Increased Reliability for Near-Term Quantum Computers via Low-Level Control

Although recent experimental progress in near-term quantum computers has generated signi?cant interest and optimism, a large gap remains from these quantum computers to practical applications with real-world value. This proposal outlines software development that will enable optimizations that cross between layers of the stack, unlocking ~20x e?ciency gains that were previously invisible. The emphasis on compilation across layers of the stack is contrary to the current design of quantum systems, which impose strict abstraction barriers that limit the scope of compiler optimizations. Software developed under this proposal will have two objectives. Objective A, decomposition to pulse-level controls, will enable quantum programs to be optimally expressed in terms of the native capabilities of the underlying quantum hardware. Objective B, low-level error mitigation, will enable the compiler to improve program success rates beyond what is traditionally possible. During the nine-month Phase I period, feasibility research was carried out pertaining to the same two objectives proposed for Phase II. Most of the research was performed in close collaboration with quantum hardware groups, both from the national research testbeds and from industry vendors. Funded outcomes included several papers (three released already and one currently under peer review) as well as the beta release of a quantum software platform. The quantum software platform has open-source frontends, ensuring ease of collaboration and deployment. Key software features enabled by Phase I funding include optimized native gate decomposition, equivalent circuit averaging, zero-noise extrapolation, and parametric two-qubit gates. Phase II comprises 11 tasks, beginning with Task 1: development of software tools for interfacing with a broader set of qubit platforms than was studied in Phase I. This will enable broader collaboration with national research testbeds, as well as industry leaders in quantum hardware. Among the remaining tasks, Tasks 2-7 pertain to decomposition to pulse-level controls (Objective A) and Tasks 8-11 pertain to low-level error mitigation (Objective B); all tasks are scoped for completion by April 2024. Successful execution of Phase II will enable software optimizations that make practical applications of quantum computing achievable 5 years sooner than otherwise possible. These practical applications will include tasks that are intractable for classical computers. For example, ongoing research with utility companies has suggested quantum speedups for solving power grid optimization tasks that are otherwise intractable. In the broader horizon, including Phase III, quantum applications will manifest in sectors important to national security, such as improving aircraft design. There are also anticipated public bene?ts through improved molecular simulation for tasks like higher-e?ciency fertilizer production, which currently consumes 3% of global energy production. The proposed technology will accelerate these commercial applications and bene?ts.