RT Journal Article
SR Electronic
T1 Witnessing eigenstates for quantum simulation of Hamiltonian spectra
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP eaap9646
DO 10.1126/sciadv.aap9646
VO 4
IS 1
A1 Santagati, Raffaele
A1 Wang, Jianwei
A1 Gentile, Antonio A.
A1 Paesani, Stefano
A1 Wiebe, Nathan
A1 McClean, Jarrod R.
A1 Morley-Short, Sam
A1 Shadbolt, Peter J.
A1 Bonneau, Damien
A1 Silverstone, Joshua W.
A1 Tew, David P.
A1 Zhou, Xiaoqi
A1 O’Brien, Jeremy L.
A1 Thompson, Mark G.
YR 2018
UL http://advances.sciencemag.org/content/4/1/eaap9646.abstract
AB 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.