Stochastic resonance phenomena in spin chains

TL;DR

This paper investigates stochastic resonance effects in quantum spin chains, analyzing how different noise types influence quantum correlations and entanglement, revealing thresholds and conditions for sustained quantum coherence.

Contribution

It extends the understanding of stochastic resonance in quantum spin systems by analyzing combined noise effects and clarifying the mechanisms behind entanglement behavior.

Findings

Quantum correlations appear only above a noise threshold with decay.

Pure dephasing prevents steady-state entanglement.

Entanglement can persist with both noise types if dephasing is moderate.

Abstract

We discuss stochastic resonance-like effects in the context of coupled quantum spin systems. We focus here on an information-theoretic approach and analyze the steady state quantum correlations (entanglement) as well as the global correlations in the system when subject to different forms of local decoherence. In the presence of decay, it has been shown that the system displays quantum correlations only when the noise strength is above a certain threshold. We extend this result to the case of a Heisenberg XYZ exchange interaction and revise and clarify the mechanisms underlying this behaviour. In the presence of pure dephasing, we show that the system always remains separable in the steady state. When both types of noise are present, we show that the system can still exhibit entanglement for long times, provided that the pure dephasing rate is not too large.