We put forward a simple scheme for one-step realization of a two-qubit SWAP gate with SQUIDs （superconducting quantum-interference devices） in cavity QED via Raman transition. In this scheme, the cavity field is onl...We put forward a simple scheme for one-step realization of a two-qubit SWAP gate with SQUIDs （superconducting quantum-interference devices） in cavity QED via Raman transition. In this scheme, the cavity field is only virtually excited and thus the cavity decay is suppressed. The SWAP gate is realized by using only two lower fiux states of the SQUID system and the excited state would not be excited. Therefore, the effect of decoherence caused from the levels of the SQUID system is possibly minimized. The scheme can also be used to implement the SWAP gate with atoms.展开更多
In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices （SQUIDs） and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only ...In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices （SQUIDs） and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can he realized at a high speed, which is important in view of decoherence.展开更多
We propose a scheme for generating a maximally entangled state of two three-level superconducting quantum interference devices （SQUIDs） by using a quantized cavity field and classical microwave pluses in cavity. In ...We propose a scheme for generating a maximally entangled state of two three-level superconducting quantum interference devices （SQUIDs） by using a quantized cavity field and classical microwave pluses in cavity. In this scheme, no quantum information will be transferred from the SQUIDs to the cavity since the cavity field is only virtually excited. Thus, the cavity decay is suppressed during the entanglement generation.展开更多
We investigate the influence of the vacuum-induced coherence on one- and two-photon absorption of the transient process in a four-level Y-type atomic system. We find that the one- and two-photon t, ransient absorption...We investigate the influence of the vacuum-induced coherence on one- and two-photon absorption of the transient process in a four-level Y-type atomic system. We find that the one- and two-photon t, ransient absorption and amplification properties are quite sensitive to the vacuum-induced coherence. It is also shown that the one- and two-photon absorption spectra of the transient process can be dramatically affected by modulating the relative phase of the applied fields. By apprdpriately choosing the relative phase, the amplification of the probe field can be achieved.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
We present a scheme to entangle fields in multiple cavities. Our scheme is based on the resonant interaction of a ≡-type three-level atom with the cavity fields for precalculated interaction time, which enables us to...We present a scheme to entangle fields in multiple cavities. Our scheme is based on the resonant interaction of a ≡-type three-level atom with the cavity fields for precalculated interaction time, which enables us to generate a quantum entangled Greenberger-Horn-Zeilinger （GHZ） state of fields in multiple cavities. In principle, the scheme can be also generalized to generate N-party GHZ state. The required experimental techniques are within the scope of what can be obtained in the microwave cavity QED set up.展开更多
We propose a scheme for generating the maximally entangled states of many superconducting quantum interference devices （SQUIDs） by using a quantized cavity field and classical microwave pulses in cavity. In the sche...We propose a scheme for generating the maximally entangled states of many superconducting quantum interference devices （SQUIDs） by using a quantized cavity field and classical microwave pulses in cavity. In the scheme, the maximally entangled states can be generated without requiring the measurement and individual addressing of the SQUIDs.展开更多
In this paper, the theoretical investigation of remote preparation of an entangledstate is studied in nonideal conditions. Our studies include two parts. In the first part, we consider the remote state preparation （...In this paper, the theoretical investigation of remote preparation of an entangledstate is studied in nonideal conditions. Our studies include two parts. In the first part, we consider the remote state preparation （RSP） of an entangled state through two equally noisy quantum channel states, namely, a mixture of Bell states. Studies show there is a particular mixed-state channel for which all pure entangled states remain entangled after this inexact RSP. In the second part, we suppose that noises which quantum channels suffer from can be expressed as the Lindblad operators. The master equation of the system can be expressed in the Lindblad form. Through solving the master equation, we calculate the fidelity as a function of decoherence rates and parameters of the state to be prepared. For a given entangled state, we investigate the influence of different types of noises on the fidelity.展开更多
基金National Natural Science Foundation of China under Grant No.10704017the Scientific Research Program of the Educational Department of Hubei Province under Grant No.D200634001
文摘We put forward a simple scheme for one-step realization of a two-qubit SWAP gate with SQUIDs （superconducting quantum-interference devices） in cavity QED via Raman transition. In this scheme, the cavity field is only virtually excited and thus the cavity decay is suppressed. The SWAP gate is realized by using only two lower fiux states of the SQUID system and the excited state would not be excited. Therefore, the effect of decoherence caused from the levels of the SQUID system is possibly minimized. The scheme can also be used to implement the SWAP gate with atoms.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 60478029. Acknowledgments We would like to thank Prof. Wu Ying for enlightening discussions
文摘In this paper, a scheme is proposed to create the entanglement of two superconducting quantum-interference devices （SQUIDs） and implement a two-quhit quantum phase gate between two SQUIDs in cavity. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can he realized at a high speed, which is important in view of decoherence.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 60478029
文摘We propose a scheme for generating a maximally entangled state of two three-level superconducting quantum interference devices （SQUIDs） by using a quantized cavity field and classical microwave pluses in cavity. In this scheme, no quantum information will be transferred from the SQUIDs to the cavity since the cavity field is only virtually excited. Thus, the cavity decay is suppressed during the entanglement generation.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 60478029 and 10575040 The authors would like to thank Prof.Ying Wu for stimulating discussion.
文摘We investigate the influence of the vacuum-induced coherence on one- and two-photon absorption of the transient process in a four-level Y-type atomic system. We find that the one- and two-photon t, ransient absorption and amplification properties are quite sensitive to the vacuum-induced coherence. It is also shown that the one- and two-photon absorption spectra of the transient process can be dramatically affected by modulating the relative phase of the applied fields. By apprdpriately choosing the relative phase, the amplification of the probe field can be achieved.
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 in part by National Nat, ural Science Foundation of China under Grant No. 60478029 We would like to thank professor Wu Ying for enlightening discussions
文摘We present a scheme to entangle fields in multiple cavities. Our scheme is based on the resonant interaction of a ≡-type three-level atom with the cavity fields for precalculated interaction time, which enables us to generate a quantum entangled Greenberger-Horn-Zeilinger （GHZ） state of fields in multiple cavities. In principle, the scheme can be also generalized to generate N-party GHZ state. The required experimental techniques are within the scope of what can be obtained in the microwave cavity QED set up.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 60478029,Acknowledgment We would like to thank Prof. Wu Ying for enlightening discussions.
文摘We propose a scheme for generating the maximally entangled states of many superconducting quantum interference devices （SQUIDs） by using a quantized cavity field and classical microwave pulses in cavity. In the scheme, the maximally entangled states can be generated without requiring the measurement and individual addressing of the SQUIDs.
基金The project partially supported by National Natural Science Foundation of China under Grant Nos. 90103026 and 60478029 . We would like to acknowledge useful discussions with Prof. Wu Ying.
文摘In this paper, the theoretical investigation of remote preparation of an entangledstate is studied in nonideal conditions. Our studies include two parts. In the first part, we consider the remote state preparation （RSP） of an entangled state through two equally noisy quantum channel states, namely, a mixture of Bell states. Studies show there is a particular mixed-state channel for which all pure entangled states remain entangled after this inexact RSP. In the second part, we suppose that noises which quantum channels suffer from can be expressed as the Lindblad operators. The master equation of the system can be expressed in the Lindblad form. Through solving the master equation, we calculate the fidelity as a function of decoherence rates and parameters of the state to be prepared. For a given entangled state, we investigate the influence of different types of noises on the fidelity.
