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Résumé |
In a dilute gas, Tan's contact relate the thermodynamics to the short distance properties of quantum
many-body systems. Recently, the contact of a Bose gas confined in a plane has been measured in a
broad temperature range, from the normal to the superfluid phase, and across the Berezinskii-Kosterlitz-
Thouless transition. We show that the contact of this quasi-2D system can be obtained from the universal
equation of state of a two-dimensional Bose gas. We compute the contact using the functional
renormalisation group, and find a remarkable agreement with experiment. |
