Thermal Quantum Correlations in Two Gravitational Cat States

Abstract

We consider the effect of a thermal bath on quantum correlations induced by the gravitational interaction in the weak field limit between two massive cat states, called gravitational cat (gravcat) states. The main goal of this paper is to provide a good understanding of the effects of temperature and several parameters in the entanglement (measured by the concurrence) and quantum coherence (measured by the l1-norm that is defined from the minimal distance between the quantum state and the set of incoherent states) which are derived from the thermal quantum density operator. Our results show that the thermal concurrence and l1-norm can be significantly optimized by increasing the masses or decreasing the distance between them. We investigate and discuss the behavior of these quantities under temperature variations in different regimes, including some that are expected to be experimentally feasible in the future. In particular, we observe that thermal fluctuations raise non-entangled quantum correlations when entanglement suddenly drops.

Quantum dense coding with gravitational cat states

“…In this paper, we put forward a simple question that we believe has not been addressed in the literature on this particular issue: how is the dense coding with gravcat states under a thermal bath? Although the influence of temperature on the quantum correlations of gravcat states in closed and open systems has been studied recently [41,42], here we aim to examine the effect of various parameters on the quantum advantages of dense coding with these states and to provide an efficient strategy for reducing the destructive effects.…”