High-fidelity quantum architecture based on fluxonium qubits
Abstract
Commercial superconducting quantum computing has made rapid progress, but is dominated by work concentrating on scaling up transmon-based system. Here, we aim to establish systems based on fluxonium and fluxonium-like qubits as competitive across all relevant performance metrics. To achieve the goal of demonstrating a small-scale fluxonium processor, we will focus on a multi-pronged approach that will increase fluxonium coherence, optimize fidelity of multi-fluxonium gates, maintain low crosstalk in multi-fluxonium devices, and improve the overall measurement fidelity and measurement speed in these systems. Scientific Objectives: The primary goal of this proposal is to demonstrate the viability of the fluxonium qubit for scalable quantum computing. Our efforts will explore several schemes of two-qubit fluxonium gates to understand performance as it relates to speed, fidelity, backaction, crosstalk and ease of scaling in order to select candidates for future scaled work. We will concurrently work to improve coherence of fluxonium-based devices, incorporating materials advances including the use of alternative metals such as tantalum. We will consider new protocols for initialization and readout, and the potential role of fluxonium-like qubits in a scalable processor. Basic approaches: Our basic approach will include theoretical simulation of new coupling schemes, experimental validation of those ideas on custom-fabricated superconducting devices, and careful analysis and benchmarking to understand advantages and limitations of possible coupler types. Methods to be employed: We will use well-established methods that include fabrication and characterization of superconducting circuits in both planar and machined cavities, as well as microwave control in rotating and lab frames, measurement, and feedback at dilution refrigerator temperatures. Methods on the theory side will include analytical studies of simplified model systems, full numerical diagonalization of realistic system Hamiltonians, solving Lindblad master equations, and sampling quantum trajectory solutions to the stochastic Schrodinger equation to explore new gate approaches. Team: Our team consists of a collaboration between two experimental groups (Andrew Houck, Princeton University, and David Schuster, Stanford University) and two theoretical groups (Jens Koch, Northwestern University, and Alexandre Blais, University of Sherbrooke). The PIs have a long history of fruitful collaboration on superconducting quantum devices, including demonstrations of the first zero-pi qubit and high coherence planar fluxonium devices. Significance to the Advancement of Knowledge: A quantum computer could solve problems that are intractable with any known algorithm on a classical computer. While most commercial superconducting quantum computers use transmon qubits, this project aims to demonstrate that alternative devices could boost progress on the path to useful quantum computing. This would have significant applications to the Army s mission, including applications in cryptography, as well in developing and understanding novel materials. The advances pursued in this proposal take a different approach than the industry standard and could provide substantially improved components for future quantum technologies. This abstract is suitable for public release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 19, 2023
- Source ID
- W911NF2310101
Entities
People
- Andrew A. Houck
Organizations
- Army Contracting Command
- National Security Agency
- Princeton University