Quantifying the decay of quantum properties in single-mode states

We investigate the loss of nonclassicality and non-Gaussianity of a single-mode state of the radiation field in contact with a thermal reservoir. The damped density matrix for a Fock-diagonal input is written using the Weyl expansion of the density operator. Analysis of the evolution of the quasiprobability densities reveals the existence of two successive characteristic times of the reservoir which are sufficient to assure the positivity of the Wigner function and, respectively, of the $P$ representation. We examine the time evolution of non-Gaussianity using three recently introduced distance-type measures. They are based on the Hilbert-Schmidt metric, the relative entropy, and the Bures metric. Specifically, for an $M$-photon-added thermal state, we obtain a compact analytic formula of the time-dependent density matrix that is used to evaluate and compare the three non-Gaussianity measures. We find a good consistency of these measures on the sets of damped states. The explicit damped quasiprobability densities are shown to support our general findings regarding the loss of negativities of Wigner and $P$ functions during decoherence. Finally, we point out that Gaussification of the attenuated field mode is accompanied by a nonmonotonic evolution of the von Neumann entropy of its state conditioned by the initial value of the mean photon number.Comment: Published version. Comments are welcom

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“…See also a more recent analysis in Ref. [58]. For some pure nonclassical input states, a number state in Ref.…”

Section: Gaussification and Entropy Productionmentioning

confidence: 99%

Gaussification through decoherence

2013

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“…Since the covariance xp is non-null if the Gaussian state exhibits squeezing (Souza et al, 2008), if one measures xp , from the above relation it is possible to infer the Gouy phase for a matter wave which can be described by an evolving coherent wave packet. For light waves this is a simple task as can be seen below.…”

Section: The Generalized Uncertainty Relation For Light Wavesmentioning

confidence: 99%

Gouy phase and matter waves

Paz

Nemes

Faria

2007

J. Phys.: Conf. Ser.

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Photon-added squeezed thermal states: Statistical properties and its decoherence in a photon-loss channel

Fan

2010

Optics Communications

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Using the normally ordered Gaussian form of displaced-squeezed thermal field characteristic of average photon numbern, we introduce the photon-added squeezed thermo state (PASTS) and investigate its statistical properties, such as Mandel's Q-parameter, number distribution (as a Legendre polynomial), the Wigner function. We then study its decoherence in a photon-loss channel in term of the negativity of WF by deriving the analytical expression of WF for PASTS. It is found that the WF with single photon-added is always partial negative for the arbitrary values ofn and the squeezing parameter r.

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Quantifying the decay of quantum properties in single-mode states

Cited by 5 publications

References 28 publications

Gaussification through decoherence

Gaussification through decoherence

Gouy phase and matter waves

Photon-added squeezed thermal states: Statistical properties and its decoherence in a photon-loss channel

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