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Analysis of measurement errors for a superconducting phase qubit

Qin Zhang·Abraham G. Kofman·John M. Martinis·Alexander N. Korotkov
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Abstract

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 Schrödinger equation.

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Qin Zhang, Abraham G. Kofman, John M. Martinis, Alexander N. Korotkov. 2006-07-14. Analysis of measurement errors for a superconducting phase qubit. https://doi.org/10.1103/physrevb.74.214518

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