| Until recently, coherent phase slips were clearly observed only in qubits consisting of a few Josephson junctions. Similar observations in nanowires or multi-junction arrays were hampered by extrinsic effects. These difficulties were circumvented in a recent spectroscopic experiment with a circuit dubbed Fluxonium. Observation of the rare quantum phase slips in an array of N=43 "strong" Josephson junctions was achieved due to their interference with the phase slips in a single "weak" one. This talk presents theory of the Fluxonium, along with the experimental evidence of the Aharonov-Casher effect in the coherent phase slips interference. |
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