Negativity of the Wigner function as an indicator of non-classicality

Kenfack, Anatole; Życzkowski, Karol

doi:10.1088/1464-4266/6/10/003

Cited by 701 publications

(601 citation statements)

References 69 publications

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“…The negative Wigner function is a witness of the nonclassicality of a quantum state [30][31][32]. For a singlemode density operator ρ, the Wigner function in the coherent state representation |z can be expressed as…”

Section: Wigner Function and Parity Of The Generated Statementioning

confidence: 99%

Thermal state truncation by using quantum-scissors device

Zhao

Yuan

2017

Optics Communications

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A non-Gaussian state being a mixture of the vacuum and single-photon states can be generated by truncating a thermal state in a quantum scissors device of Pegg et al. [Phys. Rev. Lett. 81 (1998) 1604. In contrast to the thermal state, the generated state shows nonclassical property including the negativity of Wigner function. Besides, signal amplification and signal-to-noise ratio enhancement can be achieved.

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Section: Wigner Function and Parity Of The Generated Statementioning

confidence: 99%

Thermal state truncation by using quantum-scissors device

Zhao

Yuan

2017

Optics Communications

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“…Thus, if the initial fields are nonclassical, their degree of nonclassicality (as defined, e.g., in Refs. [44][45][46]) remains unchanged at any evolution times of the system. But yet we can observe SV and SR of entanglement and nonclassicality witnesses as will be shown in the following subsections.…”

Section: A Frequency Conversion Modelmentioning

confidence: 99%

Sudden vanishing and reappearance of nonclassical effects: General occurrence of finite-time decays and periodic vanishings of nonclassicality and entanglement witnesses

et al. 2011

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Analyses of phenomena exhibiting finite-time decay of quantum entanglement have recently attracted considerable attention. Such decay is often referred to as sudden vanishing (or sudden death) of entanglement, which can be followed by its sudden reappearance (or sudden rebirth). We analyze various finite-time decays (for dissipative systems) and analogous periodic vanishings (for unitary systems) of nonclassical correlations as described by violations of classical inequalities and the corresponding nonclassicality witnesses (or quantumness witnesses), which are not necessarily entanglement witnesses. We show that these sudden vanishings are universal phenomena and can be observed: (i) not only for two-or multi-mode but also for single-mode nonclassical fields, (ii) not solely for dissipative systems, and (iii) at evolution times which are usually different from those of sudden vanishings and reappearances of quantum entanglement.

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“…In this context, a thoroughly studied quantum system is the single-mode quantum harmonic oscillator interacting with a bosonic bath of oscillators. For such an open system, the decoherence time, ruling the transition from the quantum to the classical regime, may be identified by different nonclassicality criteria, which have been widely investigated [11][12][13][14][15][16][17][18][19][20][21][22][23][24] and compared [25]. Extensions to multimode systems [26][27][28][29] have been analyzed and the decoherence process has been addressed extensively [30,31].…”

Section: Introductionmentioning

confidence: 99%

Collapse and revival of quantum coherence for a harmonic oscillator interacting with a classical fluctuating environment

et al. 2015

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We address the dynamics of nonclassicality for a quantum system interacting with a noisy fluctuating environment described by a classical stochastic field. As a paradigmatic example, we consider a harmonic oscillator initially prepared in a maximally nonclassical state, e.g., a Fock number state or a Schrödinger-cat-like state, and then coupled to either a resonant or a nonresonant external field. Stochastic modeling allows us to describe the decoherence dynamics without resorting to approximated quantum master equations and to introduce non-Markovian effects in a controlled way. A detailed comparison among different nonclassicality criteria and a thorough analysis of the decoherence time reveal a rich phenomenology whose main features may be summarized as follows: (i) Classical memory effects increase the survival time of quantum coherence and (ii) a detuning between the natural frequency of the system and the central frequency of the classical field induces revivals of quantum coherence.

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Negativity of the Wigner function as an indicator of non-classicality

Abstract: A measure of nonclassicality of quantum states based on the volume of the negative part of the Wigner function is proposed. We analyze this quantity for Fock states, squeezed displaced Fock states and cat-like states defined as coherent superposition of two Gaussian wave packets.

Cited by 701 publications

References 69 publications

Thermal state truncation by using quantum-scissors device

Thermal state truncation by using quantum-scissors device

Sudden vanishing and reappearance of nonclassical effects: General occurrence of finite-time decays and periodic vanishings of nonclassicality and entanglement witnesses

Collapse and revival of quantum coherence for a harmonic oscillator interacting with a classical fluctuating environment

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