The Mth Coherent State

In this article, we propose a new kind of quantum states based on acting the number operator M times \( {\hat{n}}^M \) on the coherent state. We term this state the Mth coherent state, based on the value of the power M. We find that it is strongly similar to the coherent state as the analysis of the photonic statistical distributions and the overlap with the coherent state illustrate. Also, we find that it asymptotically reaches the minimum uncertainty and has a localized behavior in the Husimi function. However, in contrast to coherent state, the Mth coherent state has strong nonclassical features such as antibunching and squeezing for a relatively long range. Other parameters and measurements are discussed and studied. Finally, we highlight the similarity between the higher orders of the near coherent states and the Mth coherent states in order to potentially generate our proposed state.

     

Mth Coherent State Induces Patterns in the Interaction of a Two-Level Atom in the Presence of Nonlinearities

International Journal of Theoretical Physics - Recently, the Mth coherent state (Mth CS) has been defined to be the resultant state of applying the number operator M times on the coherent state...     

The P-representation on Nonlinear Coherent State Basis

Using the technique of integration within an ordered product of nonlinear Bose operators and by composing the nonlinear coherent state's over-completeness relation, we construct the corresponding P-representation theory. The generalized P-representation for some nonlinear Bose operators can be established.     

Controlled Quantum Teleportation of Superposed Coherent State Using GHZ Entangled Coherent State

Controlled quantum teleportation of superposed coherent states using GHZ entangled 3-mode coherent states is studied. Proposed scheme can be implemented experimentally using linear optical components such as a symmetric lossless beam splitter, two phase-shifters and two photon counters. Fidelity is found close to unity for appreciable mean number of photons in coherent states and is 0.99 for mean photon number equal to two.

     

Photon-Added Entangled Coherent State

We propose a feasible scheme to create the single-mode or two-mode photon-added entangled coherent state (PAECS) and then compare its entanglement degree with that of the entangled coherent state or even the photon-added-and-subtracted entangled coherent state.     

q-Analogue Charged Coherent State and SU(3) Charged,Hypercharged Coherent State

We generahe the conception of q-analogue coherent state to the cases of charged coherent state and charged, hypercharged coherent state. Their explicit expressions in the ordinary Fock space are derived.     

Two-Parameter Deformed Spin Coherent State

A two-parameter deformed spin coherent state is construched, its completeness and normalized properties are studies. It is pointed out that the coherent property of he spin coherent states is affected by parameters q and s.     

Two-Mode Excited Entangled Coherent State: Nonclassicality and Entanglement

Two-mode excited entangled coherent states (TME-ECSs) are introduced by operating repeatedly the photon-excited operator on the ECSs. It is shown that the normalization constant is related to the product of two Laguerre polynomials. The influence of the operation on nonclassical behaviour of the ECSs is investigated in terms of cross-correlation function, anti-bunching effect and the negativity of Wigner function, which show that nonclassical properties can be enhanced. In addition, inseparability properties of the TME-ECSs are discussed by using Bell inequality and concurrence. It is found that the degree of quantum entanglement of even ECSs increases with the increase of the total excited photon number, and the violation of Bell inequality can be present for both even and odd case only when the total excited photon numbers are even and odd, respectively.     

New Integration Transformation Connecting Coherent State and Entangled State

With the help of technique of integration within an ordered product (IWOP) of operators we find new integration transformation connecting the coherent state and the biparticle entangled state. We also point out that under this kind of integration transformation the direct product of two single-variable Hermite polynomials behaves quite different from the two-variable Hermite polynomials, in this way we show that the latter is intrinsic to the phase space of quantum entanglement. As a byproduct, some operator identities for theoretical quantum optics can also be neatly expressed in terms of the two-variable Hermite polynomials.     

Multipartite Entanglement Transfer from Multi-Mode Coherent State to Spin Qubits

The multipartite entanglement transfer from continuous variable system to spin qubits is investigated. We select multi-mode coherent field as continuous variable field. It is found that the qubits can not gain tripartite entanglement for states of close to GHZ state from the multi-mode coherent field. Moreover, the ability of the qubits gain the tripartite entanglement for states close to W state and bipartite entanglement from the continuous variable system is depended on the phase of multi-mode coherent field.     

Decoy State Quantum Key Distribution with Odd Coherent State

We propose a decoy state quantum key distribution scheme with odd coherent state which follows sub-Poissonian distributed photon count and has low probability of the multi-photon event and vacuum event in each pulse. The numerical calculations show that our scheme can improve efficiently the key generation rate and secure communication distance. Fhrthermore, only one decoy state is necessary to approach to the perfect asymptotic limit with infinite decoy states in our scheme, but at least two decoy states are needed in other scheme.     

基于纠缠态表象和自旋相干态的新复变函数空间

本文利用有序算符内的积分(IWOP)技术,构造了一个基于单变量厄米多项式H2j(ξ*+τξ/2√τ)的新复变函数空间,该空间与纠缠态表象及施温格玻色环境下的自旋相干态有关。推导出了包含二元厄米多项式的二项式定理,有助于构造新的复变函数空间。同时还提出了一种新的基于H2j(ξ*+τξ/2√τ)的积分变换及其逆变换,这对于推导某些算符恒等式是很有用的。     

研究热相干态的Wigner函数

利用相干态表象下的Wigner算符和有序算符内的积分(IWOP)技术,首先得到了热相干态(量子纯态)的Wigner函数;同时借助相干态表象和算符的正规乘积形式给出了相应混合态的Wigner函数.结果表明,热相干态与相应混合态的Wigner甬数是相一致的,支持了热场动力学(TFD)理论.且采用相干态表象下的Wigner算符、IWOP技术和算符的正规乘积形式来研究量子态的Wigner函数非常简捷方便.研究结果加深了人们对量子统计中相空间技术和热场动力学(TFD)理论的认识,且对于其它量子纯态与相应混合态相空间分布函数一致性的研究具有很好的理论指导意义.     

Number-Conserving Coherent State in Rindler Space

We introduce a kind of number-conserving coherent state in Rindler space which can describe the quantum state of thermal particles observed in Rindler space. This is based on the Unruh effect that the thermal particles seen by an accelerating observer in fiat space can be seen by an inertial observer in curved space under a conformal transformation.     

Wigner Function of Thermo-Invariant Coherent State

By using the thermal Winger operator of thermo-field dynamics in the coherent thermal state ｜ξ｜ representation and the technique of integration within an ordered product of operators, the Wigner function of the thermoinvariant coherent state ｜z,η） is derived. .The nonclassical properties of state [zη] is discussed based on the negativity of the Wigner function.     

Single-Mode Excited GHZ-type Entangled Coherent State

A class of the single-mode excited GHZ-type entangled coherent states (EGHZECSs) are presented. we exhibit the remarkable properties of the single-mode EGHZECSs, depended on the excitation photon number, such as entanglement and nonlocality via investigating their concurrence of entanglement and examining their violation of CHSH inequality. Finally, we propose how to generate the EGHZECSs by using cavity QED and quantum measurement and by using BBO crystal and single-photon detection technique, respectively.     

Teleportation of a Coherent Superposition State Via a nonmaximally Entangled Coherent Xhannel

We investigate the problemm of teleportation of a superposition coherent state with nonmaximally entangled coherent channel. Two strategies are considered to complete the task. The first one uses entanglement concentration to purify the channel to a maximally entangled one. The second one teleports the state through the nonmaximally entangled coherent channel directly. We find that the probabilities of successful teleportations for the two strategies are depend on the amplitudes of the coherent states and the mean fidelity of teleportation using the first strategy is always less than that of the second strategy.     

Single-Step Traveling-Wave Quantum State Engineering in the Coherent State Representation

We describe a recently introduced single-step traveling-wave quantum state engineering scheme using the one-dimensional coherent-state representation introduced by Janszky. In this representation, the photon number expansion of the output state is derived in a compact formula that is advantageous for numerical optimization. Using this formula, we determine several sets of physically controllable parameters of the scheme yielding various nonclassical target states.     

Generalized Bargmann Representation of Spin Coherent State

Based on the conclusion that the generalized Bargmann representation of a two-mode Fock state is a two-variable Hermite polynomial function [Hong-Yi Fan and Jun-hua Chen, Phys. Lett. A303 (2002) 311] we derive the generalized Bargmann representation of the spin coherent state and some new relations in the generalized function space.     

Properties of Coherent State for Hydrogen Atom

We construct the coherent state for the two-dimensional hydrogen atom, for which the averaged motion ofposition describes a Kepler ellipse. The coherent state can be expanded with respect to the eigenstates of 2D hydrogenatom, from which we evaluate the binding energy of the wave packet for this state.