We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-p...We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-photon Jaynes-Cummings model under certain conditions.展开更多
We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitr...We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitrary two-atom pure state to be teleported is entangled or not, our teleportation scheme can always be probabilistically realized. The success prohability of teleportation is determined by the smaller coemcients of the two initially entangled atom pairs.展开更多
An alternative scheme is proposed to transfer quantum states and prepare a quantum network in cavity QED. It is based on the interaction of a two-mode cavity field with a three-level V-type atom. In the scheme, the at...An alternative scheme is proposed to transfer quantum states and prepare a quantum network in cavity QED. It is based on the interaction of a two-mode cavity field with a three-level V-type atom. In the scheme, the atom-cavity field interaction is resonant, thus the time required to complete the quantum state transfer process is greatly shortened, which is very important in view of decoherence. Moreover, the present scheme does not require one mode of the cavities to be initially prepared in one-photon state, thus it is more experimentally feasible than the previous ones.展开更多
Based on superconducting quantum interference devices （SQUIDs） coupled to a cavity, we propose a scheme for implementing a quantum controlled-phase gate （QPG） and Deutsch-Jozsa （D J） algorithm by a controllable ...Based on superconducting quantum interference devices （SQUIDs） coupled to a cavity, we propose a scheme for implementing a quantum controlled-phase gate （QPG） and Deutsch-Jozsa （D J） algorithm by a controllable interaction. In the present scheme, the SQUID works in the charge regime, and the cavity field is ultilized as quantum data-bus, which is sequentially coupled to only one qubit at a time. The interaction between the selected qubit and the data bus, such as resonant and dispersive interaction, can be realized by turning the gate capacitance of each SQUID. Especially, the bus is not excited and thus the cavity decay is suppressed during the implementation of DJ algorithm. For the QPG operation, the mode of the bus is unchanged in the end of the operation, although its mode is really excited during the operations. Finally, for typical experiment data, we analyze simply the experimental feasibility of the proposed scheme. Based on the simple operation, our scheme may be realized in this solid-state system, and our idea may be realized in other systems.展开更多
We present an experimentally feasible scheme for teleportation of an arbitrary unknown two-atom entangled state by using two-atom Bell states in driven thermal cavities. In this scheme, the effects of thermal field an...We present an experimentally feasible scheme for teleportation of an arbitrary unknown two-atom entangled state by using two-atom Bell states in driven thermal cavities. In this scheme, the effects of thermal field and cavity decay can be all eliminated. Moreover, the present scheme is feasible according to current technologies.展开更多
We present analytical solutions describing quantized vacuum field in a one-dimensional cavity with one of its two mirrors fixed and another vibrating in simple harmonic form. These solutions are accurate up to the sec...We present analytical solutions describing quantized vacuum field in a one-dimensional cavity with one of its two mirrors fixed and another vibrating in simple harmonic form. These solutions are accurate up to the second order of the oscillating magnitude and they are uniformly valid for all time. We obtain the simple analytical expression for the energy density of the field which explicitly manifests that for a cavity vibrating at its -th eigenfrequency, traveling wave packets emerge in the finite part of the field energy density, and their amplitudes grow while their widths shrink in time, representing a large concentration of energy. The finite part of the field energy density originating from the oscillations is shown to be proportional to the factor .展开更多
We propose a scheme to implement a two-qubit conditional quantum phase gate via a single mode cavity and a cascade four-level atom assisted by a classical laser. The quantum information is encoded.on the Flock states ...We propose a scheme to implement a two-qubit conditional quantum phase gate via a single mode cavity and a cascade four-level atom assisted by a classical laser. The quantum information is encoded.on the Flock states of the cavity mode and the two metastable ground states of the atom. Even under the condition of systematic dissipations, this scheme can also be realized with fidelity of 98.6% and success probability of 0.767.展开更多
In this paper, a theoretical scheme is proposed to implement the Deutsch-Jozsa algorithm with SQUIDs （superconducting quantum-interference devices） in cavity via Raman transition. The scheme only requires a quantize...In this paper, a theoretical scheme is proposed to implement the Deutsch-Jozsa algorithm with SQUIDs （superconducting quantum-interference devices） in cavity via Raman transition. The scheme only requires a quantized cavity field and classical microwave pulses. In this scheme, no transfer of quantum information between the SQUIDs and the cavity is required, the cavity field is only virtually excited and thus the cavity decay is suppressed.展开更多
A scheme is proposed for the generation of entangled states for multiple atoms trapped in a cavity by detecting photon decay. The scheme is valid no matter when the effective atom-cavity coupling strength is larger th...A scheme is proposed for the generation of entangled states for multiple atoms trapped in a cavity by detecting photon decay. The scheme is valid no matter when the effective atom-cavity coupling strength is larger than the cavity decay rate or not, which is of importance in view of experiment. The fidelity of entanglement is insensitive to the inefticiency of the photo-detector. The scheme does not require a photon to be initially injected into the cavity.展开更多
The atom fidelity is investigated in a system consisting of Mtwo-level atoms and M single-mode fields by use of complete quantum theory and numerical evaluation method. The influences of various system parameters on t...The atom fidelity is investigated in a system consisting of Mtwo-level atoms and M single-mode fields by use of complete quantum theory and numerical evaluation method. The influences of various system parameters on the evolution of atomic fidelity are studied. The results show that the atomic fidelity evolves in a Rabi oscillation manner. The oscillation frequency is mainly modulated by the coupling strength between atoms and light field, the atomic transition probabilities and the average photon numbers. Other factors hardly impact on the atomic fidelity. The present results may provide a useful approach to the maintenance of the atomic fidelity in the atom cavity field systems.展开更多
A potentially practical scheme is proposed to realize optical quantum simulation of artificial Abelian gauge field in a scalable architecture consisting of cold atomic ensembles with optical cavities.In the present mo...A potentially practical scheme is proposed to realize optical quantum simulation of artificial Abelian gauge field in a scalable architecture consisting of cold atomic ensembles with optical cavities.In the present model,the collective excitations of cold atomic ensembles can be converted to the bosonic modes within the low-excitation limit,where the structure of two-dimension(2D)square plaquette enables the polaritons to move like a charged particle subjected to an external magnetic field.We find that the energy spectrum of this hybrid system exhibits a shape of Hofstadter buttery.Our work provides a different perspective to the quantum simulation of condensed matter and many-body physics in the context of cavity quantum electrodynamics.The experimental feasibility are justified using the existing techniques.展开更多
文摘We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-photon Jaynes-Cummings model under certain conditions.
基金The project supported by National Natural Science Foundation of China under Grant No. 60578050
文摘We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED. It is Shown that no matter whether the arbitrary two-atom pure state to be teleported is entangled or not, our teleportation scheme can always be probabilistically realized. The success prohability of teleportation is determined by the smaller coemcients of the two initially entangled atom pairs.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10225421 and 10674025
文摘An alternative scheme is proposed to transfer quantum states and prepare a quantum network in cavity QED. It is based on the interaction of a two-mode cavity field with a three-level V-type atom. In the scheme, the atom-cavity field interaction is resonant, thus the time required to complete the quantum state transfer process is greatly shortened, which is very important in view of decoherence. Moreover, the present scheme does not require one mode of the cavities to be initially prepared in one-photon state, thus it is more experimentally feasible than the previous ones.
基金The project supported by the Natural Science Foundation of Hunan Province under Grant No. 06jj50014, Key Project Foundation of the Education Commission of Hunan Province under Grant No. 06A055 and National Natural Science Foundation of China under Grant No. 10574126
文摘Based on superconducting quantum interference devices （SQUIDs） coupled to a cavity, we propose a scheme for implementing a quantum controlled-phase gate （QPG） and Deutsch-Jozsa （D J） algorithm by a controllable interaction. In the present scheme, the SQUID works in the charge regime, and the cavity field is ultilized as quantum data-bus, which is sequentially coupled to only one qubit at a time. The interaction between the selected qubit and the data bus, such as resonant and dispersive interaction, can be realized by turning the gate capacitance of each SQUID. Especially, the bus is not excited and thus the cavity decay is suppressed during the implementation of DJ algorithm. For the QPG operation, the mode of the bus is unchanged in the end of the operation, although its mode is really excited during the operations. Finally, for typical experiment data, we analyze simply the experimental feasibility of the proposed scheme. Based on the simple operation, our scheme may be realized in this solid-state system, and our idea may be realized in other systems.
基金＊The project supported by National Natural Science Foundation of China under Grant Nos. 10304022 and 60677001, the Science and Technology Fand of Anhui Province for 0utstanding Youth under Grant No. 06042087, the General Fund of the Educational Committee of Anhui Province under Grant No. 2006KJ260B, the Key Fund of the Ministry of Education of China under Grant No. 206063, the Natural Science Foundation of Hubei Province of China under Grant No. 2006ABA354, and the Foundation of the State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics of CAS under Grant No. T152615
文摘We present an experimentally feasible scheme for teleportation of an arbitrary unknown two-atom entangled state by using two-atom Bell states in driven thermal cavities. In this scheme, the effects of thermal field and cavity decay can be all eliminated. Moreover, the present scheme is feasible according to current technologies.
文摘We present analytical solutions describing quantized vacuum field in a one-dimensional cavity with one of its two mirrors fixed and another vibrating in simple harmonic form. These solutions are accurate up to the second order of the oscillating magnitude and they are uniformly valid for all time. We obtain the simple analytical expression for the energy density of the field which explicitly manifests that for a cavity vibrating at its -th eigenfrequency, traveling wave packets emerge in the finite part of the field energy density, and their amplitudes grow while their widths shrink in time, representing a large concentration of energy. The finite part of the field energy density originating from the oscillations is shown to be proportional to the factor .
基金The project supported by National Natural Science Foundation of China under Grant No. 10374025
文摘We propose a scheme to implement a two-qubit conditional quantum phase gate via a single mode cavity and a cascade four-level atom assisted by a classical laser. The quantum information is encoded.on the Flock states of the cavity mode and the two metastable ground states of the atom. Even under the condition of systematic dissipations, this scheme can also be realized with fidelity of 98.6% and success probability of 0.767.
基金supported in part by Scientific Research Program of Hubei Provincial Department of Education under Grant No.D200634001Natural Science Foundation of Jiangxi Province under Grant No. 0612006
文摘In this paper, a theoretical scheme is proposed to implement the Deutsch-Jozsa algorithm with SQUIDs （superconducting quantum-interference devices） in cavity via Raman transition. The scheme only requires a quantized cavity field and classical microwave pulses. In this scheme, no transfer of quantum information between the SQUIDs and the cavity is required, the cavity field is only virtually excited and thus the cavity decay is suppressed.
基金The project supported by National Natural Science Foundation of China under Grant No. 10225421 and the Funds from Fuzhou University
文摘A scheme is proposed for the generation of entangled states for multiple atoms trapped in a cavity by detecting photon decay. The scheme is valid no matter when the effective atom-cavity coupling strength is larger than the cavity decay rate or not, which is of importance in view of experiment. The fidelity of entanglement is insensitive to the inefticiency of the photo-detector. The scheme does not require a photon to be initially injected into the cavity.
基金Supported by the National Nature Science Foundation of China under Grant No.11304230Nature Science Foundation of Shaanxi Province under Grant No.2013JM1006+1 种基金the Project of Education Department of Shaanxi Provincial Government under Grant No.2013JK0634the Special Subject Construction of Weinan Normal University under Grant Nos.14TSXK06 and 15ZRRC14
文摘The atom fidelity is investigated in a system consisting of Mtwo-level atoms and M single-mode fields by use of complete quantum theory and numerical evaluation method. The influences of various system parameters on the evolution of atomic fidelity are studied. The results show that the atomic fidelity evolves in a Rabi oscillation manner. The oscillation frequency is mainly modulated by the coupling strength between atoms and light field, the atomic transition probabilities and the average photon numbers. Other factors hardly impact on the atomic fidelity. The present results may provide a useful approach to the maintenance of the atomic fidelity in the atom cavity field systems.
基金supported by the National Natural Science Foundation ofChina(Grant Nos.11372122,10874122 and 11074070)the Program for Excellent Talents at the University of Guangdong Province(GuangdongTeacher Letter[1010]No.79)
文摘A potentially practical scheme is proposed to realize optical quantum simulation of artificial Abelian gauge field in a scalable architecture consisting of cold atomic ensembles with optical cavities.In the present model,the collective excitations of cold atomic ensembles can be converted to the bosonic modes within the low-excitation limit,where the structure of two-dimension(2D)square plaquette enables the polaritons to move like a charged particle subjected to an external magnetic field.We find that the energy spectrum of this hybrid system exhibits a shape of Hofstadter buttery.Our work provides a different perspective to the quantum simulation of condensed matter and many-body physics in the context of cavity quantum electrodynamics.The experimental feasibility are justified using the existing techniques.
