Gapped Quantum Criticality Gains Long Time Quantum Correlations

TL;DR

This paper demonstrates that gapped critical environments can significantly slow down decoherence and preserve quantum correlations, contrasting with gapless environments, and reveals new behaviors of quantum correlations near critical points.

Contribution

It uncovers how gapped critical environments affect decoherence and quantum correlations differently from gapless ones, providing new insights into environment-induced quantum effects.

Findings

Quantum correlations decay exponentially with the square of relaxation time.

Quantum correlations show a power-law singularity at the gap.

Decoherence collapse is not an indicator of quantum phase transition.

Abstract

We show gapped critical environment could remarkably prevent an enhanced decay of decoherence factor and quantum correlations at the critical point, which is nontrivially different from the ones in a gapless critical environment (Quan, et.al Phys. Rev. Lett. \textbf{96}, 140604 (2006)). The quantum correlations display very fast decaying to their local minimum at the critical point while maximum decaying occurs away from this point. In particular, our results imply that collapse of decoherence factor is not indicator of a quantum phase transition of environment as opposed to what happens in a gapless criticallity. In the week coupling regime, the relaxation time, at which the quantum correlations touch rapidly local minima, shows a power-law singularity as a function of gap. Furthermore, quantum correlations decay exponentially with second power of relaxation time. Our results are important for a better understanding and characterisation of gap critical environment and its ability as entanglers in open quantum systems.