Dynamics of a driven spin coupled to an antiferromagnetic spin bath

TL;DR

This paper investigates how a driven qubit's Rabi oscillations are affected by an antiferromagnetic spin bath, revealing dependencies on detuning, coupling, and environmental factors, with implications for decoherence and pointer states.

Contribution

It provides a detailed analysis of the decoherence dynamics of a driven central spin coupled to an antiferromagnetic bath, highlighting the effects of detuning and environmental parameters on Rabi oscillations.

Findings

Rabi oscillations exhibit collapses and revivals with detuning.

Eigenstates of the qubit act as pointer states in weak coupling.

Decoherence depends on bath temperature, structure, and coupling strength.

Abstract

We study the behavior of the Rabi oscillations of a driven central spin (qubit) coupled to an antiferromagnetic spin bath (environment). It is found that the decoherence behavior of the central spin depends on the detuning, driving strength, the qubit-bath coupling and an important factor, associated with the number of the coupled atoms, the detailed lattice structure, and the temperature of the environment. If the detuning exists, the Rabi oscillations may show the behavior of collapses and revivals; however, if the detuning is zero, such a behavior will not appear. We investigate the weighted frequency distribution of the time evolution of the central spin inversion and give this phenomenon of collapses and revivals a reasonable explanation. We also discuss the decoherence and the pointer states of the qubit from the perspectives of the von Neumann entropy. It is found that the eigenstates of the qubit self-Hamiltonian emerge as the pointer states in the weak system-environment coupling limit.