Entanglement Properties of Two-Mode Squeezed Coherent States in Radiation Field

Entanglement properties of two-mode squeezed coherent states in the radiation field are investigated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000) 2722]. The dependence of entanglement on squeeze angle and squeeze parameter is discussed. It shows that the system evolves into entangled states and entanglement does not increase persistently with the increase of squeeze angle and squeeze parameter. There only exists a certain squeeze angle in which the entanglement exists continuously.     

增光子奇偶相干态的相位特性

借助于Pegg-Barnett相位算符理论和数值计算方法,研究了增光子奇偶相干态的相位概率分布,在此基础之上,讨论了有关数算符和相位算符的压缩特性。结果表明,增光子奇偶相干态的相位概率分布与通常的奇偶相干态、非线性相干态不同,在这种新的奇偶相干态中,其Pegg-Barnett相位概率分布能明显地反映出不同的量子相位信息和干涉特性。同时发现,在参量α的某些不同的取值范围内,增光子奇偶相干态在数算符和相位算符分量上均存在压缩效应。     

New Even and Odd Nonlinear Coherent States and Their Nonclassical Properties

Based on Roy and Roy's work (Roy, B. and Roy, P. (2000). Journal of Optics B: Quantum Semiclass. Opt. 2, 65), a new type of even and odd nonlinear coherent states (NCSs) are defined. They result from Schrödinger cat states for deformed field. Using the numerical method, we study nonclassical properties of the new even and odd NCSs. It is shown that quantum statistical properties of the new even and odd NCSs are quite different from those of the usual even and odd coherent states (CSs). It is found that the squeezing only consists in the new even NCS, and the amplitude-squared squeezing and antibunching effect appear for both new even and odd NCSs in some ranges of ||.     

Even and Odd Coherent States for Time-Dependent Harmonic Oscillator

The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the classical equation of motion. In terms of this dynamical invariant we define the time-dependent creation and annihilation operators and relevantly introduce even and odd coherent states for time dependent harmonic oscillator. The mathematical and quantum statistical properties of these states are discussed in detail. The harmonic oscillator with periodically varying frequency is treated as a demonstration of our general approach.     

Even and Odd Coherent States for Time-Dependent Harmonic Oscillator

The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the classical equation of motion. In terms of this dynamical invariant we define the time-dependent creation and annihilation operators and relevantly introduce even and odd coherent states for time-dependent harmonic oscillator. The mathematical and quantum statistical properties of these states are discussed in detail. The harmonic oscillator with periodically varying frequency is treated as a demonstration of our general approach.     

Phase Properties of New Even and Odd Nonlinear Coherent States

Using the Pegg–Barnett formalism of phase operator, we obtain phase probability distributions of new even and odd nonlinear coherent states. It is shown that the distributions for the states are rather different, and unlike the case of ordinary even and odd coherent states the Pegg–Barnett distribution clearly reflects the different character of quantum interference in the case of the new even and odd coherent states.     

奇偶相干迭加态的振幅高次方压缩

本文引入了学子消灭算符四次方算符α＾４新的正交归一本征态：奇偶相干态和奇偶相干迭加态，并研究了奇偶相干迭加态的振幅高次方压缩特性。     

一种新的奇偶非线性相干态的位相统计性质

根据Pegg-Barnett位相定义, 计算了一种新的奇偶非线性相干态的位相概率分布函数, 利用数值计算方法研究了它们的位相统计性质. 数值计算结果表明：新的奇偶非线性相干态的位相特性与通常奇偶相干态的位相特性截然不同.     

Coordinate-Dependent Two-Mode Squeezing Transformations and the Corresponding Squeezed States

We introduce the coordinate-dependent two-mode squeezing transformations and discuss the properties of the corresponding two-mode squeezed states.     

Nonclassical Properties in Mesoscopic Josephson Junction with Excited Even and Odd Coherent States

Dynamic evolution of a mesoscopic Josephson junction (M J J) interacting with excited even and odd coherent states is studied. It is shown that the supercurrent in MJJ exhibits both collapse and revival (CR) phenomenon and squeezing effect. It is also shown that the CR and squeezing of supercurrent are related to degree of excitation and average photon number.     

Nonclassical Properties in Mesoscopic Josephson Junction with Excited Even and Odd Coherent States

Dynamic evolution of a mesoscopic Josephson junction (MJJ) interacting with excited even and odd coherent states is studied. It is shown that the supercurrent in MJJ exhibits both collapse and revival (CR) phenomenon and squeezing effect. It is also shown that the CR and squeezing of supercurrent are related to degree of excitation and average photon number.     

Properties of Amplitude N th-power Squeezing of Even and Odd qs-Coherent States

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A Class of Even and Odd Nonlinear Coherent States and Their Properties

A class of even and odd nonlinear coherent states are introduced. The properties of some related states, including quadrature squeezing, antibunching effect and phase probability distribution, are studied.     

A Class of Even and Odd Nonlinear Coherent States and Their Properties

A class of even and odd nonlinear coherent states are introduced. The properties of some related states, including quadrature squeezing, antibunching effect, and phase probability distribution, are studied.     

偶奇qs相干态的非经典特性

利用数值计算方法研究了ｑ和ｓ畸变对双参数形变偶奇ｑｓ相干态量子统计特性的委现偶奇ｑｓ相干态与通常的偶奇相干态有着显著不同的量子统计性质，压缩效应和反聚束效应均可在一定条件下的两种双参数畸变态中出现，偶奇ｑｓ相干态和通常偶奇相干态的差异随ｑ值偏离１越大和ｓ的取值越小而越大。     

Entanglement of Two-Mode Squeezed Even and Odd Coherent States

The two-mode squeezed even and odd coherent states are quantum states with some non-classical properties. The entanglement of two-mode squeezed even and odd coherent states are measured by non-classicality of P-function and separability inequalities of EPR-operators.     

Entanglement of Two-Mode Squeezed Even and Odd Coherent States

The two-mode squeezed even and odd coherent states are quantum states with some non-classical properties. The entanglement of two-mode squeezed even and odd coherent states are measured by non-classicality of P-function and separability inequalities of EPR-operators.     

Q变形非简谐振子广义奇偶相干态的高阶压缩特性

给出了Q变形的非简谐振子广义奇偶相干态的完备性证明,并且研究了它们的高阶压缩特性.结果表明,它们可组成一个完备的Hilbert空间,且均可呈现奇数阶压缩效应.     

奇偶对相干态的维格纳函数和层析图函数

利用纠缠态η〉表象下的维格纳算符,重构了奇偶对相干态的维格纳函数.根据维格纳函数在相空间中随变量ρ和γ的变化规律,讨论了奇偶对相干态的非经典性质和量子干涉效应.研究发现,奇偶对相干态总呈现非经典性质,并且当q取奇数时,奇偶对相干态更容易出现非经典性质.奇偶对相干态的量子干涉效应的显著程度与q取值有关,但对于q的同一取值,奇对相干态的量子干涉效应更为显著.利用纠缠态η〉表象下的维格纳算符Δ1,2(ρ,γ)和纠缠态η,τ1,τ2〉的投影算符之间满足的拉东变换,获得了奇偶对相干态的量子层析图函数.     

Coherent States and Squeezed States in Interacting Fock Space

In this paper we study coherent states and squeezed states in one mode interacting Fock space.