The Quantum Properties Of Two Entangled Atoms Without Rotating Wave Approximation

Along with the development of the research on quantum optics, the research on the interaction between atom and field is widely concerned, We study the energy spectrum of Tavis-Cummings (T-C) model without rotating wave approximation and using displaced coherent state method get the exact solution, By using numerical calculation, the control variables, we study entanglement between the atoms and the light field state and the process of interaction in the binomial state light field while the T-C model in vacuum or coherent or binomial light field, and we discuss the influence of the atomic entanglement with the change of atomic initial state, the coupling strength of light field and the parameters of optical field, and some valuable conclusions are obtained. The result demonstrates that in the atom-cavity field system, the steady state energy spectrum in the model of atomic is determined, and didn’t change with the light field and atom in the exchange symmetry state, the ground state of the system is non-degenerate.In the system of atom with a vacuum field, the entanglement between two atoms always keeps maximal when the initial state is set to anti-symmetric, and the entanglement of the two atoms evolution strongly depends on the coupling strength and other parameters when the initial state is set to exchange-symmetry between two atoms, while the non-entangled initial state produce entanglement periodically due to the effect of non-rotating terms.In the system of atom with a coherent state light field, the coherent optical state light field, as an intermediate state, The change of average photon number can cause light field state by the vacuum state change to the classical field, so the average photon number make a contribution to the effect of the entanglement between the two atoms, and we can analysis that the change of coupling strength is stronger than other, such as the initial cavity field frequency, energy interval parameters, which can the influence on the system, especially when the coupling strength is large enough.In the system of atom with a binomial state light field, we can get the same conclusions, but while the initial state is non-entangled, the entanglement of the two atoms unlike above situations, But there is more stable and is much stronger than the entanglement in vacuum state and coherent state light field, we consider this is due to the characteristics of optical field of the coherent optical field.Through the comparison of the above, we can find that while two same particle interact with the optical field, there are similarities, such as the amplitude of entanglement in the process of interaction is not affected by the initial; Also have exceptions, such as the evolution of non-entangled initial state interacte with state binomial state light field which is completely inconsistent. but no matter it interacte with what kind of light field, the entangled are affected by the external parameters, namely, the entanglement between the atoms is extremely sensitive to the change of external parameter, this is we believe that entanglement is one of the reason of the most basic and most classic in quantum mechanics.