Witnessing eigenstates for quantum simulation of Hamiltonian spectra

Raffaele Santagati, Jianwei Wang, Antonio A. Gentile, Stefano Paesani, Nathan Wiebe, Jarrod R. McClean, Sam Morley-Short, Peter J. Shadbolt, Damien Bonneau, Joshua W. Silverstone, David P. Tew, X. Zhou, Jeremy L. O’Brien, Mark G. Thompson

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The efficient calculation of Hamiltonian spectra, a problem often intractable on classical machines, can find application in many fields, from physics to chemistry. We introduce the concept of an “eigenstate witness” and, through it, provide a new quantum approach that combines variational methods and phase estimation to approximate eigenvalues for both ground and excited States. This protocol is experimentally verified on a programmable silicon quantum photonic chip, a mass-manufacturable platform, which embeds entangled state generation, arbitrary controlled unitary operations, and projective measurements. Both ground and excited States are experimentally found with fidelities >99%, and their eigenvalues are estimated with 32 bits of precision. We also investigate and discuss the scalability of the approach and study its performance through numerical simulations of more complex Hamiltonians. This result shows promising progress toward quantum chemistry on quantum computers.

Original languageEnglish
Article number9646
JournalScience Advances
Volume4
Issue number1
DOIs
Publication statusPublished - Jan 2018
Externally publishedYes

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    Santagati, R., Wang, J., Gentile, A. A., Paesani, S., Wiebe, N., McClean, J. R., Morley-Short, S., Shadbolt, P. J., Bonneau, D., Silverstone, J. W., Tew, D. P., Zhou, X., O’Brien, J. L., & Thompson, M. G. (2018). Witnessing eigenstates for quantum simulation of Hamiltonian spectra. Science Advances, 4(1), [9646]. https://doi.org/10.1126/sciadv.aap9646