Nuclear physicists create scalable quantum ci

The Science

Simulating matter in extreme conditions is critical to answering fundamental questions about nature. The Standard Model of particle physics provides a set of equations that can explain these mysteries. However, in situations involving dynamics or high densities, the Standard Model equations are too difficult to solve or simulate with the most powerful classical supercomputers. Quantum computing offers the potential to efficiently simulate these systems in the future. However, one challenge is how to efficiently prepare the initial state of these simulations on the qubits of a quantum computer. In this research, scientists for the first time created scalable quantum circuits for the starting state for a collision of the type that happens in a particle accelerator. The test involves the strong interactions of the Standard Model. The researchers first determined these circuits for small systems using classical computers. Next, they took advantage of the quantum circuits’ scalability to prepare a simulation for large systems on a quantum computer. They used the technique successfully to simulate fundamental aspects of nuclear physics on more than 100 qubits of IBM’s quantum computers.

The Impact

Scalable quantum algorithms provide a path forward for complex simulations. This approach can address the preparation of the vacuum before a particle collision, systems at very high densities, and beams of hadrons. Researchers expect that future quantum simulations using these scalable circuits will surpass the abilities of classical computing. These simulations will provide insights into the mechanisms that govern the dynamics of fundamental particles and our universe. They may help answer why there is more matter than antimatter, how supernovae produce heavy elements, and the properties of matter at ultra-high densities. These quantum circuits should also help simulate other complex systems, including exotic types of materials.

Summary

Nuclear physicists performed the largest digital quantum simulation to date using IBM’s quantum computers. Symmetries and hierarchies in length scales of physical systems aided in the discovery of scalable quantum circuits for preparing states with localized correlations on a quantum computer. The researchers demonstrated the utility of this algorithm by preparing the vacuum and hadrons of quantum electrodynamics in one spatial dimension.

The team performed simulations using classical computers for small systems to determine the scalable quantum circuit elements, and to demonstrate that the states are systematically improvable. The researchers scaled up the circuits to system sizes of more than 100 qubits and implemented the circuits on IBM’s quantum computers. The team used the results from the quantum computer to determine properties of the vacuum with percent-level accuracy. In addition, they used scalable circuits to prepare pulses of hadrons, which were time evolved to observe their propagation. These developments provide a promising way to eventually perform dynamical simulations of matter in extreme conditions that are beyond the capabilities of classical computing alone.



Funding

This research was supported in part by the Department of Energy (DOE) Office of Science, Office of Nuclear Physics, InQubator for Quantum Simulation (IQuS) through the Quantum Horizons: QIS Research and Innovation for Nuclear Science Initiative; the Quantum Science Center (QSC), a DOE and University of Washington National Quantum Information Science Research Center. This research used resources of the Oak Ridge Leadership Computing Facility, a DOE Office of Science User Facility. This work was enabled, in part, by the use of advanced computational, storage and networking infrastructure provided by the Hyak supercomputer system at the University of Washington. The researchers acknowledge the use of IBM Quantum services for this work.