Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1609.02355 · Journal of Physics B Atomic Molecular and Optical Physics

Influence of classic noise on entangled state formation in parametric systems

V. O. Martynov, Vyacheslav A. Mironov, Lev A. Smirnov

Published Feb 24, 2017• 3 citations
arXivHTMLPDF

Abstract

Abstract A study of ‘high temperature’ entangled states in a system of two parametrically coupled quantum oscillators placed into independent thermal baths is performed taking into account partially coherent parametric pump. Processes in an open system are considered based on the Heisenberg–Langevin formalism. We obtain a closed system of equations for the averaged quadratic correlation functions in quantum stochastic problem as a result of Markov processes approximation. On the basis of numerical calculations the dynamics of the logarithmic negativity, which is the measure of entanglement in the system, is investigated. It is shown that the partial coherence of the parametric pump makes the lifetime of the entangled states finite. The threshold characteristics of the formation and existence of these states are specified.

DOI
10.1088/1361-6455/aa62ef

Related papers

Formation of entangled states in nonequilibrium quantum systems with partial coherent pumping

V. O. Martynov, Vyacheslav A. Mironov, Lev A. Smirnov

The problem of generating the entangled states of two parametrically coupled quantum oscillators at finite temperatures is considered. For coherent pumping, an analytical expression describing the behavior of logarithmic negativity is obtained using the Heisenberg–Langevin formalism. The expression also describes the attaining of a long nonzero steady-state value of logarithmic negativity. It is shown numerically that pumping noise limits the lifetime of entanglement in the system.

Bulletin of the Russian Academy of Sciences Physics•Jan 1, 2017•1 citation

Influence of clasic noise on entangled state formation in nonequlibrium systems

V. O. Martynov, Vyacheslav A. Mironov, Lev A. Smirnov

Features of high-temperature entangled states formation have been studied in a system consisting of two parametrically coupled identical quantum harmonic oscillators, each of which is placed in a separate independent thermal bath, in the conditions of partially coherent pumping.

International Conference Laser Optics (ICLO)•Jun 1, 2016•0 citations

Formation of entangled states of light in an optical parametric oscillator with partially coherent pumping

V. O. Martynov, Vyacheslav A. Mironov, Lev A. Smirnov

The quantum dynamics of an optical parametric oscillator under conditions of partially coherent pumping is considered. It is shown that if the pumping amplitude strongly exceeds a threshold value, the average number of emitted photons coincides with the estimate of the classical approximation, but the quantum state of light turns out to be entangled. Even though pumping noises reduce the magnitude of this entanglement, quantum correlations are not completely eliminated.

Bulletin of the Russian Academy of Sciences Physics•Jan 1, 2018•0 citations

Quantum correlation in degenerate optical parametric oscillators with mutual injections

Kenta Takata, Alireza Marandi, Y. Yamamoto

We theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. The cavity mode in the optical coupling path between the two oscillator facets is explicitly considered. Stochastic equations for the oscillators and mutual injection path based on the positive $P$ representation are derived. The system of two gradually pumped oscillators with out-of-phase mutual injections is simulated, and its quantum state is investigated. When the incoherent loss of the oscillators other than the mutual injections is small, the squeezed quadratic amplitudes $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{p}$ in the oscillators are positively correlated near the oscillation threshold. It indicates finite quantum correlation, estimated via Gaussian quantum discord, and the entanglement between the intracavity subharmonic fields. When the loss in the injection path is low, each oscillator around the phase transition point forms macroscopic superposition even under a small pump noise. It suggests that the squeezed field stored in the low-loss injection path weakens the decoherence in the oscillators.

arXiv:1506.00135•Physical Review A•Oct 16, 2015•53 citations

Entanglement of formation in two-mode Gaussian systems in a thermal environment

Irina Dumitru, Аурелиан Исар

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous variable entanglement for a system consisting of two non-interacting bosonic modes embedded in a thermal environment. The calculated measure of entanglement is entanglement of formation. We describe the evolution of entanglement in terms of the covariance matrix for symmetric Gaussian input states. In the case of an entangled initial squeezed thermal state, entanglement suppression (entanglement sudden death) takes place, for all non-zero temperatures of the thermal bath. After that, the system remains for all times in a separable state. For a zero temperature of the thermal bath, the system remains entangled for all finite times, but in the limit of asymptotic large times the state becomes separable.

AIP conference proceedings•Jan 1, 2015•1 citation

Quantum correlations in two-mode Gaussian open quantum systems

Аурелиан Исар

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 non-resonant 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.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jun 10, 2013•0 citations
Abstract A study of ‘high temperature’ entangled states in a system of two parametrically coupled quantum oscillators placed into independent thermal baths is performed taking into account partially coherent parametric pump. Processes in an open system are considered based on the Heisenberg–Langevin formalism. We obtain a closed system of equations for the averaged quadratic correlation functions in quantum stochastic problem as a result of Markov processes approximation. On the basis of numerical calculations the dynamics of the logarithmic negativity, which is the measure of entanglement in the system, is investigated. It is shown that the partial coherence of the parametric pump makes the lifetime of the entangled states finite. The threshold characteristics of the formation and existence of these states are specified.
We theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. The cavity mode in the optical coupling path between the two oscillator facets is explicitly considered. Stochastic equations for the oscillators and mutual injection path based on the positive PPP representation are derived. The system of two gradually pumped oscillators with out-of-phase mutual injections is simulated, and its quantum state is investigated. When the incoherent loss of the oscillators other than the mutual injections is small, the squeezed quadratic amplitudes $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{p}$ in the oscillators are positively correlated near the oscillation threshold. It indicates finite quantum correlation, estimated via Gaussian quantum discord, and the entanglement between the intracavity subharmonic fields. When the loss in the injection path is low, each oscillator around the phase transition point forms macroscopic superposition even under a small pump noise. It suggests that the squeezed field stored in the low-loss injection path weakens the decoherence in the oscillators.
In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous variable entanglement for a system consisting of two non-interacting bosonic modes embedded in a thermal environment. The calculated measure of entanglement is entanglement of formation. We describe the evolution of entanglement in terms of the covariance matrix for symmetric Gaussian input states. In the case of an entangled initial squeezed thermal state, entanglement suppression (entanglement sudden death) takes place, for all non-zero temperatures of the thermal bath. After that, the system remains for all times in a separable state. For a zero temperature of the thermal bath, the system remains entangled for all finite times, but in the limit of asymptotic large times the state becomes separable.
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 non-resonant 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.