The transition from Quantum Zeno to anti-Zeno effects for a qubit in a cavity by modulating the cavity frequency

TL;DR

This paper demonstrates a method to switch between quantum Zeno and anti-Zeno effects in a qubit-cavity system by tuning the cavity frequency, without relying on the rotating wave approximation, revealing how decay rates depend on resonance conditions.

Contribution

It introduces a cavity frequency modulation strategy to observe QZE-AZE transition in a dressed state framework without using RWA, considering both intrinsic and cavity baths.

Findings

QZE occurs at cavity resonance with the qubit energy level spacing.

AZE appears when the cavity frequency is detuned from resonance.

Transition depends on coupling strength between qubit and cavity.

Abstract

We propose a strategy to demonstrate the transition from the quantum Zeno effect (QZE) to the anti-Zeno effect (AZE) by modulating the central frequency of the cavity mode. Our results are obtained without using the rotating wave approximation (RWA), and the initial state (a dressed state) is easy to prepare. When the central frequency of the cavity mode is resonant with the qubit energy level spacing, the normalized decay rate of the qubit is lower than 1, which manifests the QZE. However, when the cavity frequency is detuned from resonance, the normalized decay rate becomes larger than 1, which corresponds to the AZE. The change from the QZE to the AZE, by just varying the central frequency of the cavity mode, should allow to distinguish these two different effects. Moreover, we find that in the presence of both qubit's intrinsic bath and the cavity bath, the emergence of the QZE and the AZE behaviors relies not only on the match between the qubit energy level spacing and the central frequency of the cavity mode, but also on the coupling strength between the qubit and the cavity mode.