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

Laser Physics Letters

Thermal effect on the generated quantum correlation between two superconducting qubits

A-B A Mohamed

Published Jun 27, 2016• 9 citations
Publisher

Abstract

Abstract Quantum correlations in two superconducting (SC) qubits, placed in an SC-cavity and driven by noise fields, are investigated by using quantum discord (QD) and measurement-induced nonlocality with quantum entanglement (QE). It was found that the initial values of QD and measurement-induced non-locality (MIN) grow from zero-values to non-zero values. This growth of quantum correlations is due to the unitary qubits–field interaction. It is found that by increasing the coupling to the thermal environment, the generated correlations (of QD, MIN and QE) return to their zero-values and the phenomena of the sudden death and sudden birth only occur for QE. It is interesting to note that the state of two superconducting qubits has the quantum discord and quantum nonlocality without entanglement. The ability of the thermal field parameter for the disappearance of the generated correlations depend on the spontaneous emission parameter and vice versa.

DOI
10.1088/1612-2011/13/8/085202

Related papers

Non-classical correlations in the general state of two SC-qubit with a phase damping: non-local correlation and geometric discord

Abdel‐Baset A. Mohamed, H. A. Hessian

A system consists of two charged qubits are initially prepared in a maximum entangled Bell state and having no mutual interaction, where each qubit interacts independently with a superconducting transmission line resonator. An analytical solution of the time evolution of the final state of the system with the effect of a phase decoherence is found. In previous works, quantum correlations are only investigated in X-state for the models which are as our model. In this work, the analytical formulas of the geometric quantum discord (GQD) and measurement-induced non-locality (MIN) are introduced for a general state of two-qubit (non-X-state). Quantum correlations are studied via GQD and MIN with quantum entanglement (QE). It is found that a sudden disappearance only occurs for QE, while MIN and GQD still exist. Due to the increase in the amplitude of the coherent states, the intervals of the sudden disappearance of QE increase and MIN and GQD decrease. It is interesting to note that initial correlations can be lost and they reach their stationary correlations with the increase in the intrinsic decoherence. The stationary correlation of MIN can be destroyed, it reach zero value, when both the decoherence effect and detuning are present simultaneously. By starting with different types of Bell-like states, the stationary correlations as well as the time intervals of sudden disappearance have notable changes. It is possible to control the quantum correlations with certain parameter sets.

Journal of Modern Optics•Oct 27, 2016•6 citations

Stationary discord and non-local correlations via qubit damping

A.‐S. F. Obada, H. A. Hessian, A.‐B. A. Mohamed +1 more

By using quantum discord (QD), measurement induced non-locality (MIN) and negativity (QE), quantum correlation and entanglement are investigated for two qubits in two different cases for the initial two qubit Werner states, taking into account the influence of qubit damping. It is shown that there is no asymptotic decay for MIN while asymptotic decay exists for QD and QE. Quantum correlations cannot be strengthened by introducing the damping. The appearance time of stationary correlations gets shorter with the increase in the damping parameter. Finally, a uniform damping qubit can affect the stationary correlations when the qubits are initially in an entangled state.

Journal of Modern Optics•Mar 16, 2015•6 citations

Time evolution of quantum correlations in superconducting flux-qubits under classical noises

Tchoffo Martin, Arthur Tsamouo Tsokeng, Fouokeng Georges Collince +1 more

We analyze the dynamics of both entanglement and quantum discord (QD) in a system of two non-interacting flux-qubits initially prepared in a Bell's state and subjected to either static or random telegraph noises (RTNs). Both independent and common sources of system-environment coupling are considered either in the Markovian or non-Markovian regime and the results are compared to those of ordinary qubits. Under suitable conditions, both entanglement and QD are more robust in flux-qubit systems than classical ones. In the Markovian regime where the decay is monotonic, they are both stronger in different environment coupling than in common coupling, while the opposite is found in the non-Markovian regime where the dynamics is stressed by sudden death and revival phenomena, more robust in qubits than in flux-qubits under dynamical RTN. Weakness of revival amplitudes is interpreted as a noise spectrum-related induced interaction affecting quantum features of the system, while energy level non-degeneracy (at zero-splitting) of flux-qubits induces a phase factor that set conditions under which entangled states can be experimentally witnessed in flux-qubit systems. Note that the energy levels non-degeneracy has no particular effect on other entanglement measures apart from entanglement witnesses.

International Journal of Quantum Information•Feb 23, 2017•1 citation

EFFECTS OF CLASSICAL ENVIRONMENTAL NOISE ON ENTANGLEMENT AND QUANTUM DISCORD DYNAMICS

Claudia Benedetti, Fabrizio Buscemi, Paolo Bordone +1 more

We address the effect of classical noise on the dynamics of quantum correlations, entanglement and quantum discord (QD), of two non-interacting qubits initially prepared in a Bell state. The effect of noise is modeled by randomizing the single-qubit transition amplitudes. We address both static and dynamic environmental noise corresponding to interaction with separate and common baths in either Markovian and non-Markovian regimes. In the Markov regime, a monotone decay of the quantum correlations is found, whereas for non-Markovian noise sudden death and revival phenomena may occur, depending on the characteristics of the noise. Entanglement and QD show the same qualitative behavior for all kind of noises considered. On the other hand, we find that separate and common environments may play opposite roles in preserving quantum correlations, depending on the noise regime considered.

arXiv:1209.4201•International Journal of Quantum Information•Dec 1, 2012•72 citations

Non-locality Correlation in Two Driven Qubits Inside an Open Coherent Cavity: Trace Norm Distance and Maximum Bell Function

A.‐B. A. Mohamed, Hichem Eleuch, C. H. Raymond Ooi

We analytically investigate two separated qubits inside an open cavity field. The cavity is initially prepared in a superposition coherent state. The non-locality correlations [including trace norm measurement induced non-locality, maximal Bell-correlation, and concurrence entanglement] of the two qubits are explored. It is shown that, the generated non-locality correlations crucially depend on the decay and the initial coherence intensity of the cavity field. The enhancement of the initial coherence intensity and its superposition leads to increasing the generated non-locality correlations. The phenomena of sudden birth and death entanglement are found.

Scientific Reports•Dec 23, 2019•79 citations

Effects of static noise on the dynamics of quantum correlations for a system of three qubits

Lionel Tenemeza Kenfack, Tchoffo Martin, Fouokeng Georges Collince +1 more

Correlations in open quantum systems exhibit peculiar phenomena under the effect of various sources of noise. Here, we investigate the dynamics of entanglement and quantum discord (QD) for three noninteracting qubits coupled with a classical environmental static noise characterized by an external random field. Two initial entangled states of the system are examined, namely, the GHZ- and [Formula: see text]-type states. The system-environment interaction is here analyzed in three different configurations, namely, independent, mixed and common environments. We find that the dynamics of quantum correlations are strongly affected by the type of system-environment interaction and the purity of the initial entangled state. Indeed, depending on the type of interaction and the value of the purity of the initial state, peculiar phenomena such as sudden death, revivals and long-time survival of quantum correlations are observed. On the other hand, our results clearly show that quantum correlations initially present in the [Formula: see text]-type states are less robust than those of the GHZ-type states. Furthermore, we find that the long-time survival of entanglement can be detected by means of the suitable entanglement witnesses.

International Journal of Modern Physics B•Dec 13, 2016•14 citations
Abstract Quantum correlations in two superconducting (SC) qubits, placed in an SC-cavity and driven by noise fields, are investigated by using quantum discord (QD) and measurement-induced nonlocality with quantum entanglement (QE). It was found that the initial values of QD and measurement-induced non-locality (MIN) grow from zero-values to non-zero values. This growth of quantum correlations is due to the unitary qubits–field interaction. It is found that by increasing the coupling to the thermal environment, the generated correlations (of QD, MIN and QE) return to their zero-values and the phenomena of the sudden death and sudden birth only occur for QE. It is interesting to note that the state of two superconducting qubits has the quantum discord and quantum nonlocality without entanglement. The ability of the thermal field parameter for the disappearance of the generated correlations depend on the spontaneous emission parameter and vice versa.
A system consists of two charged qubits are initially prepared in a maximum entangled Bell state and having no mutual interaction, where each qubit interacts independently with a superconducting transmission line resonator. An analytical solution of the time evolution of the final state of the system with the effect of a phase decoherence is found. In previous works, quantum correlations are only investigated in X-state for the models which are as our model. In this work, the analytical formulas of the geometric quantum discord (GQD) and measurement-induced non-locality (MIN) are introduced for a general state of two-qubit (non-X-state). Quantum correlations are studied via GQD and MIN with quantum entanglement (QE). It is found that a sudden disappearance only occurs for QE, while MIN and GQD still exist. Due to the increase in the amplitude of the coherent states, the intervals of the sudden disappearance of QE increase and MIN and GQD decrease. It is interesting to note that initial correlations can be lost and they reach their stationary correlations with the increase in the intrinsic decoherence. The stationary correlation of MIN can be destroyed, it reach zero value, when both the decoherence effect and detuning are present simultaneously. By starting with different types of Bell-like states, the stationary correlations as well as the time intervals of sudden disappearance have notable changes. It is possible to control the quantum correlations with certain parameter sets.
By using quantum discord (QD), measurement induced non-locality (MIN) and negativity (QE), quantum correlation and entanglement are investigated for two qubits in two different cases for the initial two qubit Werner states, taking into account the influence of qubit damping. It is shown that there is no asymptotic decay for MIN while asymptotic decay exists for QD and QE. Quantum correlations cannot be strengthened by introducing the damping. The appearance time of stationary correlations gets shorter with the increase in the damping parameter. Finally, a uniform damping qubit can affect the stationary correlations when the qubits are initially in an entangled state.
We analyze the dynamics of both entanglement and quantum discord (QD) in a system of two non-interacting flux-qubits initially prepared in a Bell's state and subjected to either static or random telegraph noises (RTNs). Both independent and common sources of system-environment coupling are considered either in the Markovian or non-Markovian regime and the results are compared to those of ordinary qubits. Under suitable conditions, both entanglement and QD are more robust in flux-qubit systems than classical ones. In the Markovian regime where the decay is monotonic, they are both stronger in different environment coupling than in common coupling, while the opposite is found in the non-Markovian regime where the dynamics is stressed by sudden death and revival phenomena, more robust in qubits than in flux-qubits under dynamical RTN. Weakness of revival amplitudes is interpreted as a noise spectrum-related induced interaction affecting quantum features of the system, while energy level non-degeneracy (at zero-splitting) of flux-qubits induces a phase factor that set conditions under which entangled states can be experimentally witnessed in flux-qubit systems. Note that the energy levels non-degeneracy has no particular effect on other entanglement measures apart from entanglement witnesses.
We address the effect of classical noise on the dynamics of quantum correlations, entanglement and quantum discord (QD), of two non-interacting qubits initially prepared in a Bell state. The effect of noise is modeled by randomizing the single-qubit transition amplitudes. We address both static and dynamic environmental noise corresponding to interaction with separate and common baths in either Markovian and non-Markovian regimes. In the Markov regime, a monotone decay of the quantum correlations is found, whereas for non-Markovian noise sudden death and revival phenomena may occur, depending on the characteristics of the noise. Entanglement and QD show the same qualitative behavior for all kind of noises considered. On the other hand, we find that separate and common environments may play opposite roles in preserving quantum correlations, depending on the noise regime considered.
We analytically investigate two separated qubits inside an open cavity field. The cavity is initially prepared in a superposition coherent state. The non-locality correlations [including trace norm measurement induced non-locality, maximal Bell-correlation, and concurrence entanglement] of the two qubits are explored. It is shown that, the generated non-locality correlations crucially depend on the decay and the initial coherence intensity of the cavity field. The enhancement of the initial coherence intensity and its superposition leads to increasing the generated non-locality correlations. The phenomena of sudden birth and death entanglement are found.
Correlations in open quantum systems exhibit peculiar phenomena under the effect of various sources of noise. Here, we investigate the dynamics of entanglement and quantum discord (QD) for three noninteracting qubits coupled with a classical environmental static noise characterized by an external random field. Two initial entangled states of the system are examined, namely, the GHZ- and [Formula: see text]-type states. The system-environment interaction is here analyzed in three different configurations, namely, independent, mixed and common environments. We find that the dynamics of quantum correlations are strongly affected by the type of system-environment interaction and the purity of the initial entangled state. Indeed, depending on the type of interaction and the value of the purity of the initial state, peculiar phenomena such as sudden death, revivals and long-time survival of quantum correlations are observed. On the other hand, our results clearly show that quantum correlations initially present in the [Formula: see text]-type states are less robust than those of the GHZ-type states. Furthermore, we find that the long-time survival of entanglement can be detected by means of the suitable entanglement witnesses.