Quantum correlations of two-mode Gaussian systems in a thermal environment

Abstract

Abstract.In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of continuous variable quantum entanglement and quantum discord for a system consisting of two non-interacting nonresonant bosonic modes embedded in a thermal environment. We study the time evolution of logarithmic negativity, which characterizes the degree of entanglement, and show that in the case of an entangled initial squeezed thermal state, entanglement suppression takes place for all temperatures of the environment, including zero temperature. We analyze the time evolution of the Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and show that discord decays asymptotically in time under the effect of the thermal bath. We describe also the time evolution of classical correlations and quantum mutual information, which measures the total correlations of the quantum system.

Generation of Quantum Correlations in Bipartite Gaussian Open Quantum Systems

“…In Refs. [23][24][25][26][27][28] we described the time evolution of the entanglement for a system of two uncoupled bosonic modes interacting with a common environment. We take an initial two-mode squeezed thermal state, with the covariance matrix given by [29] …”

Quantum discord and its allies: a review of recent progress

“…As expected, the bang-bang pulse is shown to be useful to enhance the freezing time (related to what has been termed as 'freezing terminal' [293]) and thereby delays the sudden change in time. Quantum discord has also been calculated in various other prototypical models including spin-bosonic systems [735][736][737][738], detuned harmonic oscillators in a common heat bath [739], dissipative cascaded systems [740], qubits in a dissipative cavity [741], impurity qubits in BEC reservoir [742], continuous variable systems [743][744][745][746][747][748], etc.…”

“…Quantum discord has also been calculated in various other prototypical models including spin-bosonic systems [670][671][672][673], detuned harmonic oscillators in a common heat bath [674], dissipative cascaded systems [675], qubits in a dissipative cavity [676], impurity qubits in BEC reservoir [677], continuous variable systems [678][679][680][681][682][683], etc.…”

Coherence Dynamics of Two Interacting Bosonic Modes in a Thermal Environment

“…In order to obtain a realistic description of the quantum processes it is necessary to take decoherence and dissipation into consideration. Recently we studied, in the framework of the theory of open systems, the dynamics of quantum correlations of two, both uncoupled and coupled, bosonic modes embedded in a common thermal bath, for initial Gaussian states of the system [24][25][26][27][28][29][30]. e-mail: isar@theory.nipne.ro…”