OPTION 1: Qubits in Gate-Defined Silicon Quantum Dots
Abstract
Electrically-driven, gate-defined quantum dot qubits in silicon have progressed greatly in the last several years, with demonstrations of single-qubit and, very recently, two-qubit gates. Building on these advances, we propose to fabricate and characterize four-qubit devices with high-fidelity one- and two-qubit gates. We have assembled a tightly integrated team in which all members will make progress more rapidly than could be accomplished separately. There are a number of challenges in materials, device fabrication, and measurements that will need to be overcome, and our team has the expertise and demonstrated track record to meet those challenges. The materials essential for this work will be obtained from two primary sources. First, Wisconsin will fabricate heterostructures that will be used for materials exploration, device fabrication, and measurements. Second, and as recommended in response to the white paper , we have coordinated with the Matisse program and expect to receive approximately 10 wafers per year from them for this project; we anticipate that these heterostructures will also be available to all qubit characterization and fabrication teams proposed here. The Wisconsin and Matisse growth teams both have proven track records of providing heterostructures for successful qubit fabrication. Nanofabrication of devices is equally important, and we have planned careful comparison of device fabrication techniques between the three universities performing fabrication and Sandia National Laboratory; the nanofabrication part of the project is designed to try new processes rapidly (at the universities), share devices with all team members, and solidify and improve yield and throughput with the capabilities of Sandia. Qubit manipulation requires sophisticated dilution refrigerator measurements, and recent qubit accomplishments have been enabled by advances in this area at Delft, Harvard, and Wisconsin - sharing those techniques is a key advantage we envision as we move forward. New challenges will arise in devices with four coupled qubits, including cross-talk as well as overall increased complexity, and we will address these challenges both through extensions of our recently developed techniques for measuring single-spin, singlet-triplet, and quantum dot hybrid qubits, and through careful device design and novel control and measurement techniques. Solving the challenges that arise through growth, fabrication , and measurement of qubits will be an iterative process in which theory will play a critical role. Our team includes both analytical theory (Wisconsin) and numerical simulation (Purdue and Wisconsin) that has a demonstrated track record of enhancing the progress and understanding of qubit measurements. The combination of growth, nanofabrication, qubit measurement, and theory for both predictive guidance and feedback, is designed to enable a tightly integrated team approach to meet our primary scientific objectives: the development of high-fidelity one and two-qubit operations in silicon systems with four coupled quantum dot qubits.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1710274
Entities
People
- Mark Eriksson
Organizations
- Army Contracting Command
- National Security Agency
- University of Wisconsin–Madison