Study of the decoherence of a double quantum dot charge qubit via the Redfield equation

TL;DR

This study uses the Redfield equation to analyze decoherence times of a double quantum dot charge qubit across different phonon environments, aligning well with experimental and exact methods.

Contribution

It applies the Redfield master equation to evaluate decoherence in a double quantum dot charge qubit for various baths, providing results consistent with experimental and exact approaches.

Findings

Decoherence times match exact path integral results for phonon baths.

Decoherence time in Ohmic bath agrees with experimental data.

Redfield equation effectively models qubit decoherence in different environments.

Abstract

By using the Redfield form of the master equation, we investigate the decoherence times of a double quantum dot charge qubit (DQDCQ) in three different cases, namely when it is coupled to (I) the piezoelectric coupling phonon bath (PCPB), (II) the deformation coupling phonon bath (DCPB), and (III) the Ohmic bath. It is found that our results for case (I) and (II) are in the same magnitude with those obtained via the exact path integral methods, while for case (III), the decoherence time is in well agreement with the experimental value.