title: Sisyphus effects in a microwave-excited flux-qubit resonator system.
abstract: Sisyphus amplification, familiar from quantum optics, has recently been reported as a mechanism to explain the enhanced quality factor of a classical resonant (tank) circuit coupled to a superconducting flux qubit. Here we present data from a coupled system, comprising a quantum mechanical rf SQUID (flux qubit) reactively monitored by an ultrahigh quality factor noise driven rf resonator and excited by microwaves. The system exhibits enhancement of the tank-circuit resonance, bringing it significantly closer (within 1%) to the lasing limit, than previously reported results.
authors.affiliation: Centre for Physical Electronics and Quantum Technology, School of Engineering and Design, University of Sussex, Brighton, East Sussex BN1 9QT, United Kingdom. j.c.skinner@sussex.ac.uk
authors.forename: J C
authors.initials: JC
authors.lastname: Skinner
authors.forename: H
authors.initials: H
authors.lastname: Prance
authors.forename: P B
authors.initials: PB
authors.lastname: Stiffell
authors.forename: R J
authors.initials: RJ
authors.lastname: Prance