title: Fast Quantum Nondemolition Readout by Parametric Modulation of Longitudinal Qubit-Oscillator Interaction.
abstract: We show how to realize fast and high-fidelity quantum nondemolition qubit readout using longitudinal qubit-oscillator interaction. This is accomplished by modulating the longitudinal coupling at the cavity frequency. The qubit-oscillator interaction then acts as a qubit-state dependent drive on the cavity, a situation that is fundamentally different from the standard dispersive case. Single-mode squeezing can be exploited to exponentially increase the signal-to-noise ratio of this readout protocol. We present an implementation of this longitudinal parametric readout in circuit quantum electrodynamics and a possible multiqubit architecture.
authors.affiliation: Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada.|Départment de Physique, Université de Sherbrooke, 2500 boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Didier
authors.affiliation: Cégep de Granby, 235, rue Saint-Jacques, Granby, Québec J2G 9H7, Canada.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Bourassa
authors.affiliation: Départment de Physique, Université de Sherbrooke, 2500 boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada.|Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Blais