Strong-interaction effects on Shapiro step dynamics in atomic Josephson junctions

Determine whether strong interparticle interactions in ultracold Fermi superfluids affect the dynamics of Shapiro steps and the associated phase-synchronization behavior in periodically driven atomic Josephson junctions realized by periodically oscillating the position of a thin tunneling optical barrier.

Background

Shapiro steps in Josephson junctions arise from phase-locking between the junction’s intrinsic Josephson oscillations and an external drive, producing quantized plateaus in the current–voltage characteristics. While these have long been established in superconducting junctions, their controlled realization and paper in atomic systems has recently advanced, including predictions for weakly interacting Bose–Einstein condensates via periodic oscillations of a thin tunneling barrier.

In the context of ultracold Fermi superfluids, particularly near unitarity where interactions are strong, it is anticipated that interactions may enhance phase coherence and reduce decoherence associated with compressibility. However, whether and how such strong interactions modify the non-equilibrium dynamics of Shapiro steps and influence synchronization processes in driven atomic Josephson junctions remains unresolved, motivating direct investigation in strongly interacting regimes.