中国物理B ›› 2008, Vol. 17 ›› Issue (1): 49-54.doi: 10.1088/1674-1056/17/1/009

• GENERAL • 上一篇    下一篇

Cavity loss induced generation of W states

吴怀志, 杨贞标, 苏万钧, 钟志荣, 郑仕标   

  1. Department of Electronic Science and Applied Physics, Fuzhou University, Fuzhou 350002, China
  • 出版日期:2008-01-20 发布日期:2008-01-20

Cavity loss induced generation of W states

Wu Huai-Zhi(吴怀志), Yang Zhen-Biao(杨贞标), Su Wan-Jun(苏万钧), Zhong Zhi-Rong(钟志荣), and Zheng Shi-Biao(郑仕标)†   

  1. Department of Electronic Science and Applied Physics, Fuzhou University, Fuzhou 350002, China
  • Online:2008-01-20 Published:2008-01-20

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摘要： The existence of decoherence-free subspace (DFS) has been discussed widely. In this paper, we propose an alternative scheme for generating the four-atom $W$ states by manipulating DF qubits. The atoms are divided into two pairs and trapped in two separate optical cavities. Manipulation of atoms within DFS may generate a two-atom maximally entangled state in an individual cavity, which is a stable state. After driving the system out of DFS, the atoms will interact resonantly with the cavity field. The photons leaking from the cavities interfere at the beamsplitter, which destroys which-path information, and are finally detected by one of the detectors, leading to the generation of a $W$ state. In addition, the numerical simulation indicates that the fidelity of the prepared state can, for a very wide parameter regime, be very close to unity.

Abstract: The existence of decoherence-free subspace (DFS) has been discussed widely. In this paper, we propose an alternative scheme for generating the four-atom $W$ states by manipulating DF qubits. The atoms are divided into two pairs and trapped in two separate optical cavities. Manipulation of atoms within DFS may generate a two-atom maximally entangled state in an individual cavity, which is a stable state. After driving the system out of DFS, the atoms will interact resonantly with the cavity field. The photons leaking from the cavities interfere at the beamsplitter, which destroys which-path information, and are finally detected by one of the detectors, leading to the generation of a $W$ state. In addition, the numerical simulation indicates that the fidelity of the prepared state can, for a very wide parameter regime, be very close to unity.

Key words: decoherence-free subspace, leakage of photons, $W$ states

中图分类号:  (Cavity quantum electrodynamics; micromasers)

  • 42.50.Pq
03.65.Ud (Entanglement and quantum nonlocality) 03.65.Yz (Decoherence; open systems; quantum statistical methods) 03.67.Lx (Quantum computation architectures and implementations) 37.10.De (Atom cooling methods)