We develop a relativistic nuclear structure model, relativistic consistent angular-momentum projected shell-model (RECAPS), which combines the relativistic mean-field theory with the angular-momentum projection method...We develop a relativistic nuclear structure model, relativistic consistent angular-momentum projected shell-model (RECAPS), which combines the relativistic mean-field theory with the angular-momentum projection method. In this new model, nuclear ground-state properties are first calculated consistently using relativistic mean-field (RMF) theory. Then angular momentum projection method is used to project out states with good angular momentum from a few important configurations. By diagonalizing the hamiltonian, the energy levels and wave functions are obtained. This model is a new attempt for the understanding of nuclear structure of normal nuclei and for the prediction of nuclear properties of nuclei far from stability. In this paper, we will describe the treatment of the relativistic mean field. A computer code, RECAPS-RMF, is developed. It solves the relativistic mean field with axial-symmetric deformation in the spherical harmonic oscillator basis. Comparisons between our calculations and existing relativistic mean-field calculations are made to test the model. These include the ground-state properties of spherical nuclei <SUP>16</SUP>O and <SUP>208</SUP>Pb, the deformed nucleus <SUP>20</SUP>Ne. Good agreement is obtained.展开更多
Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a mu...Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a multiple-user detection（MUD） turbulence mitigation scheme in an OAM-multiplexed FSO communication link.First,we present a MUD equivalent communication model for an OAM-multiplexed FSO communication link under AT.In the equivalent model,each input bit stream represents one user＇s information.The deformed OAM spatial modes caused by AT,instead of the pure OAM spatial modes,are used as information carriers,and the overlapping between the deformed OAM spatial modes are computed as the correlation coefficients between the users.Then,we present a turbulence mitigation scheme based on MUD idea to enhance AT tolerance of the OAM-multiplexed FSO communication link.In the proposed scheme,the crosstalk caused by AT is used as a useful component to deduce users＇ information.The numerical results show that the performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme.When the turbulence strength C_n^2 is 1 × 10^（-15） m^（-2/3）,the transmission distance is 1000 m and the channel signal-to-noise ratio（SNR）is 26 dB,the bit-error-rate（BER） performance of four spatial multiplexed OAM modes l_m = ＋ 1,＋2,＋3,＋4 are all close to 10-5,and there is a 2-3 fold increase in the BER performance in comparison with those results without the proposed scheme.In addition,the proposed scheme is more effective for an OAM-multiplexed FSO communication link with a larger OAM mode topological charge interval.The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.展开更多
The relativistic consistent angular-momentum projected shell model(ReCAPS)is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus 52Fe.The model calculations sh...The relativistic consistent angular-momentum projected shell model(ReCAPS)is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus 52Fe.The model calculations show a reasonably good agreement with the data.The backbending at 12+is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.展开更多
A memory-based quantum repeater architecture provides a solution to distribute quantum information to an arbitrary long distance.Practical quantum repeaters are likely to be built in optical-fiber networks which take ...A memory-based quantum repeater architecture provides a solution to distribute quantum information to an arbitrary long distance.Practical quantum repeaters are likely to be built in optical-fiber networks which take advantage of the low-loss transmission between quantum memory nodes.Most quantum memory platforms have characteristic atomic transitions away from the telecommunication band.A nondegenerate photon pair source is therefore useful for connection of a quantum memory to optical fibers.Here,we report a high-brightness narrowband photon-pair source which is compatible with a rare-earth-ion-doped crystal Pr^3+:Y2SiO5.The photon-pair source is generated through a cavityenhanced spontaneous parametric down-conversion process with the signal photon at 606 nm and the idler photon at 1540 nm.Moreover,using the telecom C-band idler photons for heralding,we demonstrate the reversible transfer of orbital-angular-momentum qubit between the signal photon and the quantum memory based on Pr3^+:Y2SiO5.展开更多
基金The project supported in part by National Natural Science Foundation of China under Grant Nos.10047001,10347113+2 种基金the State Key Basic Research Development Program under Contract No.G200077400the Excellent Young Researcher Grant
文摘We develop a relativistic nuclear structure model, relativistic consistent angular-momentum projected shell-model (RECAPS), which combines the relativistic mean-field theory with the angular-momentum projection method. In this new model, nuclear ground-state properties are first calculated consistently using relativistic mean-field (RMF) theory. Then angular momentum projection method is used to project out states with good angular momentum from a few important configurations. By diagonalizing the hamiltonian, the energy levels and wave functions are obtained. This model is a new attempt for the understanding of nuclear structure of normal nuclei and for the prediction of nuclear properties of nuclei far from stability. In this paper, we will describe the treatment of the relativistic mean field. A computer code, RECAPS-RMF, is developed. It solves the relativistic mean field with axial-symmetric deformation in the spherical harmonic oscillator basis. Comparisons between our calculations and existing relativistic mean-field calculations are made to test the model. These include the ground-state properties of spherical nuclei <SUP>16</SUP>O and <SUP>208</SUP>Pb, the deformed nucleus <SUP>20</SUP>Ne. Good agreement is obtained.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61271238 and 61475075)the Open Research Fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology,Ministry of Education,China(Grant No.NYKL2015011)+1 种基金the Postgraduate Innovation Research Plan of Jiangsu Province,China(Grant No.CXZZ13_0489)the University Natural Science Foundation of Jiangsu Province,China(Grant No.16KJB510037)
文摘Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a multiple-user detection（MUD） turbulence mitigation scheme in an OAM-multiplexed FSO communication link.First,we present a MUD equivalent communication model for an OAM-multiplexed FSO communication link under AT.In the equivalent model,each input bit stream represents one user＇s information.The deformed OAM spatial modes caused by AT,instead of the pure OAM spatial modes,are used as information carriers,and the overlapping between the deformed OAM spatial modes are computed as the correlation coefficients between the users.Then,we present a turbulence mitigation scheme based on MUD idea to enhance AT tolerance of the OAM-multiplexed FSO communication link.In the proposed scheme,the crosstalk caused by AT is used as a useful component to deduce users＇ information.The numerical results show that the performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme.When the turbulence strength C_n^2 is 1 × 10^（-15） m^（-2/3）,the transmission distance is 1000 m and the channel signal-to-noise ratio（SNR）is 26 dB,the bit-error-rate（BER） performance of four spatial multiplexed OAM modes l_m = ＋ 1,＋2,＋3,＋4 are all close to 10-5,and there is a 2-3 fold increase in the BER performance in comparison with those results without the proposed scheme.In addition,the proposed scheme is more effective for an OAM-multiplexed FSO communication link with a larger OAM mode topological charge interval.The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.
基金Supported by the National Natural Science Foundation of China(Grant No.10805030)the Major State Basic Research Developing Program(Grant No.2007CB815005)
文摘The relativistic consistent angular-momentum projected shell model(ReCAPS)is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus 52Fe.The model calculations show a reasonably good agreement with the data.The backbending at 12+is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.
基金supported by the National Key R&D Program of China(2017YFA0304100)the National Natural Science Foundation of China(61327901,11774331,11774335,11504362,11821404,and 11654002)+2 种基金Anhui Initiative in Quantum Information Technologies(AHY020100)Key Research Program of Frontier Sciences,CAS(QYZDY-SSW-SLH003)the Fundamental Research Funds for the Central Universities(WK2470000023,WK2470000026)
文摘A memory-based quantum repeater architecture provides a solution to distribute quantum information to an arbitrary long distance.Practical quantum repeaters are likely to be built in optical-fiber networks which take advantage of the low-loss transmission between quantum memory nodes.Most quantum memory platforms have characteristic atomic transitions away from the telecommunication band.A nondegenerate photon pair source is therefore useful for connection of a quantum memory to optical fibers.Here,we report a high-brightness narrowband photon-pair source which is compatible with a rare-earth-ion-doped crystal Pr^3+:Y2SiO5.The photon-pair source is generated through a cavityenhanced spontaneous parametric down-conversion process with the signal photon at 606 nm and the idler photon at 1540 nm.Moreover,using the telecom C-band idler photons for heralding,we demonstrate the reversible transfer of orbital-angular-momentum qubit between the signal photon and the quantum memory based on Pr3^+:Y2SiO5.
