Probing the local rapidity distribution of a 1D Bose gas
After relaxation, an integrable quantum system, in particular a one-dimensional gas of bosons, is characterized by the rapidities distribution, a quantity preserved throughout the dynamics. The rapidities distribution is nothing else than the asymptotic momentum distribution of particles after a one-dimensional expansion of the system. This definition is directly linked to an experimental procedure allowing to access this quantity. We can also study the different stages of the expansion by using the Generalized HydroDynamics theory, an emerging hydrodynamic theory applicable to quantum integrable systems. In our experiment, 87Rb atoms are trapped by an atom chip to reach the one-dimensional regime. A spatial selection tool has been integrated in our setup allowing to locally probe the rapidity distribution by performing one-dimensional expansions of selected parts of the cloud. I will present the comparisons between the experimental expansions with the predicted profiles by Generalized HydroDynamics [1]. I will also present you some preliminary results about new protocols that we implemented thanks to the spatial selection tool in order to test the Generalized Hydrodynamics theory with initial out-of equilibrium 1D Bose gas.
[1] L. Dubois, G. Thémèze, J. Dubail and I. Bouchoule, arXiv: 2312.15344