Condensed Matter Physics Seminar

Dr Alexander Zorin, Physikalisch-Technische Bundesanstalt, Germany

Thursday 20 February 2014, 1500-1600
C1 Physics Building

Josephson period-doubling bifurcation circuits

Due to strong nonlinearity of Josephson inductance, superconducting circuits can exhibit remarkable effects. These circuits can bifurcate, an effect recently applied to quantum measurements using the so-called Josephson bifurcation amplifier (JBA). Previously the system was shown bifurcates from a single oscillation to a bistable regime at the same frequency. We propose a circuit enabling a regime of period doubling bifurcation, in which the circuit is driven at a double frequency whereas a large output signal appears at the base resonance frequency. We show how this PDB circuit can be used for detecting small electric signals including readout of Josephson qubits.