Related papers: Quantum algorithm for imaginary-time Green's functions

Quantum algorithm for imaginary-time Green's functions

URL: http://arxiv.org/abs/2309.09914v1
Date: Mon, 18 Sep 2023 16:28:11 GMT
Title: Quantum algorithm for imaginary-time Green's functions
Authors: Diksha Dhawan, Dominika Zgid and Mario Motta
Abstract summary: We present a hybrid quantum-classical algorithm to calculate the imaginary-time one-particle Green's function. The proposed algorithm combines variational quantum eigensolver and quantum subspace expansion to calculate Green's function.
Score: 0.0
License: http://creativecommons.org/licenses/by/4.0/
Abstract: Green's function methods lead to ab initio, systematically improvable simulations of molecules and materials while providing access to multiple experimentally observable properties such as the density of states and the spectral function. The calculation of the exact one-particle Green's function remains a significant challenge for classical computers and was attempted only on very small systems. Here, we present a hybrid quantum-classical algorithm to calculate the imaginary-time one-particle Green's function. The proposed algorithm combines variational quantum eigensolver and quantum subspace expansion to calculate Green's function in Lehmann's representation. We demonstrate the validity of this algorithm by simulating H$_2$ and H$_4$ on quantum simulators and on IBM's quantum devices.

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