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Tan’s two-body contact across the superfluid transition of a planar Bose gas

Abstract : Tan's contact is a quantity that unifies many different properties of a low-temperature gas with short-range interactions, from its momentum distribution to its spatial two-body correlation function. Here, we use a Ramsey interferometric method to realize experimentally the thermodynamic definition of the two-body contact, i.e., the change of the internal energy in a small modification of the scattering length. Our measurements are performed on a uniform two-dimensional Bose gas of 87Rb atoms across the Berezinskii-Kosterlitz-Thouless superfluid transition. They connect well to the theoretical predictions in the limiting cases of a strongly degenerate fluid and of a normal gas. They also provide the variation of this key quantity in the critical region, where further theoretical efforts are needed to account for our findings.
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Contributor : Gestionnaire Hal-Su <>
Submitted on : Monday, February 8, 2021 - 12:17:52 PM
Last modification on : Tuesday, February 9, 2021 - 3:28:59 AM


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Y.-Q. Zou, B. Bakkali-Hassani, C. Maury, É. Le Cerf, S. Nascimbene, et al.. Tan’s two-body contact across the superfluid transition of a planar Bose gas. Nature Communications, Nature Publishing Group, 2021, 12 (1), pp.760. ⟨10.1038/s41467-020-20647-6⟩. ⟨hal-03134440⟩



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