Decoherence of a two-qubit system with a variable bath coupling operator

TL;DR

This paper investigates how the symmetry of qubit-bath interactions and temperature influence decoherence in a two-qubit system with variable coupling, showing that small parameter imperfections have limited impact.

Contribution

It provides a detailed analysis of decoherence dependence on symmetry and bath configuration using the Bloch-Redfield formalism, highlighting the robustness against parameter imperfections.

Findings

Decoherence is mainly affected by symmetry and temperature.

Differences between bath configurations are minimal.

Small parameter imperfections do not significantly increase decoherence.

Abstract

We examine the decoherence of an asymmetric two-qubit system that is coupled via a tunable interaction term to a common bath or two individual baths of harmonic oscillators. The dissipative dynamics are evaluated using the Bloch-Redfield formalism. It is shown that the behaviour of the decoherence effects is affected mostly by different symmetries between the qubit operator which is coupled to the environment and temperature, whereas the differences between the two bath configurations are very small. Moreover, it is elaborated that small imperfections of the qubit parameters do not lead to a drastic enhancement of the decoherence rates.