Fast Quantum Nondemolition Readout by Parametric Modulation of Longitudinal Qubit-Oscillator Interaction

Nicolas Didier, Jérôme Bourassa, and Alexandre Blais

Phys. Rev. Lett. 115, 203601 – Published 9 November 2015

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.

Received 27 April 2015

DOI:https://doi.org/10.1103/PhysRevLett.115.203601

Authors & Affiliations

Nicolas Didier^1,2, Jérôme Bourassa³, and Alexandre Blais^2,4

¹Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada
²Départment de Physique, Université de Sherbrooke, 2500 boulevard de l’Université, Sherbrooke, Québec J1K 2R1, Canada
³Cégep de Granby, 235, rue Saint-Jacques, Granby, Québec J2G 9H7, Canada
⁴Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada