Microwave readout scheme for a Josephson phase qubit

摘要

We present experimental results on a microwave scheme for reading out a Josephson phase qubit.nA capacitively shunted superconducting quantum interference device u0002SQUIDu0003 is used as annonlinear resonator which is inductively coupled to the qubit. The flux state of the qubit is detectednby measuring the amplitude and phase of a microwave pulse reflected from the SQUID resonator.nBy this low-dissipative method, the qubit state measurement time is reduced to 25 u0002s, which isnmuch faster than the conventional readout performed by switching the SQUID to its nonzero dcnvoltage state. The readout scheme presented here allows for reading out multiple qubits using ansingle microwave line by employing frequency-division multiplexing. © 2010 American Institute ofnPhysics. u0004doi:10.1063/1.3533805