The entropy squeezing of an atom with a k-photon in the Jaynes Cummings model is investigated. For comparison, we also study the corresponding variance squeezing and atomic inversion. Analytical results show that entr...The entropy squeezing of an atom with a k-photon in the Jaynes Cummings model is investigated. For comparison, we also study the corresponding variance squeezing and atomic inversion. Analytical results show that entropy squeezing is preferable to variance squeezing for zero atomic inversion. Moreover, for initial conditions of the system the relation between squeezing and photon transition number is also discussed. This provides a theoretical approach to finding out the optimal entropy squeezing.展开更多
In this paper,the energy spectrum of the two-photon Jaynes-Cummings model（TPJCM） is calculated exactly in the non-rotating wave approximation（non-RWA）,and we study the level-crossing problem by means of fidelity.A...In this paper,the energy spectrum of the two-photon Jaynes-Cummings model（TPJCM） is calculated exactly in the non-rotating wave approximation（non-RWA）,and we study the level-crossing problem by means of fidelity.A narrow peak of the fidelity is observed at the level-crossing point,which does not appear at the avoided-crossing point.Therefore fidelity is perfectly suited for detecting the level-crossing point in the energy spectrum.展开更多
Authors investigate the model that two two level atoms interact with a single mode cavity. The formulation of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach...Authors investigate the model that two two level atoms interact with a single mode cavity. The formulation of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach. Besides, squeezing effect of the cavity field is studied and some novel features are obtained.展开更多
The model that two two level atoms interact with a singel mode cavity is studied. The exact solution of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach. Furt...The model that two two level atoms interact with a singel mode cavity is studied. The exact solution of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach. Furthermore, we investigate the dynamical properties of the photon statistics of the cavity field, and obtain a number of novel features.展开更多
Completely solving the dissipative dynamics of nonlinear Jaynes-Cumming model is a very difficult task.In our recent work (Phys. Lett. A284 (2001) 156), we just obtained analytical results of the field dissipative dyn...Completely solving the dissipative dynamics of nonlinear Jaynes-Cumming model is a very difficult task.In our recent work (Phys. Lett. A284 (2001) 156), we just obtained analytical results of the field dissipative dynamicsof the nonlinear JCM. In the present paper, employing the perturbative expansion of master equation, we obtain thedensity operator of the system (field +atom). The coherence losses of the system and of the atom are investigated whentwo-photon process is involved. We also study the effect of different atomic initial states and the influence of the fieldamplitude on the atomic coherence loss.展开更多
We propose a scheme for approximately and conditionally teleporting an unknown atomic-entangled statein dissipative cavity QED.It is the further development of the scheme of [Phys.Rev.A 69 (2004) 064302],where thecavi...We propose a scheme for approximately and conditionally teleporting an unknown atomic-entangled statein dissipative cavity QED.It is the further development of the scheme of [Phys.Rev.A 69 (2004) 064302],where thecavity mode decay has not been considered and the state teleportated is an unknown atomic state.In this paper,weinvestigate the influence of the decay on the approximate and conditional teleportation of the unknown atomic-entangledstate,which is different from that teleportated in [Phys.Rev.A 69 (2004) 064302] and then give the fidelity of theteleportation,which depends on the cavity mode decay.The scheme may be generalized to not only the teleportationof the cavity-mode-entangled-state by means of a singIe atom but also the teleportation of the unknown trapped-ion-entangled-state in a linear ion trap.展开更多
<正> In this paper,we find an analytic solution of the master equation of a non-resonant two-photon Jaynes-Cummings model(JCM)with phase damping with the help of the super-operator technique.We study the influen...<正> In this paper,we find an analytic solution of the master equation of a non-resonant two-photon Jaynes-Cummings model(JCM)with phase damping with the help of the super-operator technique.We study the influence ofphase damping on non-classical effects in the JCM,such as oscillations of the photon-number distribution,revivals of theatomic inversion,and sub-Possion photon statistics.It is demonstrated that the phase damping suppresses the revivalsof the atomic inversion and non-classical effects of the cavity field in the JCM.展开更多
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 ...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.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10674038 and 10604042)the National Basic Research Program of China (Grant No. 2006CB302901)
文摘The entropy squeezing of an atom with a k-photon in the Jaynes Cummings model is investigated. For comparison, we also study the corresponding variance squeezing and atomic inversion. Analytical results show that entropy squeezing is preferable to variance squeezing for zero atomic inversion. Moreover, for initial conditions of the system the relation between squeezing and photon transition number is also discussed. This provides a theoretical approach to finding out the optimal entropy squeezing.
基金Project supported by the National Natural Science Foundation of China (Grant No. 1097602/A06)
文摘In this paper,the energy spectrum of the two-photon Jaynes-Cummings model（TPJCM） is calculated exactly in the non-rotating wave approximation（non-RWA）,and we study the level-crossing problem by means of fidelity.A narrow peak of the fidelity is observed at the level-crossing point,which does not appear at the avoided-crossing point.Therefore fidelity is perfectly suited for detecting the level-crossing point in the energy spectrum.
文摘Authors investigate the model that two two level atoms interact with a single mode cavity. The formulation of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach. Besides, squeezing effect of the cavity field is studied and some novel features are obtained.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10474118 and 10274093, the National Fundamental Research Program of China under Grant No. 2005CB724502, and the Foundation from Educational Department of Sichuan Province of China under Grant No. 2004C017
文摘The model that two two level atoms interact with a singel mode cavity is studied. The exact solution of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach. Furthermore, we investigate the dynamical properties of the photon statistics of the cavity field, and obtain a number of novel features.
基金The project supported by National Natural Science Foundation of China under Grant No.10305002
文摘Completely solving the dissipative dynamics of nonlinear Jaynes-Cumming model is a very difficult task.In our recent work (Phys. Lett. A284 (2001) 156), we just obtained analytical results of the field dissipative dynamicsof the nonlinear JCM. In the present paper, employing the perturbative expansion of master equation, we obtain thedensity operator of the system (field +atom). The coherence losses of the system and of the atom are investigated whentwo-photon process is involved. We also study the effect of different atomic initial states and the influence of the fieldamplitude on the atomic coherence loss.
基金supported by the Beijing NSF under Grant No.1072010supported by Scientific Creative Platform Foundation of Beijing Municipal Commission of Education under Grant No.PXM2008_ 014224_067420
基金National Natural Science Foundation of China under Grant Nos.10774042 and 10474118the Natural Science Foundation of Hunan Province under Grant No.05J J0005the Science Research Fund of Educational Bureau of Hunan Province of China under Grant No.06C606
文摘We propose a scheme for approximately and conditionally teleporting an unknown atomic-entangled statein dissipative cavity QED.It is the further development of the scheme of [Phys.Rev.A 69 (2004) 064302],where thecavity mode decay has not been considered and the state teleportated is an unknown atomic state.In this paper,weinvestigate the influence of the decay on the approximate and conditional teleportation of the unknown atomic-entangledstate,which is different from that teleportated in [Phys.Rev.A 69 (2004) 064302] and then give the fidelity of theteleportation,which depends on the cavity mode decay.The scheme may be generalized to not only the teleportationof the cavity-mode-entangled-state by means of a singIe atom but also the teleportation of the unknown trapped-ion-entangled-state in a linear ion trap.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10274093, 10474118, and 10474120, the Natural Science Foundation of Hunan Province of China under Grant No. 05JJ3005, the Youth-Core Teachers Foundation of Hunan Province of China under Grant No. 2003165, and the Science Research Foundation of Educational Department of Hunan Province of China under Grant No. 05C756
文摘<正> In this paper,we find an analytic solution of the master equation of a non-resonant two-photon Jaynes-Cummings model(JCM)with phase damping with the help of the super-operator technique.We study the influence ofphase damping on non-classical effects in the JCM,such as oscillations of the photon-number distribution,revivals of theatomic inversion,and sub-Possion photon statistics.It is demonstrated that the phase damping suppresses the revivalsof the atomic inversion and non-classical effects of the cavity field in the JCM.
基金The project supported by the Natural Science Foundation of Education Department of Sichuan Province under Grant No. 2004A156 and the Scientific Research Foundation of CUIT under Grant No. CSRF200301, 200404
基金supported by the National Natural Science Foundation of China (Grant No. 10704031)the National Science Foundation for Fostering Talents in Basic Research of the National Natural Science Foundation of China (Grant No. J0630313)+1 种基金the Fundamental Research Fund for Physics and Mathematics of Lanzhou University (Grant No. Lzu05001)the Natural Science Foundation of Gansu Province, China (Grant No. 3ZS061-A25-035)
文摘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.
