Decoherence and Relaxation of a Quantum Bit in the Presence of Rabi Oscillations

TL;DR

This paper investigates how strong driving fields and heat bath interactions affect the decoherence and relaxation of a quantum bit, deriving modified Bloch equations and analyzing experimental suppression of decoherence.

Contribution

It introduces generalized Bloch equations accounting for Rabi oscillations and demonstrates their relevance through analysis of a phase qubit coupled to a circuit.

Findings

Rabi oscillations modify qubit damping rates

Experimental evidence shows decoherence suppression in driven flux qubits

Generalized equations improve understanding of driven qubit dynamics

Abstract

Dissipative dynamics of a quantum bit driven by a strong resonant field and interacting with a heat bath is investigated. We derive generalized Bloch equations and find modifications of the qubit's damping rates caused by Rabi oscillations. Nonequilibrium decoherence of a phase qubit inductively coupled to a LC-circuit is considered as an illustration of the general results. It is argued that recent experimental results give a clear evidence of effective suppression of decoherence in a strongly driven flux qubit.