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

Abstract

We describe the readout process of the state of a Josephson flux qubit via solitons in Josephson transmission lines (JTLs) as they are in use in the standard rapid single flux quantum 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.