Time evolution dynamics of three non-coupled two-level atoms independently interacting with their reservoirs is solved exactly by considering a damping Lorentzian spectral density.For three atoms initially prepared in...Time evolution dynamics of three non-coupled two-level atoms independently interacting with their reservoirs is solved exactly by considering a damping Lorentzian spectral density.For three atoms initially prepared in Greenberger-Horne-Zeilinger-type state,quantum correlation dynamics in a Markovian reservoir is compared with that in a nonMarkovian reservoir.By increasing detuning quantity in the non-Markovian reservoir,three-atom correlation dynamics measured by negative eigenvalue presents a trapping phenomenon which provides long-time quantum entanglement.Then we compare the correlation dynamics of three atoms with that of two atoms,measured by quantum entanglement and quantum discord for an initial robuster-entangled type state.The result further confirms that quantum discord is indeed different from quantum entanglement in identifying quantum correlation of many bodies.展开更多
A new high dynamic synchronization algorithm using cyclic spectral density was presented according to the theories of cyclic spectral density and its anti-interface and anti-noise properties.The closed forms of freque...A new high dynamic synchronization algorithm using cyclic spectral density was presented according to the theories of cyclic spectral density and its anti-interface and anti-noise properties.The closed forms of frequency error and phase error were obtained,and their performances were analyzed.The in-phase signal throw costas loop was normalized to obtain a cosine signal.Cyclic spectral density of the cosine signal of was computed to obtain the frequency error and the phase error and then results were put into NCO to synchronize.Finally,the performance of the presented algorithms was compared with the conventional algorithms by virtue of simulations,and the simulation results proved the correctness and the superiority of the new algorithms.展开更多
As a new partially coherent beam, the propagation properties of the multi-hyperbolic sine-correlated (MHSC) beams in turbulent atmospheres have been studied. But as another important medium, the propagation properties...As a new partially coherent beam, the propagation properties of the multi-hyperbolic sine-correlated (MHSC) beams in turbulent atmospheres have been studied. But as another important medium, the propagation properties of MHSC beams in oceanic turbulence. This paper has studied these questions in detail. The analytical formulas of spectral density and degree of coherence for the propagation are derived and the numerical simulations are represented. It is found that the intensity patterns of MHSC beams will evolve from dark-hollow profiles into Gaussian profiles caused by oceanic turbulence and will degenerate more rapidly with stronger oceanic turbulence. In addition, the coherence region becomes larger with decreasing in the dissipation rate of turbulence kinetic energy in unit mass liquid or increasing in the relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. We also find that the degree of coherence of MHSC beams with a higher-order N will decrease more slowly than those of hyperbolic sine-correlated (HSC) beams.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11104113 and 11264011)the Natural Science Foundation of Hunan Province,China (Grant Nos. 09JJ6011 and 11JJ6007)
文摘Time evolution dynamics of three non-coupled two-level atoms independently interacting with their reservoirs is solved exactly by considering a damping Lorentzian spectral density.For three atoms initially prepared in Greenberger-Horne-Zeilinger-type state,quantum correlation dynamics in a Markovian reservoir is compared with that in a nonMarkovian reservoir.By increasing detuning quantity in the non-Markovian reservoir,three-atom correlation dynamics measured by negative eigenvalue presents a trapping phenomenon which provides long-time quantum entanglement.Then we compare the correlation dynamics of three atoms with that of two atoms,measured by quantum entanglement and quantum discord for an initial robuster-entangled type state.The result further confirms that quantum discord is indeed different from quantum entanglement in identifying quantum correlation of many bodies.
基金Sponsored by the National Basic Research Program (Grant No. 2007CB310601)the High Technology Research and Development Program of China(Grant No. 2007AA12Z338)
文摘A new high dynamic synchronization algorithm using cyclic spectral density was presented according to the theories of cyclic spectral density and its anti-interface and anti-noise properties.The closed forms of frequency error and phase error were obtained,and their performances were analyzed.The in-phase signal throw costas loop was normalized to obtain a cosine signal.Cyclic spectral density of the cosine signal of was computed to obtain the frequency error and the phase error and then results were put into NCO to synchronize.Finally,the performance of the presented algorithms was compared with the conventional algorithms by virtue of simulations,and the simulation results proved the correctness and the superiority of the new algorithms.
文摘As a new partially coherent beam, the propagation properties of the multi-hyperbolic sine-correlated (MHSC) beams in turbulent atmospheres have been studied. But as another important medium, the propagation properties of MHSC beams in oceanic turbulence. This paper has studied these questions in detail. The analytical formulas of spectral density and degree of coherence for the propagation are derived and the numerical simulations are represented. It is found that the intensity patterns of MHSC beams will evolve from dark-hollow profiles into Gaussian profiles caused by oceanic turbulence and will degenerate more rapidly with stronger oceanic turbulence. In addition, the coherence region becomes larger with decreasing in the dissipation rate of turbulence kinetic energy in unit mass liquid or increasing in the relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. We also find that the degree of coherence of MHSC beams with a higher-order N will decrease more slowly than those of hyperbolic sine-correlated (HSC) beams.
