Common flux qubit readout schemes are qubit dominated, meaning they measure in the energy eigenbasis of the qubit. For various applications meausrements in a basis different from the energy eigenbasis are required. Here we present an indirect measurement protocol, which is detector dominated instead of qubit dominated, yielding a projective measurements in the persistent current basis for arbitrary bias points. We show that with our setup it is possible to perform a quantum nondemolition measurement (QND) in the persistent current basis at all flux bias points with fidelities reaching almost 100%.
@article{arxiv.1904.13157,
title = {Flux Qubit Readout in the Persistent Current Basis at arbitrary Bias Points},
author = {Marius Schöndorf and Adrian Lupascu and Frank K. Wilhelm},
journal= {arXiv preprint arXiv:1904.13157},
year = {2020}
}