Reading-out the state of a flux qubit by Josephson transmission line solitons

TL;DR

This paper proposes a method to read out the state of a Josephson flux qubit by analyzing soliton time delays in Josephson transmission lines, considering dissipation and jitter for practical measurement efficiency.

Contribution

It introduces a novel qubit read-out technique using soliton time delays in JTLs within RSFQ technology, accounting for dissipation and jitter effects.

Findings

Estimates of measurement time and efficiency under experimental conditions

Analysis of dissipative and jitter effects on soliton-based read-out

Validation of the method's feasibility for quantum measurement

Abstract

We describe the read-out process of the state of a Josephson flux qubit via solitons in Josephson transmission lines (JTL) as they are in use in the standard rapid single flux quantum (RSFQ) technology. We consider the situation where the information about the state of the qubit is stored in the time delay of the soliton. We analyze dissipative underdamped JTLs, take into account their jitter, and provide estimates of the measuring time and efficiency of the measurement for relevant experimental parameters.