We analyze several mechanisms leading to errors in a course of measurement of a superconducting flux-biased phase qubit. Insufficiently long measurement pulse may lead to nonadiabatic transitions between qubit states ∣1> and ∣0>, before tunneling through a reduced barrier is supposed to distinguish the qubit states. Finite (though large) ratio of tunneling rates for these states leads to incomplete discrimination between ∣1> and ∣0>. Insufficiently fast energy relaxation after the tunneling of state ∣1> may cause the repopulation of the quantum well in which only the state ∣0> is supposed to remain. We analyze these types of measurement errors using analytical approaches as well as numerical solution of the time-dependent Schr\"{o}dinger equation.
@article{arxiv.cond-mat/0607385,
title = {Analysis of measurement errors for a superconducting phase qubit},
author = {Qin Zhang and Abraham G. Kofman and John M. Martinis and Alexander N. Korotkov},
journal= {arXiv preprint arXiv:cond-mat/0607385},
year = {2015}
}