Hybrid quantum computation in quantum optics（混合量子光学量子计算）.pdfVIP

PHYSICAL REVIEW A 78, 022303 2008 Hybrid quantum computation in quantum optics P. van Loock,1,2,* W. J. Munro,1,3 Kae Nemoto,1 T. P. Spiller,3 T. D. Ladd,1,4 Samuel L. Braunstein,5 and G. J. Milburn6 1 National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan 2 Optical Quantum Information Theory Group, Institute of Theoretical Physics I and Max-Planck Research Group, Institute of Optics, Information and Photonics, Universität Erlangen-Nürnberg, Staudtstrasse 7/B2, 91058 Erlangen, Germany 3 Hewlett-Packard Laboratories, Filton Road, Stoke Gifford, Bristol BS34 8QZ, United Kingdom 4 Edward L. Ginzton Laboratory, Stanford University, Stanford, California 94305-4088, USA 5 Computer Science, University of York, York YO10 5DD, United Kingdom 6 Centre for Quantum Computer Technology, Department of Physics, University of Queensland, Brisbane, Australia Received 9 August 2006; revised manuscript received 4 July 2008; published 1 August 2008 We propose a hybrid quantum computing scheme where qubit degrees of freedom for computation are combined with quantum continuous variables for communication. In particular, universal two-qubit gates can be implemented deterministically through qubit-qubit communication, mediated by a continuous-variable bus mode “qubus”, without direct interaction between the qubits and without any measurement of the qubus. The key ingredients are controlled rotations of the qubus and unconditional qubus displaceme