This paper proposes a scheme for realization of a three-qubit Toffoli gate operation using three four-level atoms by a selective atom-field interaction in a cavity quantum electrodynamics system. In the proposed proto...This paper proposes a scheme for realization of a three-qubit Toffoli gate operation using three four-level atoms by a selective atom-field interaction in a cavity quantum electrodynamics system. In the proposed protocol, the quantum information is encoded on the stable ground states of atoms, and atomic spontaneous emission is negligible as the large atom-avity detuning effectively suppresses the spontaneous decay of the atoms. The influence of the dissipation on fidelity and success probability of the three-qubit Toffoli gate is also discussed. The scheme can also be applied to realize an N-qubit Toffoli gate and the interaction time required does not rise with increasing the number of qubits.展开更多
This paper proposes two schemes for implementing three-qubit Toffoli gate with an atom （as target qubit） sent through a two-mode cavity （as control qubits）. The first scheme is based on the large-detuning atom cav...This paper proposes two schemes for implementing three-qubit Toffoli gate with an atom （as target qubit） sent through a two-mode cavity （as control qubits）. The first scheme is based on the large-detuning atom cavity field interaction and the second scheme is based on the resonant atom-field interaction. Both the situations with and without cavity decay and atomic spontaneous emission are considered. The advantages and the experimental feasibility of these two schemes are discussed.展开更多
In this paper, the synthesis and implementation of three-qubit SWAP gate is discussed. The three-qubit SWAP gate can be decomposed into product of 2 two-qubit SWAP gates, and it can be realized by 6 CNOT gates. Resear...In this paper, the synthesis and implementation of three-qubit SWAP gate is discussed. The three-qubit SWAP gate can be decomposed into product of 2 two-qubit SWAP gates, and it can be realized by 6 CNOT gates. Research illustrated that although the result is very simple, the current methods of matrix decomposition for multi-qubit gate can not get that. Then the implementation of three-qubit SWAP gate in the three spin system with Ising interaction is investigated and the sequence of control pulse and drift process to implement the gate is given. It needs 23 control pulses and 12 drift processes. Since the interaction can not be switched on and off at will, the realization of three-qubit SWAP gate in specific quantum system also can not simply come down to 2 two-qubit SWAP gates.展开更多
We propose a potentially practical scheme to implement an approximate three-qubit Toffoli gate by a single resonant interaction in dissipative cavity QED in which the cavity mode decay and atomic spontaneous emission ...We propose a potentially practical scheme to implement an approximate three-qubit Toffoli gate by a single resonant interaction in dissipative cavity QED in which the cavity mode decay and atomic spontaneous emission are considered. The scheme does not require two-qubit controlled-NOT gates but uses a three-qubit phase gate and two Hadamard gates, where the approximate phase gate can be implemented by only a single dissipative resonant interaction of atoms with the cavity mode. Discussions are made for the advantages and the experimental feasibility of our scheme.展开更多
We propose a potentially practical scheme for implementing an n-qubit Toffoli gate by elaborately controllingthe transport of ultracold ions through stationary laser beams.Conditioned on the uniform ionic transport ve...We propose a potentially practical scheme for implementing an n-qubit Toffoli gate by elaborately controllingthe transport of ultracold ions through stationary laser beams.Conditioned on the uniform ionic transport velocity,the n-qubit Toffoli gate can be realized with high fidelity and high successful probability under current experimentalconditions,which depends on a single resonant interaction with n trapped ions and has constant implementation timewith the increase of qubits.We show that the increase of the ion number can improve the fidelity and the successfulprobability of the Toffoli gate.展开更多
In this paper, we demonstrate n-party controlled unitary gate implementations locally on arbitrary remote state through linear entangled channel where control parties share entanglement with the adjacent control parti...In this paper, we demonstrate n-party controlled unitary gate implementations locally on arbitrary remote state through linear entangled channel where control parties share entanglement with the adjacent control parties and only one of them shares entanglement with the target party. In such a network, we describe the protocol of simultaneous implementation of controlled-Hermitian gate starting from three party scenarios. We also explicate the implementation of three party controlled-Unitary gates, a generalized form of Toffoli gate and subsequently generalize the protocol for n-party using minimal cost.展开更多
基金Project supported by the Natural Science Foundation of Hunan Province,China (Grant No 06JJ50118)
文摘This paper proposes a scheme for realization of a three-qubit Toffoli gate operation using three four-level atoms by a selective atom-field interaction in a cavity quantum electrodynamics system. In the proposed protocol, the quantum information is encoded on the stable ground states of atoms, and atomic spontaneous emission is negligible as the large atom-avity detuning effectively suppresses the spontaneous decay of the atoms. The influence of the dissipation on fidelity and success probability of the three-qubit Toffoli gate is also discussed. The scheme can also be applied to realize an N-qubit Toffoli gate and the interaction time required does not rise with increasing the number of qubits.
基金supported by the National Natural Science Foundation of China (Grant No 60667001)
文摘This paper proposes two schemes for implementing three-qubit Toffoli gate with an atom （as target qubit） sent through a two-mode cavity （as control qubits）. The first scheme is based on the large-detuning atom cavity field interaction and the second scheme is based on the resonant atom-field interaction. Both the situations with and without cavity decay and atomic spontaneous emission are considered. The advantages and the experimental feasibility of these two schemes are discussed.
基金Supported by the Natural Science Foundation of Jiangsu Education Bureau under Grant No.09KJB140010the Project Prepared for National Natural Science Foundation of Xuzhou Normal University under Grant No.08XLY03
文摘In this paper, the synthesis and implementation of three-qubit SWAP gate is discussed. The three-qubit SWAP gate can be decomposed into product of 2 two-qubit SWAP gates, and it can be realized by 6 CNOT gates. Research illustrated that although the result is very simple, the current methods of matrix decomposition for multi-qubit gate can not get that. Then the implementation of three-qubit SWAP gate in the three spin system with Ising interaction is investigated and the sequence of control pulse and drift process to implement the gate is given. It needs 23 control pulses and 12 drift processes. Since the interaction can not be switched on and off at will, the realization of three-qubit SWAP gate in specific quantum system also can not simply come down to 2 two-qubit SWAP gates.
基金The project supported by National Natural Science Foundation of China under Grant No.10774042National Fundamental Basic Research Program of China under Grant No.2005CB724502+2 种基金Natural Science Foundation of Hunan Province under Grant No.05JJ30005the Scientific Research Fund of Educational Department of Hunan Province under Grant No.05C756the Scientific Research Fund of Hunan Institute of Humanity and Science and Technology under Grant No.2005A008
文摘We propose a potentially practical scheme to implement an approximate three-qubit Toffoli gate by a single resonant interaction in dissipative cavity QED in which the cavity mode decay and atomic spontaneous emission are considered. The scheme does not require two-qubit controlled-NOT gates but uses a three-qubit phase gate and two Hadamard gates, where the approximate phase gate can be implemented by only a single dissipative resonant interaction of atoms with the cavity mode. Discussions are made for the advantages and the experimental feasibility of our scheme.
基金supported by National Natural Science Foundation of China under Grant Nos.10774163 and 10774042partly by the National Fundamental Research Program of China under Grant Nos.2005CB724502 and 2006CB921203
文摘We propose a potentially practical scheme for implementing an n-qubit Toffoli gate by elaborately controllingthe transport of ultracold ions through stationary laser beams.Conditioned on the uniform ionic transport velocity,the n-qubit Toffoli gate can be realized with high fidelity and high successful probability under current experimentalconditions,which depends on a single resonant interaction with n trapped ions and has constant implementation timewith the increase of qubits.We show that the increase of the ion number can improve the fidelity and the successfulprobability of the Toffoli gate.
文摘In this paper, we demonstrate n-party controlled unitary gate implementations locally on arbitrary remote state through linear entangled channel where control parties share entanglement with the adjacent control parties and only one of them shares entanglement with the target party. In such a network, we describe the protocol of simultaneous implementation of controlled-Hermitian gate starting from three party scenarios. We also explicate the implementation of three party controlled-Unitary gates, a generalized form of Toffoli gate and subsequently generalize the protocol for n-party using minimal cost.
