Beyond the Lamb-Dicke limit, this paper investigates the squeezing properties of the trapped ion in the travelling- wave laser. It shows that the squeezing properties of the trapped ion in the travelling-wave laser ar...Beyond the Lamb-Dicke limit, this paper investigates the squeezing properties of the trapped ion in the travelling- wave laser. It shows that the squeezing properties of the trapped ion in the travelling-wave laser are strongly affected by the sideband number k, the Lamb-Dicke parameter η and the initial average phonon number.展开更多
In the paper, taking the atomic EPR entanglement of quantum teleportation of atomic state in thermal environment damping-density operator approach, and the average fidelities are channel state ｜φ = （1/√2）（｜00）...In the paper, taking the atomic EPR entanglement of quantum teleportation of atomic state in thermal environment damping-density operator approach, and the average fidelities are channel state ｜φ = （1/√2）（｜00） ＋ ｜11〉） is more robust than ｜φ｜ they are subject to the dissipative environments. states as quantum channel, we investigate the fidelity and vacuum reservoir by means of quantum theory of calculated, the results show that the atomic quantum = （1/√2）（｜01〉 ＋ ｜10〉） in teleportation process when they are subject to the dissipative environments.展开更多
We propose an effective scheme for the entanglement concentration of a four-particle state via entanglement swapping in an ion trap. Taking the maximally entangled state after concentration as a quantum channel, we ca...We propose an effective scheme for the entanglement concentration of a four-particle state via entanglement swapping in an ion trap. Taking the maximally entangled state after concentration as a quantum channel, we can faithfully and determinatively teleport quantum entangled states from Alice to Bob without the joint Bell-state measurement. In the process of constructing the quantum channel, we adopt entanglement swapping to avoid the decrease of entanglement during the distribution of particles. Thus our scheme provides a new prospect for quantum teleportation over a longer distance. Furthermore, the success probability of our scheme is 1.0.展开更多
The entanglement dynamics of two-qubit systems in different quantum noises are investigated by means of the operator-sum representation method. We find that, except for the amplitude damping and phase damping quantum ...The entanglement dynamics of two-qubit systems in different quantum noises are investigated by means of the operator-sum representation method. We find that, except for the amplitude damping and phase damping quantum noise, the sudden death of entanglement is always observed in different two-qubit systems with generalized amplitude damping and depolarizing quantum noise.展开更多
We propose a scheme to implement an unconventional geometric logic gate separately in a two-mode cavity and a multi-mode cavity assisted by a strong classical driving field. The effect of the cavity decay is included ...We propose a scheme to implement an unconventional geometric logic gate separately in a two-mode cavity and a multi-mode cavity assisted by a strong classical driving field. The effect of the cavity decay is included in the investigation. The numerical calculation is carried out, and the result shows that our scheme is more tolerant to cavity decay than the previous one because the time consumed for finishing the logic gate is doubly reduced.展开更多
This paper reports that a quantum dense coding can be implemented with ions confined in a linear trap and interacting with laser beams. The scheme is insensitive to the interaction between the quantum channel and the ...This paper reports that a quantum dense coding can be implemented with ions confined in a linear trap and interacting with laser beams. The scheme is insensitive to the interaction between the quantum channel and the environment. The Bell-state measurement is not involved and the probability of success in our scheme is 1.0.展开更多
We present a simple scheme for the probabilistic generation of the $n$-qubit W state of three-level systems in cavity quantum electrodynamics. Once the W state is prepared, it will be insensitive to the spontaneous em...We present a simple scheme for the probabilistic generation of the $n$-qubit W state of three-level systems in cavity quantum electrodynamics. Once the W state is prepared, it will be insensitive to the spontaneous emission of atoms due to the fact that only the two degenerate ground states of the three-level atoms are involved. With time evolution of the system, the success probability and the experimental feasibility are also discussed.展开更多
The ballistic thermoelectric properties in bended graphene nanoribbons（GNRs） are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneli...The ballistic thermoelectric properties in bended graphene nanoribbons（GNRs） are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneling effect occurs in the metallic–semiconducting linked ZZ-GNRs（the bended GNRs with zigzag edge leads）. The electron-wave quantum interference effect occurs in the metallic–metallic linked AA-GNRs（the bended GNRs with armchair edge leads）.These different physical mechanisms lead to the large Seebeck coefficient S and high electron conductance in bended ZZGNRs/AA-GNRs. Combined with the reduced lattice thermal conduction, the significant enhancement of the figure of merit ZT is predicted. Moreover, we find that the ZTmax（the maximum peak of ZT） is sensitive to the structural parameters. It can be conveniently tuned by changing the interbend length of bended GNRs. The magnitude of ZT ranges from the 0.15 to 0.72. Geometry-controlled ballistic thermoelectric effect offers an effective way to design thermoelectric devices such as thermocouples based on graphene.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025）.
文摘Beyond the Lamb-Dicke limit, this paper investigates the squeezing properties of the trapped ion in the travelling- wave laser. It shows that the squeezing properties of the trapped ion in the travelling-wave laser are strongly affected by the sideband number k, the Lamb-Dicke parameter η and the initial average phonon number.
基金Supported by the Natural Science Foundation of Hunan Province of China under Grant No.10JJ3088Funds of Hunan Education Bureau under Grant No.10C0616the Key Research Foundation of the Education Bureau of Hunan Province under Grant Nos.10A026 and 08A015
文摘In the paper, taking the atomic EPR entanglement of quantum teleportation of atomic state in thermal environment damping-density operator approach, and the average fidelities are channel state ｜φ = （1/√2）（｜00） ＋ ｜11〉） is more robust than ｜φ｜ they are subject to the dissipative environments. states as quantum channel, we investigate the fidelity and vacuum reservoir by means of quantum theory of calculated, the results show that the atomic quantum = （1/√2）（｜01〉 ＋ ｜10〉） in teleportation process when they are subject to the dissipative environments.
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025）.
文摘We propose an effective scheme for the entanglement concentration of a four-particle state via entanglement swapping in an ion trap. Taking the maximally entangled state after concentration as a quantum channel, we can faithfully and determinatively teleport quantum entangled states from Alice to Bob without the joint Bell-state measurement. In the process of constructing the quantum channel, we adopt entanglement swapping to avoid the decrease of entanglement during the distribution of particles. Thus our scheme provides a new prospect for quantum teleportation over a longer distance. Furthermore, the success probability of our scheme is 1.0.
基金supported by the Natural Science Foundation of Hunan Province of China (Grant No. 10JJ3088)the Key Research Foundation of the Education Bureau of Hunan Province of China (Grant No. 08A015)the Funds of the Hunan Education Bureau of China (Grant Nos. 10C0616 and 08C344)
文摘The entanglement dynamics of two-qubit systems in different quantum noises are investigated by means of the operator-sum representation method. We find that, except for the amplitude damping and phase damping quantum noise, the sudden death of entanglement is always observed in different two-qubit systems with generalized amplitude damping and depolarizing quantum noise.
基金Project supported by the National Natural Science Foundation of China(Grant No.50874041)the Funds of Hunan Educational Bureau,China(Grant No.09C314)
文摘We propose a scheme to implement an unconventional geometric logic gate separately in a two-mode cavity and a multi-mode cavity assisted by a strong classical driving field. The effect of the cavity decay is included in the investigation. The numerical calculation is carried out, and the result shows that our scheme is more tolerant to cavity decay than the previous one because the time consumed for finishing the logic gate is doubly reduced.
基金Project supported by the Key Education Foundation of Hunan Province, China (Grant No 06A038)
文摘This paper reports that a quantum dense coding can be implemented with ions confined in a linear trap and interacting with laser beams. The scheme is insensitive to the interaction between the quantum channel and the environment. The Bell-state measurement is not involved and the probability of success in our scheme is 1.0.
文摘We present a simple scheme for the probabilistic generation of the $n$-qubit W state of three-level systems in cavity quantum electrodynamics. Once the W state is prepared, it will be insensitive to the spontaneous emission of atoms due to the fact that only the two degenerate ground states of the three-level atoms are involved. With time evolution of the system, the success probability and the experimental feasibility are also discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.61401153)the Natural Science Foundation of Hunan Province,China(Grant Nos.2015JJ2050 and 14JJ3126)
文摘The ballistic thermoelectric properties in bended graphene nanoribbons（GNRs） are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneling effect occurs in the metallic–semiconducting linked ZZ-GNRs（the bended GNRs with zigzag edge leads）. The electron-wave quantum interference effect occurs in the metallic–metallic linked AA-GNRs（the bended GNRs with armchair edge leads）.These different physical mechanisms lead to the large Seebeck coefficient S and high electron conductance in bended ZZGNRs/AA-GNRs. Combined with the reduced lattice thermal conduction, the significant enhancement of the figure of merit ZT is predicted. Moreover, we find that the ZTmax（the maximum peak of ZT） is sensitive to the structural parameters. It can be conveniently tuned by changing the interbend length of bended GNRs. The magnitude of ZT ranges from the 0.15 to 0.72. Geometry-controlled ballistic thermoelectric effect offers an effective way to design thermoelectric devices such as thermocouples based on graphene.
