Quantum State Evolution Process Fidelity Problems

Quantum information is an advanced research topic in modern science and technology. The fresh subject devotes to exploit the fundamental principle of quantum mechanics and the wonderful characteristic of quantum state,such as quantum entanglement, squeezing,superposition etc,to perform the processing,study the fidelity of computation and transmission of information is unabsent.In this paper,cavity QED as an investigation subject,based on the research foundation of Jaynes—Cummings(JC)Model,the fidelity are studied via completely quantum theory. Firstly,we introduce the background and progress of quantum information.Secondly,we summarize the definition of entangled state fdelity.Thirdly,we discuss state evolution of Jaynes—Cummings models and introduce several Jaynes-Cummings models widely spread out.Lastly,the fidelities quantum states system in two-mode squeezing vacuum state Tavis-Cummings model has being considered.I have studied the system useing the full quantum theory.The dipole-dipole interaction of the two atoms have been considered.By considering the interaction between the two-mode squeezing vacuum state field and the environment(atoms),we investigate the quantum information fidelities of the atoms the field and the system in two-mode squeezing vacuum state Tavis-Cummings model.With the help of the computer's simulation,we get the system the atoms and the field's figures of proceeding evolution by time.finally.Analyze the changes of the above three when change the squeezing index r the dipole-dipole interaction constant g_a and the phaseφ.The result of our discussion indicates that r and k are important to the fidelity of the quantum information of the above three.When the two atoms are initially in the groud state,decrease r can increase the three fidelities.On the contrary,when the two atoms are initially in one of the Bell states,increase r can increase the three fidelites.