Some properties of the coherent state

Wang Jisuo, Sun Chang-yong

In this paper, we use the numerical method to study the influences of and deformations on the quantum statistical properties of even and odd qs-coherent states. It is shown that nonclassical properties of the even and odd qs-coherent states are very different from those of the usual even and odd coherent states. It is found that squeezing and antibunching effect appear for both even and odd qs-coherent states in some range of the parameters , and . The smaller the and are, the larger the difference between the even and odd qs-coherent states and the usual even and odd coherent states is.

Chuan-hua Dong

Alastair Brodlie

Abdlgader Mohamed

The study of coherent states (CS) for a quantum mechanical system has \nreceived a lot of attention. The definition, applications, generalizations of \nsuch states have been the subject of work by researchers. A common starting \npoint of all these approaches is the observation of properties of the original \nCS for the harmonic oscillator. It is well-known that they are described \nequivalently as (a) eigenstates of the usual annihilation operator, (b) from \na displacement operator acting on a fundamental state and (c) as minimum \nuncertainty states. What we observe in the different generalizations proposed \nis that the preceding definitions are no longer equivalent and only some of \nthe properties of the harmonic oscillator CS are preserved. \nIn this thesis we propose to study a new class of coherent states and \nits properties. We note that in one example our CS coincide with the ones \nproposed by Glauber where a set of three requirements for such states has \nbeen imposed. The set of our generalized coherent states remains invariant \nunder the corresponding time evolution and this property is called temporal \nstability. Secondly, there is no state which is orthogonal to all coherent states (the coherent states form a total set). The third property is that we \nget all coherent states by acting on one of these states [¿fiducial vector¿] with \noperators. They are highly non-classical states, in the sense that in general, \ntheir Bargmann functions have zeros which are related to negative regions of \ntheir Wigner functions. Examples of these coherent states with Bargmann \nfunction that involve the Gamma and also the Riemann ¿ functions are represented. \nThe zeros of these Bargmann functions and the paths of the zeros \nduring time evolution are also studied.

Jian‐Sheng Wang, Jie Feng, TK Liu +1 more

A new kind of even and odd nonlinear coherent states are defined. Using the numerical method, we have studied quantum statistical properties of the new even and odd nonlinear coherent states. It is shown that quantum statistical properties of the new even and odd nonlinear coherent states are very different from those of the usual even and odd coherent states. It is found that, in some ranges of 1beta1, the squeezing only exists in the new even nonlinear coherent state, and the amplitude-squared squeezing and antibunching effect appear for both new even and odd nonlinear coherent states.

V. Bargmann, P. Butera, L. Girardello +1 more