The effects of counter-rotating terms(CRTs)on Rabi splitting and the dynamic evolution of atomic population in the Jaynes–Cummings model are studied with a coherent-state approach.When the coupling strength increases...The effects of counter-rotating terms(CRTs)on Rabi splitting and the dynamic evolution of atomic population in the Jaynes–Cummings model are studied with a coherent-state approach.When the coupling strength increases,the Rabi splitting becomes of multi-Rabi frequencies for the initial state of an excited atom in a vacuum field,and the collapses and revivals gradually disappear,and then reappear with quite good periodicity.Without the rotating-wave approximation(RWA),the initial excited state contains many eigenstates rather than two eigenstates under the RWA,which results in the multi-peak emission spectrum.An analytical approximate solution for the strong coupling regime is obtained,which gives a new oscillation frequency and explains the recovery of collapses and revivals due to the equal energy spacing.展开更多
Quantum nonlocally correlated observables of the squeezed Bell-like states are investigated.We find that the higher amount of the entanglement does not always mean the stronger correlation of positions and momentums i...Quantum nonlocally correlated observables of the squeezed Bell-like states are investigated.We find that the higher amount of the entanglement does not always mean the stronger correlation of positions and momentums in the non-Gaussian states such as the photon-added states and the squeezed number states.Quantum nonlocal correlations of the amplitude-squared operators signal the entanglement existence of all the squeezed Bell-like states.展开更多
The spontaneous emission from a V-type three-level atom embedded in a two-band photonic crystal is studied.Due to the quantum interference between the two transitions and existence of two bands,the populations in the ...The spontaneous emission from a V-type three-level atom embedded in a two-band photonic crystal is studied.Due to the quantum interference between the two transitions and existence of two bands,the populations in the upper levels display some novel behavior:anti-trapping,population oscillation,and population inversion.展开更多
A new method to measure an atomic wave function is discussed.It effectively solves the problem of an initially random phase of a travelling-wave laser beam.The relationship between the measured data and the atomic wav...A new method to measure an atomic wave function is discussed.It effectively solves the problem of an initially random phase of a travelling-wave laser beam.The relationship between the measured data and the atomic wave function is presented,and the wave function's reconstruction procedure is also analyzed.展开更多
The properties of the spontaneous emission from a three-level atom with an external driving field in a photonic crystal are studied.The population in the two upper levels displays complete decay or oscillatory behavio...The properties of the spontaneous emission from a three-level atom with an external driving field in a photonic crystal are studied.The population in the two upper levels displays complete decay or oscillatory behavior,depending on the initial atomic state and the relative position of the two upper levels from the forbidden gap The intensity and the phase of the external field can also affect spontaneous emission from the atom.展开更多
We present the theoretical results on using the spontaneous emission which is induced from a two-level atom embedded in a photonic crystal with two bands and one forbidden gap.It is shown that the emission field from ...We present the theoretical results on using the spontaneous emission which is induced from a two-level atom embedded in a photonic crystal with two bands and one forbidden gap.It is shown that the emission field from the atom is composed of two parts,one is a localized field,which always exists,and the other is one or two propagating modes.The emission of the propagating mode depends on the gap size and the relative position of the upper-level of the atom with respect to the edges of the two bands.The propagating modes have a sudden jump from zero to a certain value when the gap or the related position of the upper level changes.This jump can be used to design an active optical two-channel or four-channel switch.Due to the localizedfield being within a few dozen atoms,the switch can be designed in a few micrometers.展开更多
The reconstruction of the atom-laser wave function is performed using interferometric measurement with a standing-wave grating,and the results in this scheme are studied.The relation between the measurement data and t...The reconstruction of the atom-laser wave function is performed using interferometric measurement with a standing-wave grating,and the results in this scheme are studied.The relation between the measurement data and the atomic wave function are also presented.This scheme is quite applicable and effectively avoids the initial random phase problem of the method that employs the laser running wave.The information which is encoded in the atom-laser wave is extracted.展开更多
A group of symmetric operators are introduced to carry out the separability criterion for bipartite and multipartite quantum states. All the symmetric operators, represented by a symmetric matrix with only two nonzero...A group of symmetric operators are introduced to carry out the separability criterion for bipartite and multipartite quantum states. All the symmetric operators, represented by a symmetric matrix with only two nonzero elements, and their arbitrary linear combinations are found to be entanglement witnesses. By using these symmetric operators, Wootters＇ separability criterion for two-qubit states can be generalized to bipartite and multipartite systems in arbitrary dimensions.展开更多
基金Supported by the National Basic Research Program of China(2011CB922203 and 2009CB929104)the National Natural Science Foundation of China(11174026,11174254 and 11104363)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China(20110191120046)the Fundamental Research Funds for the Central Universities under Grant(CQDXWL-2013-Z014).
文摘The effects of counter-rotating terms(CRTs)on Rabi splitting and the dynamic evolution of atomic population in the Jaynes–Cummings model are studied with a coherent-state approach.When the coupling strength increases,the Rabi splitting becomes of multi-Rabi frequencies for the initial state of an excited atom in a vacuum field,and the collapses and revivals gradually disappear,and then reappear with quite good periodicity.Without the rotating-wave approximation(RWA),the initial excited state contains many eigenstates rather than two eigenstates under the RWA,which results in the multi-peak emission spectrum.An analytical approximate solution for the strong coupling regime is obtained,which gives a new oscillation frequency and explains the recovery of collapses and revivals due to the equal energy spacing.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10774117 and 60778021.
文摘Quantum nonlocally correlated observables of the squeezed Bell-like states are investigated.We find that the higher amount of the entanglement does not always mean the stronger correlation of positions and momentums in the non-Gaussian states such as the photon-added states and the squeezed number states.Quantum nonlocal correlations of the amplitude-squared operators signal the entanglement existence of all the squeezed Bell-like states.
基金Supported in part by the National Natural Science Foundation of China under Grant No.19947005,Shanghai Education Commission Foundation and Faculty Research Grants from the Hong Kong Baptist University.
文摘The spontaneous emission from a V-type three-level atom embedded in a two-band photonic crystal is studied.Due to the quantum interference between the two transitions and existence of two bands,the populations in the upper levels display some novel behavior:anti-trapping,population oscillation,and population inversion.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19674048 and 29676037the Zhejiang Province Natural Science Foundation under Grant No.198023.
文摘A new method to measure an atomic wave function is discussed.It effectively solves the problem of an initially random phase of a travelling-wave laser beam.The relationship between the measured data and the atomic wave function is presented,and the wave function's reconstruction procedure is also analyzed.
基金Supported in part by the Shanghai Educational Council and FRG from Hong Kong Baptist University.
文摘The properties of the spontaneous emission from a three-level atom with an external driving field in a photonic crystal are studied.The population in the two upper levels displays complete decay or oscillatory behavior,depending on the initial atomic state and the relative position of the two upper levels from the forbidden gap The intensity and the phase of the external field can also affect spontaneous emission from the atom.
基金Supported by the Shanghai Research Center for Applied Physics.
文摘We present the theoretical results on using the spontaneous emission which is induced from a two-level atom embedded in a photonic crystal with two bands and one forbidden gap.It is shown that the emission field from the atom is composed of two parts,one is a localized field,which always exists,and the other is one or two propagating modes.The emission of the propagating mode depends on the gap size and the relative position of the upper-level of the atom with respect to the edges of the two bands.The propagating modes have a sudden jump from zero to a certain value when the gap or the related position of the upper level changes.This jump can be used to design an active optical two-channel or four-channel switch.Due to the localizedfield being within a few dozen atoms,the switch can be designed in a few micrometers.
基金Supported by the Hong Kong Baptist University Foundation(1997)the National Natural Science Foundation of China under Grant No.10074056+1 种基金the Zhejiang Natural Science Foundation under Grant Nos.198023 and 699025the“863”Foundation under Grant No.863-416-1-1-H11.
文摘The reconstruction of the atom-laser wave function is performed using interferometric measurement with a standing-wave grating,and the results in this scheme are studied.The relation between the measurement data and the atomic wave function are also presented.This scheme is quite applicable and effectively avoids the initial random phase problem of the method that employs the laser running wave.The information which is encoded in the atom-laser wave is extracted.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174118, 11364022 and 11174026, and the Natural Science Foundation of Jiangxi Province under Grant No 20114BAB212003.
文摘A group of symmetric operators are introduced to carry out the separability criterion for bipartite and multipartite quantum states. All the symmetric operators, represented by a symmetric matrix with only two nonzero elements, and their arbitrary linear combinations are found to be entanglement witnesses. By using these symmetric operators, Wootters＇ separability criterion for two-qubit states can be generalized to bipartite and multipartite systems in arbitrary dimensions.
