Universal contact for a Tonks-Girardeau gas at finite temperature

Abstract

We determine the finite-temperature momentum distribution of a strongly interacting 1D Bose gas in the Tonks-Girardeau (impenetrable-boson) limit under harmonic confinement, and explore its universal properties associated to the scale invariance of the model. We show that, at difference from the unitary Fermi gas in three dimensions, the weight of its large-momentum tails -- given by the Tan's contact -- increase with temperature, and calculate the high-temperature universal second contact coefficient using a virial expansion.