An occupation number quantum subspace expansion approach to compute the
single-particle Green function
- URL: http://arxiv.org/abs/2312.13497v1
- Date: Thu, 21 Dec 2023 00:21:17 GMT
- Title: An occupation number quantum subspace expansion approach to compute the
single-particle Green function
- Authors: B. Gauthier, P. Rosenberg, A. Foley, M. Charlebois
- Abstract summary: We introduce a hybrid quantum-classical algorithm to compute the Green function for strongly correlated electrons on noisy quantum devices.
For a 2 site system we find good agreement between the results of quantum simulations and the exact result for the local spectral function.
A simulation of a 4 site system carried out on classical hardware suggests that the approach can achieve similar accuracy for larger systems.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We introduce a hybrid quantum-classical algorithm to compute the Green
function for strongly correlated electrons on noisy intermediate-scale quantum
(NISQ) devices. The technique consists in the construction of a non-orthogonal
excitation basis composed of a set of single-particle excitations generated by
occupation number operators. The excited sectors of the Hamiltonian in this
basis can then be measured on the quantum device and a classical
post-processing procedure yields the Green function in the Lehmann
representation. The technique allow for noise filtering, a useful feature for
NISQ devices. To validate the approach, we carry out a set of
proof-of-principle calculations on the single-band Hubbard model on IBM quantum
hardware. For a 2 site system we find good agreement between the results of
quantum simulations and the exact result for the local spectral function. A
simulation of a 4 site system carried out on classical hardware suggests that
the approach can achieve similar accuracy for larger systems.
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