Virial theorem for confined universal Fermi gases

J. E. Thomas

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arXiv · 0803.1647

Virial theorem for confined universal Fermi gases

J. E. Thomas

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Abstract

Optically-trapped two-component Fermi gases near a broad Feshbach resonance exhibit universal thermodynamics, where the properties of the gas are independent of the details of the two-body scattering interactions. We present a global proof that such a universal gas obeys the virial theorem for {\it any} trapping potential $U$ and any spin mixture, without assuming either the local density approximation or harmonic confinement. The total energy of the gas is given in scale invariant form by $E=<ε\partial U/\partialε>$, where $ε$ is an {\it arbitrary} energy scale in terms of which all length and energy scales that appear in the confining potential are written. This result enables model-independent energy measurement in traps that are anharmonic as well as anisotropic by observing only the cloud profile, and provides a consistency check for many-body calculations in the universal regime.

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J. E. Thomas. 2008-03-11. Virial theorem for confined universal Fermi gases. https://arxiv.org/abs/0803.1647

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