Non-markovian dynamics of double quantum dot charge qubit with static bias

TL;DR

This paper theoretically investigates the non-Markovian dynamics of a charge qubit in a double quantum dot with static bias, revealing how bias and phonon coupling influence coherence and decoherence.

Contribution

It introduces a perturbation approach based on unitary transformations to explicitly derive the dynamical tunneling current in biased double quantum dot systems.

Findings

Bias increases the coherence-incoherence transition point.

Reducing phonon coupling enhances coherence frequency and prolongs coherence time.

Applying static bias helps maintain quantum coherence.

Abstract

The dynamics of charge qubit in double quantum dot coupled to phonons is investigated theoretically. The static bias is considered. By means of the perturbation approach based on unitary transformations, the dynamical tunneling current is obtained explicitly. The biased system displays broken symmetry and a significantly larger coherence-incoherence transition critical point $\alpha _{c}$. We also analyzed the decoherence induced by piezoelectric coupling phonons in detail. The results show that reducing the coupling between system and bath make coherence frequency increase and coherence time prolong. To maintain quantum coherence, applying static bias also is a good means.