Flux Noise in Josephson Phase Qubits

We present a new method to measure 1=f noise in Josephson quantum bits (qubits) that yields lowfrequency spectra below 1 Hz. A comparison of the noise taken at positive and negative bias of a phase qubit shows the dominant noise source to be flux noise and not junction critical-current noise, with a magnitude similar to that measured previously in other… CONTINUE READING