Supercurrent tuning of the Josephson coupling energy

TL;DR

This paper demonstrates a method to tune the Josephson coupling energy in superconducting devices using supercurrent biasing, avoiding flux loops and reducing magnetic noise susceptibility in qubits.

Contribution

It introduces a multiterminal device that allows non-dissipative tuning of Josephson energy without flux loops, enhancing qubit stability.

Findings

Supercurrent biasing effectively tunes Josephson energy.

Reduced flux noise susceptibility in qubits.

Potential for improved frequency-tunable qubits.

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.