Measuring, Modeling, and Mitigating Noise in Spin Qubits (M^3NSQ)
Abstract
We will carry out a comprehensive investigation of charge noise in quantum-dot spin qubits along two parallel tracks: multi-dot arrays, and quantum dots with integrated resonators. This effort is directly responsive to topic NS5, but also has significant overlap with topics FastCARS and ModQ. In each track, we will pursue a collaborative experimental and theoretical study of three thrusts: measuring, modeling, and mitigating noise. The measurement thrust focuses on acquiring a holistic characterization of the noise sources through measurements of charge noise on qubits as a function of multiple parameters (e.g., voltage, temperature, time, spatial location) and via different types of sensors. These measurements will be taken by the Nichol group at the University of Rochester. As part of this thrust, the Kestner group at University of Maryland, Baltimore County (UMBC) and the team of Gyure and Anderson at the University of California, Los Angeles (UCLA) will collaborate on the development of new sensing methods that use the field-dependent valley-orbital degree of freedom in silicon-based devices to efficiently acquire classical measurements of the electrical environment within the qubit dots without collapsing the quantum spin state. This will occur through dispersive microwave reflectometry of valley excitations in the presence of interface roughness. The implications for modular resonator-based architectures will be investigated by the Barnes and Economou group at the Virginia Polytechnic Institute and State University (VT) in collaboration with UMBC. The modeling thrust focuses on using the extensive set of measurement data to characterize the sources of charge noise. Experiments will be in close collaboration with a strong 3D device modeling effort by the UCLA team and temporal modeling by Norris and the Johns Hopkins University Applied Physics Laboratory (JHU/APL) team to produce insight into the physical sources of the material noise and its non-Gaussian characteristics. Through factorial hidden Markov, autoregressive moving average, and effective-mass Schr¬odinger-Poisson models coupled to full configuration interaction calculations, we aim to extract a more detailed understanding of the basic mechanisms than what exists today. Device modeling will also be used to improve the measurement techniques and sensor parameters, enhancing measurement capabilities, which will in turn inform more precise models. The mitigation thrust will combine the results of the measurement and modeling thrusts with predictive signal analysis theory from the JHU/APL team to enable real-time closed-loop mitigation of the qubitÕs local noise environments and improved quantum operations, including both local and entangling gates on singlet-triplet qubits. This effort will culminate with experimental demonstration of noise mitigation of a two-qubit gate in the multi-dot array and of a single-qubit in the resonator-based device. The VT group will study how the local noise sources propagate nonlocally when integrating small multi-dot arrays into a modular resonator-coupled architecture. Both tracks and all three of these thrusts have crosslinks between the five institutions and share a common focus on experiments specifically designed for studying noise in a linear array of silicon quantum dots.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 19, 2023
- Source ID
- W911NF2310115
Entities
People
- Jason Kestner
Organizations
- Army Contracting Command
- National Security Agency
- University of Maryland, Baltimore County