Abstract

We report a large coupling rate, g/2π = 183 MHz, between the charge state of a double quantum dot in a CMOS split-gate silicon nanowire transistor and microwave photons in a lumped-element resonator, which is formed by wire-bonding to a superconducting inductor fabricated on a separate chip. We enhance the coupling by exploiting the large interdot lever arm of an asymmetric split-gate device, α =0.72, and by inductively coupling to the resonator to increase its impedance, Z = 560 Ω. In the dispersive regime, the large coupling strength at the DQD hybridisation point produces a frequency shift comparable to the resonator linewidth, the optimal setting for maximum state visibility. We exploit this regime to demonstrate rapid gate-based readout of the charge degree of freedom, with an 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.

References

1) https://arxiv.org/abs/2004.00334

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