Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 16: Bosonic Quantum Gases III (joint session Q/A)

Q 16.2: Talk

Tuesday, March 12, 2024, 11:15–11:30, Aula

Supersolidity in a driven quantum gas — •Nikolas Liebster¹, Marius Sparn¹, Elinor Kath¹, Keisuke Fujii², Sarah Görlitz², Tilman Enss², Helmut Strobel¹, and Markus Oberthaler¹ — ¹Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany — ²Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany

Driven systems are of fundamental scientific interest, as they can display properties that are radically different from similar systems at equilibrium. However, systems out of equilibrium are difficult to describe theoretically, as they are inherently time-dependent and deeply nonlinear. This makes the study of such systems an ideal task for quantum field simulators, in which complex dynamics emerge naturally and can be probed experimentally. Here, we demonstrate the emergence of supersolidity in a driven, two-dimensional superfluid, that only has contact interactions. The self-stabilized system is characterized by simultaneously broken translational and U(1) gauge symmetry, and emerges as a result of large occupations of phononic modes due to driving. We characterize the state by observing collective modes of the lattice as well as lattice phonon propagation. We also show that the system maintains phase rigidity, a key property of superfluidity. This work introduces a novel type of supersolid that is readily experimentally accessible, and establishes a conceptual framework for describing elementary excitations of driven systems.

Keywords: Superfluids; Pattern Formation; Bose Einstein Condensate; Driven Systems