The role of position momentum correlations in coherence freezing and purity behavior

TL;DR

This paper investigates how initial position-momentum correlations influence the coherence and purity of Gaussian quantum states, revealing an inverse relationship and a novel coherence freezing phenomenon driven by these correlations.

Contribution

It demonstrates the significant impact of initial position-momentum correlations on quantum coherence and purity dynamics, including the discovery of a correlation-driven coherence freezing effect.

Findings

Initial correlations cause opposing effects on coherence and purity.

Enhanced coherence can occur in more mixed states due to correlations.

A coherence freezing phenomenon is observed, independent of initial correlations.

Abstract

We explore the effects of Markovian bath coupling and initial position-momentum correlations on the coherence and purity of Gaussian quantum states. Our analysis focuses on the roles these factors play in the dynamics of quantum coherence, coherence lengths, and state purity. Our results reveal that initial position-momentum correlations have a remarkable impact on the quantum properties of the mixed state. These correlations lead to opposing behaviors in coherence and purity: as quantum coherence increases in response to stronger correlations, purity diminishes, and vice versa. This inverse relationship illustrates the phenomenon where, governed by these initial correlations, a state with greater mixing can display enhanced quantum coherence compared to a less mixed state. We also observe an unanticipated coherence freezing phenomenon, quantified by the relative entropy of coherence. Notably, this freezing is driven by initial position-momentum correlations, although the final frozen value is independent of these correlations.