ACTA PHOTONICA SINICA
Periodic Quantum Echo of Moving and Entangled Two-atom via Light Field Intensity-dependent Coupling
刘小娟 LIU Xiao-juan, 周并举 ZHOU Bing-ju, 姜春蕾 JIANG Chun-lei, 彭朝晖 PENG Zhao-hui, 刘明伟 LIU Ming-wei
Abstract
In this paper,the Tavis-Cummings(TC) model is generalized to simultaneously consider atomic motions and fields via intensity dependent coupling.Evolution of the fidelity of quantum states of entangled two-atom with motion interacting with light field via intensity-dependence coupling is investigated by means of the full quantum theory.The effects on the evolution of the fidelity of quantum states from the initial entanglement factor of the two-atom and the average photon number n-and field-mode structure parameter p of the field are researched by numerical calculations.The formation rule of quantum echoes of two-atoms is analyzed,and its physical essence is revealed.The results show that period quantum echo of the two-atom is always produced in the case of field-mode structure parameter p=1,independent of light intensity n-and the initial entanglement factor of the two-atom.Bell-state atoms can produce quantum echo with 2π/p cycle on the conditions of strongly coherent field,via changing the p of from 1 to any value less than 800.When p≥800,no matter what value of takes,the light field is a vacuum field,weakly coherent field or strong coherent field,the fidelity of quantum states of the two-atom is always 1,that is the first class Bell state-atoms is in the fidelity state continuously.But when the initial entanglement factor of two-atom is 3π/4,no matter how both values of n-,p are,the fidelity of quantum states of the two-atom maintains 1,namely the two-atom is in the fidelity state of the second class Bell-state continuously.The conclusions show that the extension model has good properties of periodic quantum echoes of two-atom,and provides the theoretical parameters and physical carrier for high fidelity output of entangled two-atoms information and experimental implementation of quantum information processing in the noise environment.