Quantum Computational Science

Mission statement

The mission of Oak Ridge National Laboratory’s (ORNL’s) Quantum Computational Science Group is to develop ways of using quantum computers to solve complex scientific problems that are beyond the reach of traditional computers. The group develops innovative quantum algorithms, devises efficient and robust implementations, formulates and runs benchmarks, and creates software for quantum-enhanced computational workflows.

Summary

Members of the Quantum Computational Science Group perform cutting-edge research spanning many facets of quantum computing, including fundamental theory, applications and algorithms, programming tools and compilers, hardware characterization, error mitigation and fault tolerance, modeling and simulation, and resource analysis. The group’s unifying goal is to make quantum computing more practical and applicable, both with today’s limited quantum processors and with future large-scale quantum computing systems. Group members primarily target problems in materials science, chemistry, combinatorial optimization, and ML. Potential applications for the group’s work include the development of advanced materials and chemical processes; optimization of energy production and distribution; and faster, more efficient AI.

In recent years, much of the group’s work has focused on developing algorithms and methods for today’s small, noisy quantum processors, such as those available through the ORNL Quantum Computing User Program. Although such devices are not capable of tackling real-world problems, developing proof-of-principle computations for these devices advances the understanding of quantum computing and demonstrates its potential for many different applications. Members of the group have developed innovative and efficient algorithms for simulating quantum materials; calculating accurate ground-state energies of molecules; performing combinatorial optimization; and performing ML tasks such as classification, kernel evaluation, and generative modeling. The group has also developed new methods for characterizing correlated errors and for quantifying the power of quantum processors to generate many-qubit entanglement.

Additionally, the Quantum Computational Science Group develops software frameworks and tools for incorporating quantum computing into conventional computational workflows. Building on ORNL’s XACC programming framework, members of the group are developing intermediate representations and execution engines to enable single-source hybrid quantum-classical computing with a variety of quantum processors and simulators. The group leads the development of a software infrastructure to manage quantum computing resources jointly with classical compute nodes in a user facility context. Group members also contribute to the development of efficient quantum circuit simulators using tensor networks and other advanced representations.

Looking to the future, the group has begun efforts to estimate and reduce the quantum resources needed to reach utility in various application areas. One line of work examining trade-offs between different fault-tolerant logical architectures has revealed opportunities to reduce resources by 10-100× in some cases.

Quantum computing is at an exciting point in its development. Over the next 5-8 years, the technology may transition from a proof of principle to a practical tool that brings unprecedented capabilities to world-class computing facilities, such as those at ORNL. Many challenges in algorithms and software will need to be overcome to reach this promising future, and the Quantum Computational Science Group is playing a key role in this effort.