Temperature dependence of long coherence times of oxide charge qubits

TL;DR

This paper demonstrates theoretically that oxide charge qubits can maintain long coherence times even above liquid helium boiling point by tuning system parameters and considering non-Markovian effects.

Contribution

It introduces a theoretical model showing how to achieve long coherence times in oxide charge qubits at higher temperatures than previously possible.

Findings

Long coherence times are achievable above boiling point of liquid helium.

Detuning and electron-phonon coupling influence coherence times.

Decoherence occurs despite no energy exchange with the phonon bath.

Abstract

The ability to maintain coherence and control in a qubit is a major requirement for quantum computation. We show theoretically that long coherence times can be achieved above boiling point of liquid helium in charge qubits of oxide double quantum dots. Detuning the dots to a fraction of the optical phonon energy, increasing the electron-phonon coupling, reducing the adiabaticity, or decreasing the temperature enhances the coherence time. We consider a system that is initially decoupled from the phonon bath in the polaronic frame of reference and solve the non-Markovian quantum master equation; we find that the system decoheres after a long time, despite the fact that no energy is exchanged with the bath.