title: Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator.
abstract: We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing.
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-41296 Gothenburg, Sweden.
authors.forename: Philip
authors.identifier: 0000-0002-8553-3353
authors.initials: P
authors.lastname: Krantz
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-41296 Gothenburg, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bengtsson
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-41296 Gothenburg, Sweden.
authors.forename: Michaël
authors.initials: M
authors.lastname: Simoen
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Gustavsson
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-41296 Gothenburg, Sweden.
authors.forename: Vitaly
authors.initials: V
authors.lastname: Shumeiko
authors.affiliation: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.|MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA.
authors.forename: W D
authors.initials: WD
authors.lastname: Oliver
authors.affiliation: Institute of Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: C M
authors.initials: CM
authors.lastname: Wilson
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-41296 Gothenburg, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Delsing
authors.affiliation: Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-41296 Gothenburg, Sweden.
authors.forename: Jonas
authors.identifier: 0000-0003-4521-710X
authors.initials: J
authors.lastname: Bylander
mesh_terms: D000669:Amplifiers, Electronic; D003198:Computer Simulation; D004553:Electric Conductivity; D011789:Quantum Theory