Starting from famous Schrodinger equation within the framework of semi-c/assicai theory of light-matter interaction, we firstly obtain the anaiytical non-resonant solutions of the driven bipartite system＇s entangleme...Starting from famous Schrodinger equation within the framework of semi-c/assicai theory of light-matter interaction, we firstly obtain the anaiytical non-resonant solutions of the driven bipartite system＇s entanglement dynamics in independent and coherent double pathways. Numerical simulations show that under non-resonant condition, entanglement sudden death and revival between these transition patterns behave quite differently, indicating the utmost importance of transition pathways＇ interference. Furthermore, the laser pulse＇s area and detuning exert significant but quite distinct influences on the entanglement dynamics. Our analyses are helpful in manipulating entanglement in current experimental technology.展开更多
The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by util...The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.展开更多
We extend an optimal entanglement distillation of the triplet Greenberger–Horne–Zeilinger(GHZ) state via entanglement concentrating in the three-partite partially electron-spin-entangled systems. Two entanglement co...We extend an optimal entanglement distillation of the triplet Greenberger–Horne–Zeilinger(GHZ) state via entanglement concentrating in the three-partite partially electron-spin-entangled systems. Two entanglement concentration protocols are similarly designed in detail with the post-selection in quantum-dot(QD) and micro-cavity coupled systems. The proposed protocol can be repeated several rounds to achieve an optimal success probability with an assistance of the ancillary QD, where only the single photon needs to pass through the micro-cavity for each round. It increases the total success probability of the distillation even if the implemented cavity is imperfect in practice during the whole process.展开更多
基金Supported by the National Basic Research Program(973 Program)of China under Grant No.2012CB921900the National Natural Science Foundation of China under Grant No.10574166the Guangdong Natural Science Foundation under Grant No.8151027501000062
文摘Starting from famous Schrodinger equation within the framework of semi-c/assicai theory of light-matter interaction, we firstly obtain the anaiytical non-resonant solutions of the driven bipartite system＇s entanglement dynamics in independent and coherent double pathways. Numerical simulations show that under non-resonant condition, entanglement sudden death and revival between these transition patterns behave quite differently, indicating the utmost importance of transition pathways＇ interference. Furthermore, the laser pulse＇s area and detuning exert significant but quite distinct influences on the entanglement dynamics. Our analyses are helpful in manipulating entanglement in current experimental technology.
基金the Natural Science Foundation of Shaanxi Province of China (Grant No 2001SL04)the Science and Technology Key Task Foundation Item of Shaanxi Province (Grant No 2002K05-G9)
文摘The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.
基金Supported by the National Natural Science Foundation of China under Grant No.61379153the New Century Excellent Talents in University,China(NCET-11-0510)+1 种基金partly by the Research Plan Projects of Science–Technology Department of Hunan Province under Grant No.2012TZ2017the Construct Program of the Key Discipline in Hunan Province
文摘We extend an optimal entanglement distillation of the triplet Greenberger–Horne–Zeilinger(GHZ) state via entanglement concentrating in the three-partite partially electron-spin-entangled systems. Two entanglement concentration protocols are similarly designed in detail with the post-selection in quantum-dot(QD) and micro-cavity coupled systems. The proposed protocol can be repeated several rounds to achieve an optimal success probability with an assistance of the ancillary QD, where only the single photon needs to pass through the micro-cavity for each round. It increases the total success probability of the distillation even if the implemented cavity is imperfect in practice during the whole process.
