Open quantum dynamics of Josephson charge pumps

TL;DR

This paper models the quantum dynamics of Josephson charge pumps using an open quantum system approach, incorporating electrostatic interactions, and finds qualitative agreement with experimental data, advancing understanding of quantum charge pumping mechanisms.

Contribution

It introduces a Markovian master equation framework for Josephson charge pumps that includes nonlinear capacitive effects, providing a more realistic description of their dynamics.

Findings

Qualitative agreement with experimental observations

Inclusion of electrostatic interactions improves modeling accuracy

Highlights broader significance in active charge pumping systems

Abstract

We investigate the macroscopic dynamics of Josephson charge pumps in the light of Alicki et al.'s theoretical description of the Josephson junction as an open quantum system described by a Markovian master equation. Once the electrostatic interaction between the terminals is taken into account via nonlinear capacitive terms in the Hamiltonian, we find that the resulting description of pumping is physically reasonable and in good qualitative agreement with experimental observations. We comment on how this approach relates to other theoretical treatments of quantum pumps based on time-dependent potentials or scattering amplitudes. We also highlight the significance of our results in the broader context of the dynamics of charge pumping by active systems.