Approaching ultrastrong coupling in transmon circuit QED using a high-impedance resonator

Journal article (2017)

Authors

S.J. Bosman QN/Steele Lab - AS
M.F. Gely QN/Steele Lab - AS
Vibhor Singh Indian Institute of Science
D. Bothner QN/Steele Lab - AS
Andres Castellanos-Gomez Instituto de Ciencia de Materiales de Madrid (ICMM)
G.A. Steele QN/Steele Lab - AS
Research Group
QN/Steele Lab (AS) (TU Delft)
Copyright: © 2017 S.J. Bosman, M.F. Gely, Vibhor Singh, D. Bothner, Andres Castellanos-Gomez, G.A. Steele
DOI: https://doi.org/10.1103/PhysRevB.95.224515
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Published Date

29-06-2017

Language

English

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Faculty

Applied Sciences

Department

QN/Quantum Nanoscience

Research Group

QN/Steele Lab

Abstract

In this experiment, we couple a superconducting transmon qubit to a high-impedance 645Ω microwave resonator. Doing so leads to a large qubit-resonator coupling rate g, measured through a large vacuum Rabi splitting of 2g≃910 MHz. The coupling is a significant fraction of the qubit and resonator oscillation frequencies ω, placing our system close to the ultrastrong coupling regime (g=g/ω=0.071 on resonance). Combining this setup with a vacuum-gap transmon architecture shows the potential of reaching deep into the ultrastrong coupling g∼0.45 with transmon qubits.