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Experimental demonstration of quantum teleportation of a squeezed state

Nobuyuki Takei, Takao Aoki, Satoshi Koike, Ken-ichiro Yoshino, Kentaro Wakui, Hidehiro Yonezawa, Takuji Hiraoka, Jun Mizuno, Masahiro Takeoka, Masashi Ban, and Akira Furusawa
Phys. Rev. A 72, 042304 – Published 3 October 2005
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  • INTRODUCTION
  • A SQUEEZED THERMAL STATE
  • TELEPORTATION PROCEDURE
  • RESULTS
  • DISCUSSION
  • CONCLUSION
  • ACKNOWLEDGEMENTS
    • References

    Abstract

    Quantum teleportation of a squeezed state is demonstrated experimentally. Due to some inevitable losses in experiments, a squeezed vacuum necessarily becomes a mixed state which is no longer a minimum uncertainty state. We establish an operational method of evaluation for quantum teleportation of such a state using fidelity and discuss the classical limit for the state. The measured fidelity for the input state is 0.85±0.05, which is higher than the classical case of 0.73±0.04. We also verify that the teleportation process operates properly for the nonclassical state input and its squeezed variance is certainly transferred through the process. We observe the smaller variance of the teleported squeezed state than that for the vacuum state input.

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    • Received 7 November 2003

    DOI:https://doi.org/10.1103/PhysRevA.72.042304

    ©2005 American Physical Society

    Authors & Affiliations

    Nobuyuki Takei1,2, Takao Aoki1,2, Satoshi Koike1, Ken-ichiro Yoshino1, Kentaro Wakui1,2,3, Hidehiro Yonezawa1,2, Takuji Hiraoka1, Jun Mizuno2,3, Masahiro Takeoka2,3, Masashi Ban2,4, and Akira Furusawa1,2

    • 1Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
    • 2CREST, Japan Science and Technology (JST) Agency, 1-9-9 Yaesu, Chuo-ku, Tokyo 103-0028, Japan
    • 3National Institute of Information and Communication Technology (NICT), 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan
    • 4Advanced Research Laboratory, Hitachi Ltd, 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan

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    Issue

    Vol. 72, Iss. 4 — October 2005

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    • Figure 1
      Figure 1
      Schematic setup of the experiment for quantum teleportation of a squeezed state. OPOs represent optical parametric oscillators. AM and PM denote amplitude and phase modulators. LOs are local oscillators for homodyne detection. The ellipses indicate the squeezed quadrature of each beam. All beam splitters except 99-1 BS are 50-50 beam splitters. Symbols and abbreviations are defined in the text.Reuse & Permissions
    • Figure 2
      Figure 2
      The measurement results on the input squeezed state recorded by the Ap homodyne detector with Alice’s 50-50 BS removed. Trace (i) shows the corresponding vacuum noise level; trace (ii) is the variance of the squeezed state with the LO phase scanned; traces (iii) and (iv) are the minimum and the maximum noise levels with the LO phase locked. The measurement frequency is 1MHz, and the resolution and video bandwidth are 30kHz and 300Hz, respectively. All traces except for (ii) are averaged ten times.Reuse & Permissions
    • Figure 3
      Figure 3
      The measurement results on the output states recorded by Victor in the x quadrature, where (a) is the classical teleportation without the EPR beams, (b) the teleportation with the EPR beams, (i) the corresponding shot noise level, (ii) the vacuum state input, (iii) the squeezed state input with the phase of the input state scanned, and (iv) the minimum noise levels with the phase of the input state locked. The measurement conditions are the same as for Fig. 2.Reuse & Permissions
    • Figure 4
      Figure 4
      The calculated fidelity FsqC between the input and the output. (a) The dependence of FsqC on the variance coth(β∕2) with the fixed antisqueezing e+2r of 5.06dB. The measured value of the fidelity FsqQ is plotted as the cross “×” at coth(β∕2) of 2.39dB. (b) The dependence of FsqC on the antisqueezing e+2r with the fixed variance coth(β∕2) of 2.39dB. The measured value of the fidelity FsqQ is plotted as the cross “×” at e+2r of 5.06dB.Reuse & Permissions
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