Entanglement versus Gaussian quantum discord in a double-cavity opto-mechanical system

Abstract

In this paper we investigate the robustness of the quantum correlations against the environment effects in various opto-mechanical bipartite systems. For two spatially separated opto-mechanical cavities, we give analytical formula for the global covariance matrix involving two mechanical modes and two optical modes. The logarithmic negativity as an indicator of the degree of entanglement and the Gaussian quantum discord which is a witness of quantumness of correlations are used as quantifiers to evaluate the different pairwise quantum correlations in the whole system. The evolution of the quantum correlations existing in this opto-mechanical system are analyzed in terms of the thermal bath temperature, squeezing parameter and the opto-mechanical cooperativity. We find that with desirable choice of these parameters, it is possible either enhance or annihilate the quantum correlations in the system. Various scenarios are discussed in detail. 1

Quantifying quantumness of correlations using Gaussian Rényi-2 entropy in optomechanical interfaces

“…These results can be explained by two types of quantum fluctuations transfer. The first one from the two-mode squeezed light to the optical subsystem, which corresponds to light-light quantum fluctuations transfer, and the second one from the two-mode squeezed light to the mechanical subsystem, which corresponds to light-matter quantum fluctuations transfer [32].…”

“…During the last few years, optomechanical devices based on the interaction between light and me-chanical degrees of freedom, have sparkled the interest of a vast scientific community as very promising platform for demonstrating various quantum phenomena [19]. Proposals include decoherence [20], quantum back-action evading [21], macroscopic quantum superposition [22], optomechanically induced transparency [23,24], the cooling of an harmonic oscillator near its quantum ground state [25,26,27], quantum states transfer [28], and also the study of various aspects of quantum correlations: quantum entanglement [29,30,31], quantum discord [32] and quantum steering [33].…”

Nonclassical correlations in a two-mode optomechanical system

“…In the systems of continuous-variables (CVs), the investigation of the entanglement properties has been the object of study in a number of recent publications in bipartite systems [13,27,28,29,30,31,32,33].…”

“…In this context, quantum optomechanical systems constitute a promising candidate to investigate quantum mechanical effects [20]. Proposals include the ground state optical cooling of the fundamental mechanical mode [21,22,23], the creation of macroscopic quantum superpositions or so-called Schrödinger's cat states [24], quantum state transfer [25], the detection of the gravitational waves [26], entangling states of mechanical modes to each other [13,27,28,29] or optical modes [30,31], the entanglement generation between two optical modes [32,33]. Now, it is more or less accepted that the encoding information in optomechanical systems can constitute a promising candidate in the field of quantum information science.…”

“…In this context, quantum optomechanical systems constitute a promising candidate to investigate quantum mechanical effects [20]. Proposals include the ground state optical cooling of the fundamental mechanical mode [21,22,23], the creation of macroscopic quantum superpositions or so-called Schrödinger's cat states [24], quantum state transfer [25], the detection of the gravitational waves [26], entangling states of mechanical modes to each other [13,27,28,29] or optical modes [30,31], the entanglement generation between two optical modes [32,33]. Now, it is more or less accepted that the encoding information in optomechanical systems can constitute a promising candidate in the field of quantum information science.We consider an optomechanical setup where a movable mirror is placed inside a Fabry-Perot cavity.The analysis of the entanglement in such tripartite optomechanical system, where a single mechanical mode is coupled to two optical cavities modes via radiation pressure, was studied in Ref [34], knowing that no further approximation has been done apart from the linearization around the classical steady…”