Dynamical Stabilization of Supercurrents in a Graphene-Based Josephson Network

Josephson networks are a promising platform for harboring synthetic topological phases of matter and Floquet states. These networks have hosted Cooper multiplets–coherent transport of four or more electrons through splitting of Cooper pairs and subsequent Andreev reflections. In this talk, we demonstrate multi-junction dynamical supercurrents emerging from an engineered Josephson network. The device features three superconducting electrodes connected through graphene to a superconducting island. The dynamical supercurrents include features similar to Cooper quartets, which are robust to elevated temperatures and exhibit the expected Shapiro step quantization under microwave drive. Additionally, we observe an unexpected supercurrent mediated between adjacent contacts through the superconducting island. These experimental results are substantiated by demonstrations of dynamical stabilization in the RCSJ model of the device.