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Observation of a persistent non-equilibrium state in cold atoms

Nature Physics volume 11, pages 10091012 (2015) | Download Citation


Boltzmann noticed that his transport equation predicts special cases in which gases never reach thermal equilibrium. One example is the monopole breathe mode of atoms confined in a perfectly isotropic three-dimensional (3D) harmonic potential1. Such a complete absence of damping had not been observed in nature, and this anomaly weakened Boltzmann’s then-controversial claim to have established a microscopic, atomistic basis for thermodynamics. Only recently has non-damping of a monopole mode in lower-dimensional systems been reported in cold-atom experiments performed in highly elongated trap geometries2,3. The difficulty in generating a sufficiently spherical harmonic confinement for cold atoms has so far prevented the observation of Boltzmann’s fully 3D, isotropic case. Here, thanks to a new magnetic trap4 capable of producing near-spherical harmonic confinement for cold atoms, we report a long-delayed vindication for Boltzmann: the observation of a 3D monopole mode for which the collisional contribution to damping vanishes.

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This research was supported by the Marsico Fund and NSF grant PHY-1125844.

Author information


  1. JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA

    • D. S. Lobser
    • , A. E. S. Barentine
    • , E. A. Cornell
    •  & H. J. Lewandowski
  2. Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA

    • D. S. Lobser
    • , A. E. S. Barentine
    • , E. A. Cornell
    •  & H. J. Lewandowski


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D.S.L., A.E.S.B., E.A.C. and H.J.L. are jointly responsible for design of the experiment, analysis of data, and preparation of the manuscript. D.S.L. and A.E.S.B., in addition, collected the data.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to H. J. Lewandowski.

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