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arXiv · 2610.38780

An Eigenvector-Continued Green's Function Method

Stefano Brolli·Carlo Barbieri
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Abstract

Emulating the Green's function using reduced-order equations is challenging because of the amount of information it contains. This information includes the one-particle spectroscopy over the entire energy spectrum, the one-body density matrix, and the ground-state energy. Nevertheless, the computational speedup offered by emulators is essential for applications requiring repeated model evaluations, which are ubiquitous in many-body physics. These include parameter calibration, uncertainty quantification, phase-diagram mapping, and geometry optimization. In this Letter, we introduce a systematically improvable emulator based on eigenvector continuation and moment-matching. The resulting approximation, which we refer to as an ``eigenvector-continued Green's function,'' can be obtained by solving linear equations, enabling an efficient separation of the computational workload into offline and online stages.

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Stefano Brolli, Carlo Barbieri. 2026-10-28. An Eigenvector-Continued Green's Function Method. https://arxiv.org/abs/2610.38780

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