Multiplexed dispersive readout of superconducting phase qubits*

A dispersive readout scheme is being developed for superconducting phase qubits. By inductively coupling to a LC resonator, the measured state of the qubit (left or right side of the potential well) can be read out as a shift of the resonance frequency. Compared to our current SQUID readout, this method eliminates the generation of quasiparticles, increases the reliability by reducing the junction count per qubit from 4 to 1, and reduces the chip wire count since the readout can be frequency multiplexed.