The Shapiro effect in atomchip-based bosonic Josephson junctions

Abstract

We analyze the emergence of Shapiro resonances in tunnel-coupled\nBose-Einstein condensates, realizing a bosonic Josephson junction. Our analysis\nis based on an experimentally relevant implementation using magnetic double\nwell potentials on an atomchip. In this configuration the potential bias\n(implementing the junction voltage) and the potential barrier (realizing the\nJosephson link) are intrinsically coupled. We show that the dynamically driven\nsystem exhibits significantly enhanced Shapiro resonances which will facilitate\nexperimental observation. To describe the systems response to the dynamic drive\nwe compare a single-mode Gross-Pitaevskii (GP) description, an improved\ntwo-mode (TM) model and the self-consistent multi-configurational time\ndependent Hartree for Bosons (MCTDHB) method. We show that in the case of\nsignificant atom-atom interactions or strong driving, the spatial dynamics of\nthe involved modes have to be taken into account, and only the MCTDHB method\nallows reliable predictions.\n