Relativistic motion on Gaussian quantum steering for two-mode localized Gaussian states

Realistic quantum systems always exhibit gravitational and relativistic features. In this paper, we investigate the properties of Gaussian steering and its asymmetry by the localized two-mode Gaussian quantum states, instead of the traditional single-mode approximation method in the relativistic setting. We find that the one-side Gaussian quantum steering will monotonically decrease with increasing observers of acceleration. Meanwhile, our results also reveal the interesting behavior of the Gaussian steering asymmetry, which increases for a specific range of accelerated parameter and then gradually approaches to a finite value. Such findings is well consistent and explained by the well-known Unruh effect, which could significantly destroy the one-side Gaussian quantum steering. Finally, our results could also be applied to the dynamical studies of Gaussian steering between the Earth and satellites, since the effects of acceleration is equal to the effects of gravity according to the equivalence principle.

Chaos Synchronization in Time-Dependent Duplex Networks

Though the complete chaos synchronization on single-layer networks has been well understood, it is still a challenge on multiplex networks. In this work, we study the complete chaos synchronization on time-dependent duplex networks in which interaction pattern among oscillators alternates periodically between two single-layer networks. The alternations between two layers are characterized by the offset strength A and the switching frequency ω. We find that there are two dynamical regimes depending on ω. For high ω, the critical A for the stable complete synchronization is independent of ω and the fast-switching approximation suggests that the time-dependent duplex networks can be approximated by the time-independent duplex networks with effective coupling strength. For low ω, the critical A depends on ω nonmonotonically. At extremely low ω, the estimation of the critical A can be obtained by a single-mode approximation taking one dominant transversal network mode to complete synchronization into considerations.

An investigation of some quantum correlations of Dirac fields in noninertial frames

In this paper, some concepts of quantum correlations, such as one-way quantum deficit, purity, and entanglement of formation are investigated between the modes of Dirac fields in noninertial frames. We consider two bipartite divisions of a tripartite system constructed by initial Werner states, which is shared between two relatively accelerated observers. The degradation of these quantum correlations is shown when the acceleration parameter increases. However, a nonzero amount of correlations survives even at infinite acceleration limit. Furthermore, we study the inevitable influence of mixedness factor of initial state on the quantum correlations behaviour. Finally, we review our calculation beyond single-mode approximation and point out some differences and similarities between the two regimes.

Quantum coherence of cosmological perturbations

In this paper, the degrees of quantum coherence of cosmological perturbations of different spins are computed in the large-scale limit and compared with the standard results holding for a single mode of the electromagnetic field in an optical cavity. The degree of second-order coherence of curvature inhomogeneities (and, more generally, of the scalar modes of the geometry) reproduces faithfully the optical limit. For the vector and tensor fluctuations, the numerical values of the normalized degrees of second-order coherence in the zero time-delay limit are always larger than unity (which is the Poisson benchmark value) but differ from the corresponding expressions obtainable in the framework of the single-mode approximation. General lessons are drawn on the quantum coherence of large-scale cosmological fluctuations.