Interaction-free measurements with superconducting qubits.
An interaction-free measurement protocol is described for a quantum circuit consisting of a superconducting qubit and a readout Josephson junction. By measuring the state of the qubit, one can ascertain the presence of a current pulse through the circuit at a previous time without any energy exchange between the qubit and the pulse.
Paraoanu
G S
GS
NanoScience Center and Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FIN-40014 University of Jyväskylä, Finland. paraoanu@phys.jyu.fi