arXiv:0907.3798 · Chinese Physics B

Entanglement dynamics of a moving multi-photon Jaynes—Cummings model in mixed states

Lei Tan, Yuqing Zhang, Zhong-Hua Zhu

Published Jul 1, 2011• 12 citations

Abstract

Using the algebraic dynamical method, the entanglement dynamics of an atom-field bipartite system in a mixed state is investigated. The atomic center-of-mass motion and the field-mode structure are also included in this system. We find that the values of the detuning and the average photon number are larger, the amplitude of the entanglement is smaller, but its period does not increase accordingly. Moreover, with the increase of the field-mode structure parameter and the transition photon number, the amplitude of the entanglement varies slightly while the oscillation becomes more and more fast. Interestingly, a damping evolution of the entanglement appears when both the detuning and the atomic motion are considered simultaneously.

DOI: 10.1088/1674-1056/20/7/070303

Related papers

Quantum entanglement of the coherent field interacting with the moving atom being in a mixed state

Hong Li

Using the negative entropy method,the quantum entanglement character of the system of the coherent optical field interacting with the moving atom is studied.The influences of the atomic initial state,the field-mode structure parameter,the average photon number of the coherent field,the detuning,and the transition photon number on the entanglement character of the system are discussed.The result shows that the value of the entanglement degree of the system appears regular evolution and entanglement sudden death phenomenon(ESD)when the atomic motion is considered.When the atomic initial state tends to pure state,the entanglement degree of the system is larger relatively.With the increase of the average photon number of the coherent field,the value of the entanglement degree of the system becomes small,but the period for the regular evolution is almost unchanged.With the increase of the transition photon number,the value of the entanglement degree of the system becomes larger,the period of the oscillation becomes shorter,meanwhile the oscillation of the system becomes faster and faster.With the detuning increasing,the entanglement becomes small.

Journal of Atomic and Molecular PhysicsJan 1, 20130 citations

Quantum entanglement of binomial optical field interacting with moving atom in mixed state

Hongxin Li

Using negative entropy method,the quantum entanglement characteristics of the system of binomial optical field interacting with moving atom were studied.The influences of the atomic initial state,field-mode structure parameter,maximum photon number of binomial field,coefficient of binomial field,transition photon number and detuning were discussed.The results show that the value of entanglement degree of the system appears regular evolution and entanglement sudden death(ESD) phenomenon when atomic motion was considered.The increasing of the field-mode structure parameter shortens the period of the entanglement and results in a slight decreasing of amplitude.The atomic initial state affects the entanglement degree of the system.When the atomic initial state tends to pure state,the entanglement degree of the system is larger relatively.With increase of the maximum photon number of binomial field,the value of the entanglement degree of system becomes small,but the period for regular evolution is almost unchanged.When the field is in the middle states,the entanglement degree is smaller relatively.With the increase of the transition photon number,the value of the entanglement degree of the system becomes larger,the period of the oscillation becomes shorter,meanwhile the oscillation of the system becomes faster and faster.With the detuning increasing,the entanglement becomes small.

Chinese Journal of Quantum ElectronicsJan 1, 20140 citations

Entanglement Dynamics of a Moving Two-level Atom in a Quantized Field

Jun Zhang

The entanglement dynamics of a two-level atom with center-of-mass motion in a single-mode quantized field is investigated.The behavior of the entropy changes of the subsystems,as well as the concurrence of the coupled atom-field system is explored.These results show that when the atom is initially prepared in ground state anti-correlation behavior occurs,but a positively correlated behavior appears gradually as the increasing of the probability of the atom initially in excited state.Also,the amplitude of the concurrence increases with the increasing of the probability of the atom initially in excited state.In addition,with increasing of the atomic center-of-mass motion,both the amplitudes of the partial entropy changes and the concurrence are reduced.

Shinjang dashösi ilmiy jurniliJan 1, 20100 citations

COLLAPSE AND REVIVAL OF ATOMIC ENTANGLEMENT IN AN INTENSITY DEPENDENT JAYNES–CUMMINGS INTERACTION

Papri Saha, A. S. Majumdar, Sudha Singh +1 more

The evolution of entanglement of a bipartite spin-1/2 system coupled to a micromaser cavity field in an intensity-dependent Jaynes–Cummings model is studied in this paper. The dynamical process of the entanglement is investigated for different cavity fields. We find that the interactions lead to a phenomenon of periodic entanglement and disentanglement between the qubits. Effects such as the growth of the magnitude of atomic entanglement with the increase of the cavity photon number, arising out of the intensity-dependent atom-cavity coupling lead to interesting dissimilarities from the case of entanglement generated by the standard Jaynes–Cummings interaction.

International Journal of Quantum InformationDec 1, 20109 citations

Dynamics of atom-field entanglement: Towards strong-coupling and non-Markovian regimes

Nick Cummings, B. L. Hu

We examine the dynamics of bipartite quantum entanglement between a two-level atom and the electromagnetic field. We begin with the Jaynes-Cummings model with a single field mode and examine in detail the exact time evolution of entanglement, including cases where the atomic state is initially mixed and the atomic transition is detuned from resonance. We then explore the effects of other nearby modes by calculating the exact time evolution of entanglement in more complex systems with two, three, and five field modes. For these cases we can obtain exact solutions which include the strong-coupling regime. Finally, we consider the entanglement of a two-level atom with the infinite collection of modes present in the intracavity field of a Fabre-Perot cavity. In contrast to the usual treatment of atom-field interactions with a continuum of modes using the Born-Markov approximation, our treatment in all cases describes the full non-Markovian dynamics of the atomic subsystem under general couplings. Only when an analytic expression for the infinite mode case is desired do we need to make a weak coupling assumption which at late times approximates Markovian dynamics.

arXiv:0708.2257Physical Review AMay 30, 200817 citations

Partial entropy change and entanglement in the mixed state for a Jaynes–Cummings model with Kerr medium

Yuqing Zhang, Lei Tan, Zhu Zhong-Hua +2 more

By using the algebraic dynamical approach, an atom-field bipartite system in mixed state is employed to investigate the partial entropy change and the entanglement in a cavity filled with Kerr medium. The effects of different nonlinear intensities are studied. One can find that the Kerr nonlinearity can reduce the fluctuation amplitudes of the partial entropy changes and the entanglement of the two subsystems, and also influence their periodic evolution. Meanwhile, increasing the Kerr nonlinear strength can convert the anti-correlated behaviour of the partial entropy change to the positively correlated behaviour. Furthermore, the entanglement greatly depends on the temperature. When the temperature or the nonlinear intensity increases to a certain value, the entanglement can be suppressed greatly.

Chinese Physics BFeb 1, 20102 citations