Boundaries of quantum supremacy via random circuit sampling

Journal Article · 11 April 2023 · npj Quantum Information

DOI: https://doi.org/10.1038/s41534-023-00703-x · OSTI ID:1969414

Zlokapa, Alexander  ^[1]; Villalonga, Benjamin ^[2]; Boixo, Sergio  ^[2]; Lidar, Daniel A.  ^[3]

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1. California Institute of Technology (CalTech), Pasadena, CA (United States)
2. Google AI Quantum, Venice, CA (United States)
3. Univ. of Southern California, Los Angeles, CA (United States)

Google’s quantum supremacy experiment heralded a transition point where quantum computers can evaluate a computational task, random circuit sampling, faster than classical supercomputers. We examine the constraints on the region of quantum advantage for quantum circuits with a larger number of qubits and gates than experimentally implemented. At near-term gate fidelities, we demonstrate that quantum supremacy is limited to circuits with a qubit count and circuit depth of a few hundred. Larger circuits encounter two distinct boundaries: a return of a classical advantage and practically infeasible quantum runtimes. Decreasing error rates cause the region of a quantum advantage to grow rapidly. At error rates required for early implementations of the surface code, the largest circuit size within the quantum supremacy regime coincides approximately with the smallest circuit size needed to implement error correction. Thus, the boundaries of quantum supremacy may fortuitously coincide with the advent of scalable, error-corrected quantum computing.

• Research Organization: California Institute of Technology (CalTech), Pasadena, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC); USDOE
• Grant/Contract Number: SC0019227
• OSTI ID: 1969414
• Alternate ID(s): OSTI ID: 2421052
• Journal Information: npj Quantum Information, Vol. 9, Issue 1; ISSN 2056-6387
• Publisher: Nature Partner JournalsCopyright Statement
• Country of Publication: United States
• Language: English