Chinese Physics B

One scheme for remote quantum logical gates with the assistance of a classical field

Yan‐Ling Li, Mao-Fa Fang, Zeng Ke

Published Jan 1, 2010• 3 citations

Abstract

A scheme, based on the two two-level atoms resonantly driven by the classical field separately trapped in two cavities coupled by an optical fibre, for the implementation of remote two-qubit gates is investigated. It is found that the quantum controlled-phase and swap gates can be achieved with the assistance of the classical field when there are detunings of the coupling quantum fields. Moreover, the influence of the dissipation of the cavities and the optical fibre is analysed while the spontaneous emission of the atoms can be effectively suppressed by introducing λ-type atoms.

DOI: 10.1088/1674-1056/19/1/010307

Related papers

Implementation of a remote three-qubit controlled-Z gate for atoms separately trapped in cavities coupled by optical fibres

Yan‐Ling Li, Mao-Fa Fang, Xing Mao Xiao +1 more

We propose a scheme for implementing a remote three-qubit controlled-Z gate with three atoms separately trapped in three distant cavities coupled by optical fibres. The influences of various decoherence processes, such as spontaneous emission of the atoms and photon leakage of the cavities and the optical fibres, on the fidelity are also investigated. It is found that the gate can be implemented with high fidelity even when these decoherence processes are considered. This scheme can be extended to the implementation of a remote N -qubit controlled-Z gate with N atoms separately trapped in N distant cavities coupled by optical fibres.

Journal of Physics B Atomic Molecular and Optical PhysicsAug 4, 20107 citations

Cavity-QED-based phase gate for photonic qubits

Yuli Dong, Xu‐Bo Zou, ShengLi Zhang +3 more

We present a two-qubit phase gate for photonic qubits using a three-level atom trapped in an optical cavity. In the scheme, the two ground states are coupled to the excited state by two cavity fields, respectively, and one of them is driven by a classical laser field. It is shown that, based on the large-detuning condition, the decay of atomic spontaneous emission can be effectively suppressed. The influence of cavity decay on our scheme is also investigated.

Journal of Modern OpticsJun 20, 200913 citations

Multiatom and resonant interaction scheme for quantum state transfer and logical gates between two remote cavities via an optical fiber

Zhang‐qi Yin, Fuli Li

A system consisting of two single-mode cavities spatially separated and connected by an optical fiber and multiple two-level atoms trapped in the cavities is considered. If the atoms resonantly and collectively interact with the local cavity fields but there is no direct interaction between the atoms, we show that an ideal quantum state transfer and highly reliable quantum swap, entangling, and controlled-Z gates can be deterministically realized between the distant cavities. We find that the operation of state transfer and swap, entangling, and controlled-Z gates can be greatly speeded up as number of the atoms in the cavities increases. We also notice that the effects of spontaneous emission of atoms and photon leakage out of cavity on the quantum processes can also be greatly diminished in the multiatom case.

arXiv:quant-ph/0606152Physical Review AJan 23, 2007220 citations

A SCHEME FOR REALIZATION OF TWO-QUBIT LOGIC GATES IN CAVITY QED

Bao‐Long Fang, Hong-Bo Wan, Ye Liu

We propose a simple scheme for realizing two-qubit logic gate in cavity QED. In our scheme, the quantum controlled-not gate, phase gate and swap gate can be implemented without the ancillary level. The quantum controlled-not gate and phase gate can be realized easily by only one interaction between atoms and a highly detuned cavity mode with the assistance of a strong classical field. Thus, the scheme is insensitive to both the cavity decay and the thermal field.

Modern Physics Letters BJan 10, 20100 citations

Quantum logic operations on two distant atoms trapped in two optical-fibre-connected cavities

Ying-Qiao Zhang, Shou Zhang, Kyu-Hwang Yeon +1 more

Based on the coupling of two distant three-level atoms in two separate optical cavities connected with two optical fibres, schemes on the generation of several two-qubit logic gates are discussed under the conditions of Δ = δ − 2νcos π k /2 ≫ g /2 and ν ∼ g . Discussion and analysis of the fidelity, gate time and experimental setups show that our schemes are feasible with current optical cavity, atomic trap and optical fibre techniques. Moreover, the atom—cavity—fibre coupling can be used to generate an N -qubit nonlocal entanglement and transfer quantum information among N distant atoms by arranging N atom—cavity assemblages in a line and connecting each two adjacent cavities with two optical fibres.

Chinese Physics BDec 1, 20111 citation

Control of entanglement and two-qubit quantum gates with atoms crossing a detuned optical cavity

Gonta, D., Fritzsche, S.

A scheme is proposed to generate an entangled state between two (Λ-type) four-level atoms that interact effectively by means of a detuned optical cavity and a laser beam that acts perpendicularly to the cavity axis.It is shown how the degree of entanglement for two atoms passing through the cavity can be controlled by manipulating their velocity and the (initial) distance between the atoms.In addition, three realistic schemes are suggested to implement the two-qubit gates within the framework of the suggested atom-cavity-laser setup, namely, the i-swap gate, controlled-Z gate, and the controlled-NOT gate.For all these schemes, we analyze and discuss the atomic velocities and inter-atomic distances for which these gates are realized most reliably.

Jan 1, 20094 citations