Developing fast, accurate and scalable techniques for quantum state readout is an active area in semiconductor-based quantum computing. Here, we present results on dispersive sensing of silicon corner state quantum dots coupled to lumped-element electrical resonators via the gate. The gate capacitance of the quantum device is configured in parallel with a superconducting spiral inductor resulting in resonators with loaded Q-factors in the 400-800 range. For a resonator operating at 330 MHz, we achieve a charge sensitivity of 7.7 μe/Hz and, when operating at 616 MHz, we get 1.3 μe/Hz. We perform a parametric study of the resonator to reveal its optimal operation points and perform a circuit analysis to determine the best resonator design. The results place gate-based sensing at par with the best reported radio-frequency single-electron transistor sensitivities while providing a fast and compact method for quantum state readout.
@article{arxiv.1801.09759,
title = {Radio-frequency capacitive gate-based sensing},
author = {Imtiaz Ahmed and James A. Haigh and Simon Schaal and Sylvain Barraud and Yi Zhu and Chang-min Lee and Mario Amado and Jason W. A. Robinson and Alessandro Rossi and John J. L. Morton and M. Fernando Gonzalez-Zalba},
journal= {arXiv preprint arXiv:1801.09759},
year = {2021}
}