skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Simple scheme for generating an n-qubit W state in cavity QED

Abstract

A simple scheme is proposed to generate an n-qubit W state in cavity QED. Conditioned on no photon leakage from the cavity, the n-qubit W state can be generated by resonant interaction between atoms and the cavity if the cavity is initially prepared in the single-photon state and all the atoms are in the ground states. We check the time evolution of the system involving decay, and show that, since the required interaction time is very short, with present cavity QED techniques, the success probability of our scheme is almost unity.

Authors:
 [1];  [2]; ;  [1]
  1. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China and Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China)
  2. (China)
Publication Date:
OSTI Identifier:
20786800
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevA.73.014302; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; CAVITY RESONATORS; DECAY; GROUND STATES; OPTICS; PHOTON-ATOM COLLISIONS; PHOTONS; PROBABILITY; QUANTUM COMPUTERS; QUANTUM ELECTRODYNAMICS; QUANTUM ENTANGLEMENT; QUBITS; RADIATION PRESSURE

Citation Formats

Deng, Z. J., Graduate School of the Chinese Academy of Sciences, Beijing 100049, Feng, M., and Gao, K. L.. Simple scheme for generating an n-qubit W state in cavity QED. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Deng, Z. J., Graduate School of the Chinese Academy of Sciences, Beijing 100049, Feng, M., & Gao, K. L.. Simple scheme for generating an n-qubit W state in cavity QED. United States. doi:10.1103/PHYSREVA.73.0.
Deng, Z. J., Graduate School of the Chinese Academy of Sciences, Beijing 100049, Feng, M., and Gao, K. L.. Sun . "Simple scheme for generating an n-qubit W state in cavity QED". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20786800,
title = {Simple scheme for generating an n-qubit W state in cavity QED},
author = {Deng, Z. J. and Graduate School of the Chinese Academy of Sciences, Beijing 100049 and Feng, M. and Gao, K. L.},
abstractNote = {A simple scheme is proposed to generate an n-qubit W state in cavity QED. Conditioned on no photon leakage from the cavity, the n-qubit W state can be generated by resonant interaction between atoms and the cavity if the cavity is initially prepared in the single-photon state and all the atoms are in the ground states. We check the time evolution of the system involving decay, and show that, since the required interaction time is very short, with present cavity QED techniques, the success probability of our scheme is almost unity.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 1,
volume = 73,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • Following the proposal by [F. Yamaguchi et al. Phys. Rev. A 66, 010302(R) (2002)], we present an alternative way to implement the two-qubit Grover search algorithm in cavity QED. Compared with Yamaguchi et al.'s proposal, with a strong resonant classical field added, our method is insensitive to both the cavity decay and thermal field, and does not require that the cavity remain in the vacuum state throughout the procedure. Moreover, the qubit definitions are the same for both atoms, which makes the experiment easier. The strictly numerical simulation shows that our proposal is good enough to demonstrate a two-qubit Grover'smore » search with high fidelity.« less
  • We propose a way for generating n-qubit Greenberger-Horne-Zeilinger (GHZ) entangled states with a three-level qubit system and (n-1) four-level qubit systems in a cavity. This proposal does not require identical qubit-cavity coupling constants and thus is tolerant to qubit-system parameter nonuniformity and nonexact placement of qubits in a cavity. The proposal does not require adjustment of the qubit-system level spacings during the entire operation. Moreover, it is shown that entanglement can be deterministically generated using this method and the operation time is independent of the number of qubits. The present proposal is quite general, which can be applied to physicalmore » systems such as various types of superconducting devices coupled to a resonator or atoms trapped in a cavity.« less
  • We propose an approach to realize an n-qubit controlled-U gate with superconducting quantum interference devices (SQUIDs) in cavity QED. In this approach, the two lowest levels of a SQUID represent the two logical states of a qubit while a higher-energy intermediate level serves the gate manipulation. Our method operates essentially by creating a single photon through one of the control SQUIDs and then performing an arbitrary unitary transformation on the target SQUID with the assistance of the cavity photon. In addition, we show that the method can be applied to implement an n-qubit controlled-U gate with atomic qubits in cavitymore » QED.« less
  • An approach for performing a local measurement on a set of complete n-qubit maximally entangled states via cavity QED is presented. The method operates essentially by creating a single photon in the cavity through one qubit and then performing a joint multiqubit phase shift on the remaining qubits with the assistance of the photon. It is shown that for three-level qubit systems, a complete set of 2{sup n} n-qubit maximally entangled states can be measured simultaneously, deterministic and independent of the number of qubits. Hence, the method is very efficient for realizing multiqubit GHZ-state measurement which is important to quantummore » information processing and communication.« less
  • A scheme for implementing a three-qubit Toffoli gate with atoms sent through a microwave cavity is proposed by choosing nonidentical coupling constants between the atoms and cavity. The scheme can be generalized to implement an N-qubit Toffoli gate and the gating time does not change with an increase of the number of qubits.