High-fidelity single-shot readout for a spin qubit via an enhanced latching mechanism

作     者：Harvey-Collard, Patrick D'Anjou, Benjamin Rudolph, Martin Jacobson, N. Tobias Dominguez, Jason Eyck, Gregory A. Ten Wendt, Joel R. Pluym, Tammy Lilly, Michael P. Coish, William A. Pioro-Ladri-re, Michel Carroll, Malcolm S. 

作者机构：D-partement de Physique Institut Quantique Universit- de Sherbrooke SherbrookeQCJ1K2R1 Canada Sandia National Laboratories AlbuquerqueNM87185 United States Department of Physics McGill University Montr-alQCH3A2T8 Canada Center for Computing Research Sandia National Laboratories AlbuquerqueNM87185 United States Center for Integrated Nanotechnologies Sandia National Laboratories AlbuquerqueNM87185 United States Quantum Information Science Program Canadian Institute for Advanced Research TorontoONM5G1Z8 Canada Center for Quantum Devices Niels Bohr Institute University of Copenhagen Copenhagen2100 Denmark 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2017年

核心收录：

主　　题：Qubits 

摘      要：The readout of semiconductor spin qubits based on spin blockade is fast but suffers from a small charge signal. Previous work suggested large benefits from additional charge mapping processes, however uncertainties remain about the underlying mechanisms and achievable fidelity. In this work, we study the single-shot fidelity and limiting mechanisms for two variations of an enhanced latching readout. We achieve average single-shot readout fidelities 99:3% and 99:86% for the conventional and enhanced readout respectively, the latter being the highest to date for spin blockade. The signal amplitude is enhanced to a full one-electron signal while preserving the readout speed. Furthermore, layout constraints are relaxed because the charge sensor signal is no longer dependent on being aligned with the conventional (2;0)..(1;1) charge dipole. Silicon donor-quantum-dot qubits are used for this study, for which the dipole insensitivity substantially relaxes donor placement requirements. One of the readout variations also benefits from a parametric lifetime enhancement by replacing the spin-relaxation process with a charge-metastable one. This provides opportunities to further increase the fidelity. The relaxation mechanisms in the different regimes are investigated. This work demonstrates a readout that is fast, has one-electron signal and results in higher fidelity. It further predicts that going beyond 99:9% fidelity in a few microseconds of measurement time is within reach. Copyright © 2017, The Authors. All rights reserved.