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Q: Fachverband Quantenoptik und Photonik
Q 36: Ultra-cold Atoms, Ions and BEC III (joint session A/Q)
Q 36.5: Vortrag
Mittwoch, 12. März 2025, 12:15–12:30, KlHS Mathe
Controlled Dynamical Tunneling in Bichromatic Optical Lattices with a Parabolic Trap — •usman ali1, martin holthaus2, and torsten meier1 — 1Department of Physics, Paderborn University, Warburger Strasse 100, D-33098 Paderborn, Germany — 2Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg, Germany
We investigate dynamical tunneling of non-interacting ultracold atomic wave packets in the combined potential generated by the superposition of a one-dimensional periodic optical lattice and a parabolic trap. The parabolic lattice potential exhibits strongly localized eigenstates in the regime where the curvature of the periodic lattice exceeds the bandwidth of the uniform periodic lattice. The localization of these states is similar to Wannier-Stark localization in the presence of a locally static force, which gives rise to dynamics resembling Bloch oscillations. Furthermore, due to the symmetry of the parabolic lattice, these eigenstates are nearly two-fold degenerate. The tiny energy splitting between symmetry-related pairs located at opposite ends of the parabolic lattice results in tunneling times that exceed experimentally realizable time scales. We demonstrate that the inclusion of an additional weak optical lattice allows one to control the tunneling times while preserving the states. Thereby controllable dynamical tunneling is achieved, where the Bloch-oscillating wave packet dynamically tunnels between opposite ends of the weakly bichromatic parabolic optical lattice.
Keywords: Wave packet dynamics; dynamical tunneling; parabolic optical lattices; Mathieu equation; bichromatic optical lattices