Rabi oscillations in a qubit coupled to a quantum two-level system

TL;DR

This paper investigates Rabi oscillations in a qubit coupled to a quantum two-level system, combining numerical analysis with intuitive models to understand complex dynamics and propose experimental characterization methods.

Contribution

It provides a systematic numerical study of a driven qubit coupled to a two-level system, validating simple models and revealing new phenomena relevant for quantum environment characterization.

Findings

Numerical results agree with simple Rabi oscillation models

Identification of new phenomena in qubit-two-level system interactions

Proposed experimental procedure for environment characterization

Abstract

We consider the problem of a qubit driven by a harmonically oscillating external field while it is coupled to a quantum two-level system. We perform a systematic numerical analysis of the problem by varying the relevant parameters. The numerical calculations agree with the predictions of a simple intuitive picture, namely one that takes into consideration the four-level energy spectrum, the simple principles of Rabi oscillations and the basic effects of decoherence. Furthermore, they reveal a number of other interesting phenomena. We provide explanations for the various features that we observe in the numerical calculations and discuss how they can be used in experiment. In particular, we suggest an experimental procedure to characterize an environment of two-level systems.