Coherent states of light

Ying Li

The distance functions Do(rj,rj')which is between two different multi-mode even coherent state light fields is obtained by using the concept of Ludwig Kn?芽ll's et.al.defined.Based on De(rj rj'),the separability of multi-mode even coherent sate light fields is analyzed by the multi-mode coherent state light fields these build up them.

Luca Salasnich

Fan An-fu

It is pointed out here that quantum phase properties, as well as dynamical properties, of light exhibit a sensitivity to the relative phase between the atomic dipole and light when the atom is prepared in a coherent superposition of its states in the two-level Jaynes-Cummings model interacting with a coherent state of light. The existence of the coherent-trapping of light is demonstrated by looking not only at the variance of the light phase about the coherent state value, and the number-phase uncertainty relation, but also at the factorization of the electric-field operator, and the photon-number distribution. We find also the factorization expression of the compound state of the atom-field system. We show once more that the phase properties of light based on the phase operator formalism of Pegg-Barnett and the coherence properties of light based on the coherence theory of Glauber are complementary in description of the optical quantum coherence.

Akira Furusawa

Ji‐Suo Wang

We have studied fidelity of two-level atom interacting with nonlinear coherent state light field by numerical calculation method.The variations of the fidelity with the parameter of light field,initial states of the atom and Lamb-Dicke parameter of the nonlinear coherent state are discussed respectively.It is shown that we can find light field state with larger average fidelity and smaller oscillation amplitude by selecting the appropriate parameters.If we regard light field as a quantum information carrier,to find high-fidelity nonlinear coherent states is to find a strong anti-interference ability quantum state which has great application value in quantum communication process.

Ulf Leonhardt