Letter abstract

Nature Physics 5, 95 - 99 (2009)
Published online: 7 December 2008 | doi:10.1038/nphys1153

Subject Categories: Atomic and molecular physics | Quantum physics

A millisecond quantum memory for scalable quantum networks

Bo Zhao1,4, Yu-Ao Chen1,2,4, Xiao-Hui Bao1,2, Thorsten Strassel1, Chih-Sung Chuu1, Xian-Min Jin2, Jörg Schmiedmayer3, Zhen-Sheng Yuan1,2, Shuai Chen1 & Jian-Wei Pan1,2


Scalable quantum-information processing requires the capability of storing quantum states1, 2. In particular, a long-lived storable and retrievable quantum memory for single excitations is of key importance to long-distance quantum communication with atomic ensembles and linear optics3, 4, 5, 6, 7. Although atomic memories for classical light8 and continuous variables9 have been demonstrated with millisecond storage time, lifetimes of only around 10 mus have been reported for quantum memories storing single excitations10, 11, 12, 13. Here we present an experimental investigation into extending the storage time of quantum memory for single excitations. We identify and isolate distinct mechanisms responsible for the decoherence of spin waves in atomic-ensemble-based quantum memories. By exploiting magnetic-field-insensitive states—so-called clock states—and generating a long-wavelength spin wave to suppress dephasing, we succeed in extending the storage time of the quantum memory to 1 ms. Our result represents an important advance towards long-distance quantum communication and should provide a realistic approach to large-scale quantum information processing.

  1. Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg, Germany
  2. Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
  3. Atominstitut der Österreichischen Universitäten, TU-Wien, A-1020 Vienna, Austria
  4. These authors contributed equally to this work

Correspondence to: Yu-Ao Chen1,2,4 e-mail: yuaochen@ustc.edu.cn

Correspondence to: Jian-Wei Pan1,2 e-mail: jian-wei.pan@physi.uni-heidelberg.de

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