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Q: Fachverband Quantenoptik und Photonik

Q 64: Poster – Ultra-cold atoms, ions and BEC (joint session A/Q)

Q 64.11: Poster

Thursday, March 5, 2026, 17:00–19:00, Philo 1. OG

An Atomtronic Toolbox for Josephson Physics — •Florian Binoth, Kaih T. Mitchell, Erik Bernhart, Jan Gerhardt, Marvin Röhrle, and Herwig Ott — Department of Physics and Research Center OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany

We present an atomtronic toolbox to study quantum transport phenomena and quantum scattering problems using Bose-Einstein condensates (BECs) in spatially and temporally modulated optical potential landscapes. Our platform generates arbitrary optical potentials with a multi-axis acousto-optical deflector and a digital micromirror device. Additionally, we are developing the implementation of a novel sub-wavelength dark-state barrier using a pair of resonant Raman beams, with differing transverse modes, projected onto the atoms through an in-vacuum objective lens. The atoms are imaged using a multi-directional absorption imaging system and a scanning electron microscope with high spatial resolution.

This apparatus allows us to investigate atomtronic superconducting Josephson junctions, constructed by introducing a tunnelling barrier into a tube-shaped BEC. With an appropriate combination of AC and DC driving, the current-voltage curve of the device shows discrete Shapiro steps, that have previously been demonstrated in solid-state superconductors and form the Josephson voltage standard. We investigate the microscopic origins of this behaviour and demonstrate that in our quantum gas platform they directly connected to phonon emission and vortex dynamics.

Keywords: Bose-Einstein Condensate; Atomtronics; Josephson Physics; Shapiro Steps; Superconductivity