Low-bandwidth control scheme for an oscillator stabilized Josephson qubit

TL;DR

This paper presents a low-bandwidth control scheme for an oscillator-stabilized Josephson qubit, enabling robust quantum operations through nearly adiabatic flux pulses and coupling to a transmission line.

Contribution

It introduces a novel Josephson circuit that uses low-bandwidth flux pulses and transmission line coupling to stabilize quantum rotations against flux noise.

Findings

High-visibility Ramsey fringes achieved

Rotation angle stabilization via flux noise mitigation

Visibility depends on flux portal width and ramp rate

Abstract

We introduce a new Josephson junction circuit for which quantum operations are realized by low-bandwidth, nearly adiabatic magnetic-flux pulses. Coupling to the fundamental mode of a superconducting transmission line permits a stabilization of the rotation angle of the quantum operation against flux noise. A complete scheme for one-qubit rotations, and high-visibility Ramsey-fringe oscillations, is given. We show that high visibility depends on passing through a portal in the space of applied fluxes, where the width of the portal is proportional to the ramp-up rate of the flux pulse.