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Phys. Rev. A 79, 043631 (2009) [5 pages]

Amplification of fluctuations in a spinor Bose-Einstein condensate

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S. R. Leslie1,*, J. Guzman1,2, M. Vengalattore1, Jay D. Sau1, Marvin L. Cohen1,2, and D. M. Stamper-Kurn1,2
1Department of Physics, University of California-Berkeley, Berkeley, California 94720, USA
2Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

Received 9 June 2008; revised 8 August 2008; published 28 April 2009

Dynamical instabilities in a 87Rb F=1 spinor Bose-Einstein condensate are used as a parametric amplifier of quantum spin fluctuations. We demonstrate the spectrum of this amplifier to be tunable, in quantitative agreement with theory. We quantify the microscopic spin fluctuations of the initially paramagnetic condensate by applying this amplifier and measuring the resulting macroscopic magnetization. The variance of these fluctuations agrees with predictions of a beyond-mean-field theory. This spin amplifier is thus shown to be nearly quantum limited at a gain as high as 30 dB.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.79.043631
DOI:
10.1103/PhysRevA.79.043631
PACS:
03.75.Mn, 05.30.Jp, 42.50.−p, 75.45.+j

*sleslie@berkeley.edu