Supercurrent tuning of the Josephson coupling energy

Abstract

The ability to non-dissipatively tune the Josephson coupling energy of Josephson junctions is a useful tool in frequency-tunable qubits. This is typically done by threading magnetic flux through two junctions connected in a loop, a geometry that exposes the qubit to magnetic environmental noise. In this paper, we show that by biasing a junction with supercurrent from a separate pair of superconducting leads coupled to the device, the Josephson energy can be tuned without the need for a flux loop. Our multiterminal device may enable the realization of a frequency-tunable qubit with greatly reduced susceptibility to flux noise.