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Q: Fachverband Quantenoptik und Photonik
Q 33: Cavity QED, QED, and Spin-Boson Systems I
Q 33.3: Talk
Wednesday, March 4, 2026, 15:00–15:15, P 4
Condensate dynamics in higher bands in a Cavity-BEC system — •Hannah Kleine-Pollmann1,2 and Ludwig Mathey1,2,3 — 1Institut für Quantenphysik, Universität Hamburg, 22761 Hamburg, Germany — 2Zentrum für Optische Quantentechnologien, Universität Hamburg, 22761 Hamburg, Germany — 3The Hamburg Centre for Ultrafast Imaging, 22761 Hamburg, Germany
We investigate the behaviour of a Bose-Einstein condensate in higher Bloch bands in a driven-dissipative Cavity-BEC system. The condensate is trapped in a bipartite s-px-py-lattice, with a tunable energy offset. This enables a controlled population transfer from the s-orbital to the nearly degenerate px- and py-orbitals. The system forms a chiral ground state of the form px ± i py with staggered orbital currents. By increasing the transverse pump strength, we drive the system into the superradiant phase, resulting in a self-organized, symmetry-broken sublattice pattern where the chiral order is directly coupled to the superradiant structure. Using Truncated Wigner simulations and complementary mean-field analysis, we map out the phase diagram. Our results show that higher-band condensates coupled to a cavity provide a promising platform for engineering non-trivial orbital order and topological superfluid phases in quantum optical many-body systems.
Keywords: Neutral atoms; Superradiant phase transition; Atom-cavity system; BEC; higher bands