PRX Quantum (May 2021)

Large Dispersive Interaction between a CMOS Double Quantum Dot and Microwave Photons

  • David J. Ibberson,
  • Theodor Lundberg,
  • James A. Haigh,
  • Louis Hutin,
  • Benoit Bertrand,
  • Sylvain Barraud,
  • Chang-Min Lee,
  • Nadia A. Stelmashenko,
  • Giovanni A. Oakes,
  • Laurence Cochrane,
  • Jason W.A. Robinson,
  • Maud Vinet,
  • M. Fernando Gonzalez-Zalba,
  • Lisa A. Ibberson

DOI
https://doi.org/10.1103/PRXQuantum.2.020315
Journal volume & issue
Vol. 2, no. 2
p. 020315

Abstract

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We report fast charge-state readout of a double quantum dot in a CMOS split-gate silicon nanowire transistor via the large dispersive interaction with microwave photons in a lumped-element resonator formed by hybrid integration with a superconducting inductor. We achieve a coupling rate g_{0}/(2π)=204±2MHz by exploiting the large interdot gate lever arm of an asymmetric split-gate device, α=0.72, and by inductively coupling to the resonator to increase its impedance, Z_{r}=560Ω. In the dispersive regime, the large coupling strength at the double quantum-dot hybridization point produces a frequency shift comparable to the resonator linewidth, the optimal setting for maximum state visibility. We exploit this regime to demonstrate rapid dispersive readout of the charge degree of freedom, with a SNR of 3.3 in 50 ns. In the resonant regime, the fast charge decoherence rate precludes reaching the strong coupling regime, but we show a clear route to spin-photon circuit quantum electrodynamics using hybrid CMOS systems.