Entanglement measure using Wigner function: Case of generalized vortex state formed by multiphoton subtraction

Banerji, Anindya; Singh, R. P.; Bandyopadhyay, Abir

doi:10.1016/j.optcom.2014.05.035

Cited by 29 publications

(13 citation statements)

References 42 publications

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“…The WF distribution 18 , 19 is a powerful appliance to explore the non-classicality via the positivity and negativity of the Wigner function. The negativity of WF is a sufficient but not necessary condition for non-classicality 20 – 23 . Phase space non-classicality can be visualized through the negative part of WF distribution, which cannot occur for classical light.…”

Section: Introductionmentioning

confidence: 99%

Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

Mohamed

Eleuch

2020

Sci Rep

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We explore the phase space quantum effects, quantum coherence and non-classicality, for two coupled identical qubits with intrinsic decoherence. the two qubits are in a nonlinear interaction with a quantum field via an intensity-dependent coupling. We investigate the non-classicality via the Wigner functions. We also study the phase space information and the quantum coherence via the Q-function, Wehrl density, and Wehrl entropy. It is found that the robustness of the non-classicality for the superposition of coherent states, is highly sensitive to the coupling constants. The phase space quantum information and the matter-light quantum coherence can be controlled by the two-qubit coupling, initial cavity-field and the intrinsic decoherence.

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Section: Introductionmentioning

confidence: 99%

Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

Mohamed

Eleuch

2020

Sci Rep

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“…In this section we study the effect of propagation through coupled waveguides on photon subtracted two mode squeezed vacuum states. It would be worthwhile to mention that these states also possess orbital angular momentum and their vortex nature is evident in the quadrature distributions [16,18]. It would also be interesting to study how the vortex structure is affected due to the propagation.…”

Section: A Photon Subtractionmentioning

confidence: 99%

Entanglement propagation of a quantum optical vortex state

Banerji

Singh

Banerjee

et al. 2016

Optics Communications

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We study the entanglement evolution of a quantum optical vortex state propagating through coupled lossless waveguides. We consider states generated by coupling two squeezed modes using a sequence of beam splitters and also by subtracting photons from the signal in spontaneous parametric down conversion. We reconstruct the Wigner function at a later time to study the correlation and quantify the entanglement after propagation using logarithmic negativity.

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“…The negative part of WF is a sufficient, but not necessary, condition for non-classicality of a quantum state; more precisely, a state with its WF being negative part is a non-classical state, whereas, for example, a squeezed state can be non-classical state with a non-negative WF. Therefore, the negative part of WF is used as an indicator for the non-classicality of a quantum state [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Coupling between Two Qubits in an Open Coherent Cavity: Nonclassical Information via Quasi-Probability Distributions

Mohamed

Eleuch

Obada

2019

Entropy

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In this paper, we investigate the dynamics of two coupled two-level systems (or qubits) that are resonantly interacting with a microwave cavity. We examine the effects of the intrinsic decoherence rate and the coupling between the two qubits on the non-classicality of different system partitions via quasi-probability functions. New definitions for the partial Q-function and its Wehrl entropy are used to investigate the information and the quantum coherence of the phase space. The amount of the quantum coherence and non-classicality can be appropriately tuned by suitably adopting the rates of the intrinsic-decoherence and the coupling between the two qubits. The intrinsic decoherence has a pronounced effect on the negativity and the positivity of the Wigner function. The coupling between the two qubits can control the negativity and positivity of the quasi-probability functions.The Q-function is one of the simplest QPDs in phase space, and it is always a positive distribution [19]. Q-function and its Wehrl entropy can be used to quantify the quantum correlations and phase space information [20,21]. The Q-function was studied only for representations of the cavity fields, two-level systems [19][20][21], and three-level systems [22,23].There are other information entropies, including von Neumann entropy [24], linear entropy, and Shannon information entropy [25], that are used as a measure for the entanglement in closed systems [10]. For open systems, they are used as a measure of the coherence loss, where there are two quantum coherence sources in a quantum system: The first is due to its unitary interaction, this coherence can be called entanglement between two subsystems and "coherence loss" for one of them. The second is in open systems, it leads to losing the quantum coherence. Wehrl entropy is an additional entropic quantity that has been successfully applied in measuring the entanglement. It gives quantitative and qualitative information on the entanglement of the bipartite system. It is a useful tool to investigate the dynamical properties that contain all the information about the system dynamics. It is proved that the Wehrl entropy exhibits a temporal evolution similar to the von Neumann entropy.Loss of coherence in open quantum systems is as familiar as decoherence [26,27]. An important type of decoherence in open quantum systems is that described by the intrinsic decoherence (ID) model, in which Milburn [28] considers that the system does not evolve continuously, where the quantum coherence is automatically destroyed as the system evolves. The Milburn model is only used to investigate analytically decoherence effects on the dynamics of the non-classicality of the QPDs in two qubits when they are interacting with a coherent cavity field [29]; however, the effect of the coupling constant between the two qubits is neglected.In the current work, (i) the physical model of two coupled two-level systems resonantly interacting with an open cavity initially in a superposition of coherent states is analytically des...

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Entanglement measure using Wigner function: Case of generalized vortex state formed by multiphoton subtraction

Cited by 29 publications

References 42 publications

Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

Entanglement propagation of a quantum optical vortex state

Influence of the Coupling between Two Qubits in an Open Coherent Cavity: Nonclassical Information via Quasi-Probability Distributions

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