Optimal cloning of mixed Gaussian states
- University of Nijmegen, Toernooiveld 1, Postbus 9010, 6500 GL Nijmegen (Netherlands)
- National Inatitute of Informatics, 2-1-2, Hitotsubashi, Chiyoda-ku, Tokyo, 101-8430 (Japan)
We construct the optimal one to two cloning transformation for the family of displaced thermal equilibrium states of a harmonic oscillator, with a fixed and known temperature. The transformation is Gaussian and it is optimal with respect to the figure of merit based on the joint output state and norm distance. The proof of the result is based on the equivalence between the optimal cloning problem and that of optimal amplification of Gaussian states which is then reduced to an optimization problem for diagonal states of a quantum oscillator. A key concept in finding the optimum is that of stochastic ordering which plays a similar role in the purely classical problem of Gaussian cloning. The result is then extended to the case of n to m cloning of mixed Gaussian states.
- OSTI ID:
- 20857658
- Journal Information:
- Physical Review. A, Vol. 74, Issue 3; Other Information: DOI: 10.1103/PhysRevA.74.032305; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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