a Kitaev chain and the exchange fluctuation theorem

TL;DR

This paper analytically derives the full counting statistics and exchange fluctuation theorems for currents in a Kitaev chain connected to reservoirs, revealing how symmetry-breaking terms influence transport processes.

Contribution

It provides the first analytical calculation of full counting statistics and formulates exchange fluctuation theorems for a Kitaev chain with symmetry-breaking terms.

Findings

Different forms of XFTs emerge due to U(1) symmetry breaking.

Analytical expressions for transport current statistics are obtained.

Numerical results confirm the theoretical predictions.

Abstract

Exchange fluctuation theorems (XFTs) describe a fundamental symmetry relation for particle and energy exchange between several systems. Here we study the XFTs of a Kitaev chain connected to two reservoirs in the same temperature but different bias. By varying the parameters in the Kitaev chain model, we calculate analytically the full counting statistics of the transport current and formulate the corresponding XFTs for multiple current components. We also demonstrate the XFTs with numerical results. We find that due to the presence of the U(1) symmetry breaking terms in the Hamiltonian of the Kitaev chain, various forms of the XFTs emerge, and they can be interpreted in terms of various well-known transport processes.