Fast High-Fidelity Single-Shot Readout of Spins in Silicon Using a Single-Electron Box
Giovanni A. Oakes, Virginia N. Ciriano-Tejel, D. F. Wise, Michael A. Fogarty, Theodor Lundberg, C. Lainé, Simon Schaal, Frederico Martins, D. J. Ibberson, Louis Hutin, Benoît Bertrand, N. A. Stelmashenko, J. W. A. Robinson, Lisa Ibberson, Ayat K. Hashim, Irfan Siddiqi, A. Lee, M. Vinet, Charles G. Smith, John J. L. Morton, M. Fernando González-Zalba
Abstract
Three key metrics for readout systems in quantum processors are measurement\nspeed, fidelity and footprint. Fast high-fidelity readout enables mid-circuit\nmeasurements, a necessary feature for many dynamic algorithms and quantum error\ncorrection, while a small footprint facilitates the design of scalable,\nhighly-connected architectures with the associated increase in computing\nperformance. Here, we present two complementary demonstrations of fast\nhigh-fidelity single-shot readout of spins in silicon quantum dots using a\ncompact, dispersive charge sensor: a radio-frequency single-electron box. The\nsensor, despite requiring fewer electrodes than conventional detectors,\nperforms at the state-of-the-art achieving spin read-out fidelity of 99.2% in\nless than 6 $\\mu$s. We demonstrate that low-loss high-impedance resonators,\nhighly coupled to the sensing dot, in conjunction with Josephson parametric\namplification are instrumental in achieving optimal performance. We quantify\nthe benefit of Pauli spin blockade over spin-dependent tunneling to a\nreservoir, as the spin-to-charge conversion mechanism in these readout schemes.\nOur results place dispersive charge sensing at the forefront of readout\nmethodologies for scalable semiconductor spin-based quantum processors.\n