We investigate the Floquet spectrum and excitation properties of a two-ultracold-atom system with periodically driven interaction in a three-dimensional harmonic trap.The interaction between the atoms is changed by va...We investigate the Floquet spectrum and excitation properties of a two-ultracold-atom system with periodically driven interaction in a three-dimensional harmonic trap.The interaction between the atoms is changed by varying the s-wave scattering length in two ways,the cosine and the square-wave modulations.It is found that as the driving frequency increases,the Floquet spectrum exhibits two main features for both modulations,the accumulating and the spreading of the quasienergy levels,which further lead to different dynamical behaviors.The accumulation is associated with collective excitations and the persistent growth of the energy,while the spread indicates that the energy is bounded at all times.The initial scattering length,the driving frequency and amplitude can all significantly change the Floquet spectrum as well as the dynamics.However,the corresponding relation between them is valid universally.Finally,we propose a mechanism for selectively exciting the system to one specific state by using the avoided crossing of two quasienergy levels,which could guide preparation of a desired state in experiments.展开更多
This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED.The first stage of the scheme requires usual teleportation.In...This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED.The first stage of the scheme requires usual teleportation.In the second stage of the scheme,with the assistance of the preparer,the perfect copies of an unknown atomic entangled state can be produced.展开更多
In this paper, we investigate the effects of the spatial variation of driving-laser phase in a collective two-atom system on the intensity-intensity correlations of the resonant fluorescence. It is shown that the inte...In this paper, we investigate the effects of the spatial variation of driving-laser phase in a collective two-atom system on the intensity-intensity correlations of the resonant fluorescence. It is shown that the intensity-intensity correlations exhibit quite different characteristics for the different values of the spatial phase of the laser at the position of the two atoms in both cases of the weak and strong driving lasers. Our results suggest that the intensity-intensity correlations can serve as a probe of the spatial interference effect arising from the spatial variation of the laser phase.展开更多
The model of two two level atoms interact with a single mode cavity was investigated. The formulation of the time evolution operator for the two atom Jaynes Cummings model is pressented by the bare states approach. Be...The model of two two level atoms interact with a single mode cavity was investigated. The formulation of the time evolution operator for the two atom Jaynes Cummings model is pressented by the bare states approach. Besides, the time evolution of the two atom common population probabilities is studied, and some novel features are obtained.展开更多
Considering three two-level atoms initially in the W or Greenberger-Horne-Zeilinger(GHZ) state,one of the three atoms is put into an initially coherent light cavity and made to resonantly interact with the cavity.The ...Considering three two-level atoms initially in the W or Greenberger-Horne-Zeilinger(GHZ) state,one of the three atoms is put into an initially coherent light cavity and made to resonantly interact with the cavity.The twoatom entanglement evolution outside the cavity is investigated.The influences of state-selective measurement of the atom inside the cavity and strength of the light field on the two-atom entanglement evolution outside the cavity are discussed.The results obtained from the numerical method show that the two-atom entanglement outside the cavity is strengthened through state-selective measurement of the atom inside the cavity.In addition,the strength of the light field also influences the two-atom entanglement properties.展开更多
We first propose a scheme for preparing the genuine Yeo-Chua 4-qubit entangled state via cavity QED. Using the genuine Yeo-Chua atomic state, we further propose a cavity QED scheme for teleporting an arbitrary two-ato...We first propose a scheme for preparing the genuine Yeo-Chua 4-qubit entangled state via cavity QED. Using the genuine Yeo-Chua atomic state, we further propose a cavity QED scheme for teleporting an arbitrary two-atom state. In two schemes the large-detuning is chosen and the necessary time is designed to be much shorter than Rydberg-atom’s lifespan. Both schemes share the distinct advantage that cavity decay and atom decay can be neglected. As for the interaction manipulation, our preparation scheme is more feasible than a recent similar one. Compared with the Yeo and Chua’s scheme, our teleportation scheme has significantly reduced the measuring difficulty.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12004049)the Fund of State Key Laboratory of IPOC(BUPT)(Grant Nos.600119525 and 505019124).
文摘We investigate the Floquet spectrum and excitation properties of a two-ultracold-atom system with periodically driven interaction in a three-dimensional harmonic trap.The interaction between the atoms is changed by varying the s-wave scattering length in two ways,the cosine and the square-wave modulations.It is found that as the driving frequency increases,the Floquet spectrum exhibits two main features for both modulations,the accumulating and the spreading of the quasienergy levels,which further lead to different dynamical behaviors.The accumulation is associated with collective excitations and the persistent growth of the energy,while the spread indicates that the energy is bounded at all times.The initial scattering length,the driving frequency and amplitude can all significantly change the Floquet spectrum as well as the dynamics.However,the corresponding relation between them is valid universally.Finally,we propose a mechanism for selectively exciting the system to one specific state by using the avoided crossing of two quasienergy levels,which could guide preparation of a desired state in experiments.
基金Project supported by the National Natural Science Foundation of China （Grant No 60261002） and the Science Foundation of Yanbian University （Grant No 2005-20）.
文摘This paper proposes a scheme where one can realize quantum cloning of an unknown two-atom entangled state with assistance of a state preparer in cavity QED.The first stage of the scheme requires usual teleportation.In the second stage of the scheme,with the assistance of the preparer,the perfect copies of an unknown atomic entangled state can be produced.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10804035)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200805111014)
文摘In this paper, we investigate the effects of the spatial variation of driving-laser phase in a collective two-atom system on the intensity-intensity correlations of the resonant fluorescence. It is shown that the intensity-intensity correlations exhibit quite different characteristics for the different values of the spatial phase of the laser at the position of the two atoms in both cases of the weak and strong driving lasers. Our results suggest that the intensity-intensity correlations can serve as a probe of the spatial interference effect arising from the spatial variation of the laser phase.
基金SupportedbytheFoundationofAnhuiprovincialeducationalcommittee (No .2 0 0 1kj2 63 )
文摘The model of two two level atoms interact with a single mode cavity was investigated. The formulation of the time evolution operator for the two atom Jaynes Cummings model is pressented by the bare states approach. Besides, the time evolution of the two atom common population probabilities is studied, and some novel features are obtained.
基金supported by the Natural Science Foundation of Fujian Province,China (Grant No. 2008J0217)
文摘Considering three two-level atoms initially in the W or Greenberger-Horne-Zeilinger(GHZ) state,one of the three atoms is put into an initially coherent light cavity and made to resonantly interact with the cavity.The twoatom entanglement evolution outside the cavity is investigated.The influences of state-selective measurement of the atom inside the cavity and strength of the light field on the two-atom entanglement evolution outside the cavity are discussed.The results obtained from the numerical method show that the two-atom entanglement outside the cavity is strengthened through state-selective measurement of the atom inside the cavity.In addition,the strength of the light field also influences the two-atom entanglement properties.
基金supported by the program for New Century Excellent Talents at the University of China (Grant No. NCET-06-0554)the National Natural Science Foundation of China (Grant Nos. 10975001,60677001, 10747146 and 10874122)+3 种基金the Science and Technology Fund of Anhui Province for Outstanding Youth (Grant No. 06042087)the Talent Foundation of Higher Education of Anhui Province for Outstanding Youth(Grant No. 2009SQRZ018)the Science Research Foundation of Anhui University for Youth (Grant No. 2009QN017B)the Natural Science Foundation of Guangdong Province (Grant Nos. 06300345 and 7007806)
文摘We first propose a scheme for preparing the genuine Yeo-Chua 4-qubit entangled state via cavity QED. Using the genuine Yeo-Chua atomic state, we further propose a cavity QED scheme for teleporting an arbitrary two-atom state. In two schemes the large-detuning is chosen and the necessary time is designed to be much shorter than Rydberg-atom’s lifespan. Both schemes share the distinct advantage that cavity decay and atom decay can be neglected. As for the interaction manipulation, our preparation scheme is more feasible than a recent similar one. Compared with the Yeo and Chua’s scheme, our teleportation scheme has significantly reduced the measuring difficulty.
