Dynamics of decoherence in a noisy driven environment

TL;DR

This paper investigates how Gaussian noise affects the decoherence of a central spin coupled to a spin chain, revealing amplified decoherence at critical points, noise-dependent revivals, and altered non-Markovian behavior.

Contribution

It provides a detailed analysis of noise effects on decoherence dynamics in a driven environment, highlighting the scaling laws and the role of noise correlation time.

Findings

Decoherence is amplified at critical points by noise.

Revivals of decoherence decay exponentially with noise intensity.

Non-Markovianity decreases with noise but increases with noise correlation time.

Abstract

We analyze the decoherence dynamics of a central spin coupled to a spin chain with a time-dependent noisy magnetic field, focusing on how noise influences the system's decoherence. Our results show that decoherence due to the nonequilibrium critical dynamics of the environment is amplified in the presence of uncorrelated and correlated Gaussian noise. We demonstrate that decoherence factor consistently signals the critical points, and exhibits exponential scaling with the system size, the square of noise intensity, and the noise correlation time at the critical points. We find that strong coupling between the qubit and the environment leads to partial revivals of decoherence, which diminish with increasing noise intensity or decreasing noise correlation time. In contrast, weak coupling leads to monotonic enhanced decoherence. The numerical results illustrate that, the revivals decay and scale exponentially with noise intensity. Moreover, the revivals increase and indicate linear or power law scaling with noise correlation time depends on how the correlated noise is fast or slow. Additionally, we explore the non-Markovianity of the dynamics, finding that it decays in the presence of noise but increases as the noise correlation time grows.