Silent Phase Qubit Based on d-Wave Josephson Junctions

TL;DR

This paper introduces a new flux qubit design using YBCO grain boundary junctions that is inherently protected from external flux fluctuations, with proposed experiments to observe quantum phenomena.

Contribution

The paper presents a novel silent phase qubit leveraging d-Wave Josephson junctions with enhanced stability against external perturbations.

Findings

Design and fabrication of the qubit demonstrated.

Theoretical estimates of decoherence due to flux fluctuations.

Proposed experiments to observe quantum tunneling and Rabi oscillations.

Abstract

We report on design and fabrication of a new type of flux qubit that capitalizes on intrinsic properties of submicron YBCO grain boundary junctions. The operating point is protected from the fluctuations of the external fields, already on the classical level; the effects of external perturbations are absent, to the second or third order, depending on the character of the coupling. We propose an experiment to observe quantum tunneling and Rabi oscillations in the qubit. Estimate of the decoherence due to fluctuations of the external flux is presented.