Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 43: Quantum gases (Bosons) (joint session A/Q)

Q 43.3: Talk

Thursday, March 14, 2019, 11:00–11:15, S HS 1 Physik

Scale-invariant dynamics of an interacting 2D Bose gas — •Raphaël Saint-Jalm, Patricia Christina Marques Castilho, Édouard Le Cerf, Jean-Loup Ville, Brice Bakkali-Hassani, Sylvain Nascimbène, Jean Dalibard, and Jérôme Beugnon — Laboratoire Kastler Brossel, Collège de France, CNRS, ENS-PSL University, Sorbonne Université, 11 place Marcelin Berthelot, 75005 Paris, France

The dynamics of an interacting many-body system is usually difficult to predict fully, but some of its features can be captured if the system has underlying symmetries such as scale invariance. Here we study the dynamics of a 2D cloud of ultracold Rubidium atoms in a harmonic potential. The many-body Hamiltonian of such a system has an exact SO(2,1) symmetry and exhibits scale-invariant properties. We produce an initial cloud strongly out of equilibrium with a uniform density and a tunable shape, and observe this scale-invariant dynamics. Moreover, in the Thomas-Fermi limit where the system can be described by hydrodynamic equations, we demonstrate an additional scale invariance. We also report on the observation of particular shapes whose evolution is periodic, which we attribute to breathers of the 2D Gross-Pitaevskii equation.