Decoherence of a Driven Qubit

TL;DR

This paper investigates how driving a qubit influences its decoherence rates in the presence of environmental noise, revealing that driving parameters can either accelerate or reduce decoherence depending on the noise spectrum and driving conditions.

Contribution

The study provides a general theoretical framework for understanding driven qubit decoherence, including effects of detuning, phase shift, and environmental noise spectral density, with specific application to spin qubits in quantum dots.

Findings

Driving modifies decoherence rates, enabling control over dissipation and dephasing.

Decoherence can be accelerated or suppressed by tuning driving parameters.

Electrical noise and spin-orbit coupling significantly affect spin relaxation in quantum dots.

Abstract

We study decoherence of a field-driven qubit in the presence of environmental noises. For a general qubit, we find that driving, whether on-resonance or off-resonance, alters the qubit decoherence rates (including dissipation and pure dephasing), allowing both blue and red sideband contributions from the reservoir. Depending on the noise spectral density, driving field detuning and driving field phase shift, the qubit decoherence rates could be either accelerated or reduced. We apply our general theory to the system of an electron spin qubit that is confined in a quantum dot and driven by an in-plane electric field. We analyze how spin relaxation induced by the electrical noise due to electron-phonon interaction varies as a function of driving frequency, driving magnitude, driving field phase shift and spin-orbit coupling strengths.