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arXiv · 2605.30527

Time-ordered Diagrammatic Monte Carlo for atomic nuclei

Stefano Brolli·Carlo Barbieri
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Abstract

Diagrammatic Monte Carlo provides a systematically improvable framework for stochastically resumming many-body expansions to high orders through direct sampling of diagram topologies. We advance our earlier work by introducing a novel time-ordered Diagrammatic Monte Carlo algorithm for the single-particle Green's function. The algorithm is tailored to finite nuclei, formulated in discrete model spaces and applicable to arbitrary two-body interactions. The new time-ordered diagrammatic Monte Carlo algorithm is based on the on-the-fly evaluation of time-ordered Goldstone diagrams, avoiding explicit diagram enumeration and expensive frequency integration. We show the algorithm by computing ${}^{16}$O up to fifth order in a reduced model space using optimized reference state orbitals and including effective three-body forces. Benchmarking against established truncation schemes in ab initio nuclear theory demonstrates its potential to overcome the limitations of current many-body approaches.

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Stefano Brolli, Carlo Barbieri. 2026-05-28. Time-ordered Diagrammatic Monte Carlo for atomic nuclei. https://arxiv.org/abs/2605.30527

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