Evolution of l-photon excited thermo vacuum state in a single-mode damping channel

2016 ◽  
Vol 30 (05) ◽  
pp. 1650009
Author(s):  
Rui He ◽  
Hong-Yi Fan
Keyword(s):  
Laguerre Polynomial ◽  
Hermite Polynomials ◽  
Single Mode ◽  
Vacuum State ◽  
Summation Method ◽  
Squeezing Effect ◽  
Gaussian States ◽  
State Formula ◽  
Non Gaussian ◽  
Thermo Vacuum State

In this paper, we investigate how a kind of non-Gaussian states (l-photon excited thermo vacuum state [Formula: see text]) evolves in a single-mode damping channel. We find that it evolves into a Laguerre-polynomial-weighted real–fictitious squeezed thermo vacuum state, which exhibits strong decoherence and its original nonclassicality fades. In particular, when l = 0, in this damping process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic. In overcoming the difficulty of calculation, we employ the summation method within ordered product of operators, a new generating function formula about two-variable Hermite polynomials is derived.

Higher-order squeezing oscillations of the single-mode cavity field interacting with a three-level radiator

2017 ◽  
Vol 15 (08) ◽  
pp. 1740012
Author(s):  
V. I. Koroli ◽  
S. Palistrant ◽  
A. Nistreanu
Keyword(s):  
Exact Analytical Solution ◽  
Single Mode ◽  
Vacuum State ◽  
Higher Order ◽  
Initial Moment ◽  
Cavity Field ◽  
Two Photon ◽  
State Formula ◽  
Number Formula ◽  
Single Mode Cavity

We study the two-photon interaction between a three-level equidistant radiator (atom, molecule) with different dipole transitions and the single-mode cavity field. It is supposed that the three-level radiator is laser cooled and trapped into the ground vibrational state, in which the vibrational quantum number [Formula: see text]. In the proposed two-photon Jaynes–Cummings model (JCM) of a three-level atom at the initial moment [Formula: see text], the quantized cavity field is prepared in the squeezed vacuum state and the three-level radiator in the first excited state [Formula: see text]. By using the exact analytical solution for the state-vector of the coupled atom-field system, the amplitude-squared squeezing of the quantized cavity field is examined as a function of the [Formula: see text] and [Formula: see text] parameters. In this situation, higher-order squeezing has the tendency towards oscillations, but the exact periodicity of these oscillations is violated by the analogy with the second-order squeezing.

Linear bosonic quantum channels defined by superpositions

2018 ◽  
Vol 18 (5&6) ◽  
pp. 481-496
Author(s):  
T.J. Volkoff
Keyword(s):  
Optical Element ◽  
Single Mode ◽  
Coherent System ◽  
Closed Convex Hull ◽  
Quantum Channels ◽  
Quantum Superposition ◽  
Nonclassical State ◽  
Gaussian States ◽  
System 2 ◽  
Energy Quantum

A minimal energy quantum superposition of two maximally distinguishable, isoenergetic single mode Gaussian states is used to construct the system-environment representation of a class of linear bosonic quantum channels acting on a single bosonic mode. The quantum channels are further defined by unitary dynamics of the system and environment corresponding to either a passive linear optical element U_{BS} or two-mode squeezing U_{TM}. The notion of nonclassicality distance is used to show that the initial environment superposition state becomes maximally nonclassical as the constraint energy is increased. When the system is initially prepared in a coherent state, application of the quantum channel defined by U_{BS} results in a nonclassical state for all values of the environment energy constraint. We also discuss the following properties of the quantum channels: 1) the maximal noise that a coherent system can tolerate, beyond which the linear bosonic attenuator channel defined by U_{BS} cannot impart nonclassical correlations to the system, 2) the noise added to a coherent system by the phase-preserving linear amplification channel defined by U_{TM}, and 3) a generic lower bound for the trace norm contraction coefficient on the closed, convex hull of energy-constrained Gaussian states.

Teleportation improvement by noiseless linear amplification

2019 ◽  
Vol 19 (11&12) ◽  
pp. 935-951
Author(s):  
Hamza Adnane ◽  
Matteo G.A. Paris
Keyword(s):  
Coherent States ◽  
Large Range ◽  
Low Energy ◽  
Entangled State ◽  
Continuous Variables ◽  
Linear Amplification ◽  
Gaussian States ◽  
Linear Amplifier ◽  
Twin Beam ◽  
Non Gaussian

We address de-Gaussification of continuous variables Gaussian states by optimal non-deterministic noiseless linear amplifier (NLA) and analyze in details the properties of the amplified states. In particular, we investigate the entanglement content and the non-Gaussian character for the class of non-Gaussian entangled state obtained by using NL-amplification of two-mode squeezed vacua (twin-beam, TWB). We show that entanglement always increases, whereas improved EPR correlations are observed only when the input TWB has low energy. We then examine a Braunstein-Kimble-like protocol for the teleportation of coherent states, and compare the performances of TWB-based teleprotation with those obtained using NL-amplified resources. We show that teleportation fidelity and security may be improved for a large range of NLA parameters (gain and threshold).

Vehicle Risk Level Estimation by Using Experimental Trajectories in Bend

2011 ◽  
Author(s):  
Abdourahmane Koita ◽  
Dimitri Daucher ◽  
Michel Fogli
Keyword(s):  
Probability Density ◽  
Reliability Analysis ◽  
Probabilistic Models ◽  
Hermite Polynomials ◽  
Probabilistic Methods ◽  
Risk Level ◽  
General Context ◽  
Risk Levels ◽  
Modelling Uncertainties ◽  
Non Gaussian

This paper tackles the general context of road safety, focussing on the light vehicles safety in bends. It consists to use a reliability analysis in order to estimate the failure probability of vehicle trajectories. Firstly, we build probabilistic models able to describe measured trajectories in a given bend. The models are transforms of scalar normalized second order stochastic processes which are stationary, ergodic and non-Gaussian. The process is characterized by its probability density function and its power spectral density estimated starting from the experimental trajectories. The probability density is approximated by a development on the Hermite polynomials basis. The second part is devoted to apply a reliability strategy intended to associate a risk level to each class of trajectories. Based on the joint use of probabilistic methods for modelling uncertainties, reliability analysis for assessing risk levels and statistics for classifying the trajectories, this approach provides a realistic answer to the tackled problem.

Properties of two-mode squeezed Laguerre-polynomial-excited vacuum state generated by conditional measurement

2019 ◽  
Vol 94 (8) ◽  
pp. 085401
Author(s):  
Wei Ye ◽  
Liyun Hu ◽  
Kuizheng Zhang ◽  
Jiehui Huang ◽  
Zhiming Zhang
Keyword(s):  
Laguerre Polynomial ◽  
Vacuum State ◽  
Conditional Measurement
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