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A: Fachverband Atomphysik
A 1: Ultra-cold Atoms, Ions and BEC I (joint session A/Q)
A 1.4: Vortrag
Montag, 11. März 2024, 12:00–12:15, HS 1010
Shapiro steps in driven atomic Josephson junctions — •Vijay Singh1, Juan Polo1, Ludwig Mathey2, and Luigi Amico1 — 1Quantum Research Centre, Technology Innovation Institute, Abu Dhabi, UAE — 2Zentrum für Optische Quantentechnologien and Institut für Quantenphysik, Universität Hamburg, 22761 Hamburg, Germany
We study driven atomic Josephson junctions realized by coupling two two-dimensional atomic clouds with a tunneling barrier. By moving the barrier at a constant velocity, dc and ac Josephson regimes are characterized by a zero and nonzero atomic density difference across the junction, respectively. Here, we monitor the dynamics resulting in the system when, in addition to the above constant velocity protocol, the position of the barrier is periodically driven. We demonstrate that the time-averaged particle imbalance features a step-like behavior that is the analog of Shapiro steps observed in driven superconducting Josephson junctions. The underlying dynamics reveals an intriguing interplay of the vortex and phonon excitations, where Shapiro steps are induced via suppression of vortex growth. We study the system with a classical-field dynamics method, and benchmark our findings with a driven circuit dynamics.
Keywords: Atomic Josephson junction; Driven dynamics; Shapiro steps; Vortex-induced dissipation; Bose-Einstein condensate