Dynamics of interacting transport qubits

TL;DR

This paper explores how a charge qubit influences electron transport, entanglement, and steady states in coupled double quantum dots, revealing ways to control and stabilize quantum states via voltages.

Contribution

It introduces a detailed analysis of the interplay between a charge qubit and transport quantum dots using a quantum master equation approach, highlighting control over entanglement and purity.

Findings

Qubit modifies coherent tunnel amplitudes in quantum dots.

Steady state currents exhibit signatures of the qubit.

Pure entangled states can be stabilized in Coulomb diamonds.

Abstract

We investigate the electronic transport through two parallel double quantum dots coupled both capacitively and via a perpendicularly aligned charge qubit. The presence of the qubit leads to a modification of the coherent tunnel amplitudes of each double quantum dot. We study the influence of the qubit on the electronic steady state currents through the system, the entanglement between the transport double quantum dots, and the back action on the charge qubit. We use a Born-Markov-Secular quantum master equation for the system. The obtained currents show signatures of the qubit. The stationary qubit state may be tuned and even rendered pure by applying suitable voltages. In the Coulomb diamonds it is also possible to stabilize pure entangled states of the transport double quantum dots.