Zeno and anti-Zeno effects on Dephasing

TL;DR

This paper investigates how quantum Zeno and anti-Zeno effects influence pure dephasing in quantum systems, revealing complex behaviors and transitions depending on system size, environment interaction, and coupling strength.

Contribution

It provides an exact microscopic analysis of Zeno and anti-Zeno effects on dephasing, including multiple regime transitions and the impact of environment evolution beyond weak coupling.

Findings

Single two-level system exhibits different behavior from population decay case.

Multiple two-level systems show multiple Zeno-anti-Zeno transitions.

Strong system-environment coupling significantly alters the effects.

Abstract

Quantum Zeno and anti-Zeno effects on pure dephasing are studied using exactly solvable microscopic models. The crossover between these two opposite effects is investigated. The case of a single two-level system undergoing dephasing is already different from the previously studied population decay problem, even without taking into account any back action from the environment. For many two-level systems interacting with a common environment, multiple transitions between Zeno and anti-Zeno regimes are predicted. Finally, if the system-environment coupling strength is not weak, we show that the nontrivial evolution of the environment between measurements can considerably alter the quantum Zeno and anti-Zeno effects.