Ab initio Bogoliubov many-body perturbation theory: closed-form constraint on the average particle number

Fuente: arXiv
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Main Authors: Demol, Pepijn, Duguet, Thomas, Tichai, Alexander
Format: Preprint
Published: 2024
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_version_ 1866916631481942016
author Demol, Pepijn
Duguet, Thomas
Tichai, Alexander
author_facet Demol, Pepijn
Duguet, Thomas
Tichai, Alexander
contents Bogoliubov many-body perturbation theory (BMBPT) relying on the breaking of U(1) global gauge symmetry has been recently formulated and applied to extend the applicability of standard perturbation theory to ab initio calculations of atomic nuclei away from shell closures. So far, practical applications have been limited to second-order calculations due to the lack of a generic algorithm to constrain the average particle number of the symmetry-broken state. This limitation is presently lifted and a general BMBPT formalism is presented that allows to constrain the particle-number expectation value at arbitrary order P. The constraint can be incorporated in closed form by solving a polynomial equation of degree P-1. The numerical procedure is illustrated through BMBPT(3) calculations of calcium isotopes using a nuclear Hamiltonian derived within chiral effective field theory.
format Preprint
id arxiv_https___arxiv_org_abs_2407_16841
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ab initio Bogoliubov many-body perturbation theory: closed-form constraint on the average particle number
Demol, Pepijn
Duguet, Thomas
Tichai, Alexander
Nuclear Theory
Bogoliubov many-body perturbation theory (BMBPT) relying on the breaking of U(1) global gauge symmetry has been recently formulated and applied to extend the applicability of standard perturbation theory to ab initio calculations of atomic nuclei away from shell closures. So far, practical applications have been limited to second-order calculations due to the lack of a generic algorithm to constrain the average particle number of the symmetry-broken state. This limitation is presently lifted and a general BMBPT formalism is presented that allows to constrain the particle-number expectation value at arbitrary order P. The constraint can be incorporated in closed form by solving a polynomial equation of degree P-1. The numerical procedure is illustrated through BMBPT(3) calculations of calcium isotopes using a nuclear Hamiltonian derived within chiral effective field theory.
title Ab initio Bogoliubov many-body perturbation theory: closed-form constraint on the average particle number
topic Nuclear Theory
url https://arxiv.org/abs/2407.16841