Bipartite quantum coherence in noninertial frames

TL;DR

This paper studies how quantum coherence in scalar and Dirac fields decreases with acceleration due to the Unruh effect, revealing differences in coherence degradation between the two fields and implications for relativistic quantum computation.

Contribution

It investigates the behavior of quantum coherence in noninertial frames for scalar and Dirac fields using the relative entropy measure, highlighting differences in coherence decay at high accelerations.

Findings

Quantum coherence decreases monotonically with increasing acceleration.

In the scalar field, coherence vanishes at infinite acceleration.

In the Dirac field, some coherence persists even at infinite acceleration.

Abstract

Quantum coherence as the fundamental characteristic of quantum physics, provides the valuable resource for quantum computation in exceeding the power of classical algorithms. The exploration of quantum coherence in relativistic systems is of significance from both the fundamental points of view and practical applications. We investigate the quantum coherence of two free modes of scalar and Dirac fields as detected by two relatively accelerated observers by resorting to the relative entropy of coherence. We show that the relative entropy of coherence monotonically decreases when acceleration goes up, as a consequence of the Unruh effect. Specifically, the initial states with parameters $\alpha=b$ and $\alpha=\sqrt{1-b^2}$ have the same initial relative entropy coherence at $a=0$ (with $a$ the acceleration), but degrade along two different trajectories. The relative entropy of coherence reaches vanishing value in the scalar field in the infinite acceleration limit, but non-vanishing value in the Dirac field. This suggests that in the Dirac field, the bipartite state possesses quantum coherence to some extent with the variation of the relative acceleration, and may lead to potential applications in quantum computation performed by observers in motion relatively.