In-medium k-body reduction of n-body operators: A flexible symmetry-conserving approach based on the sole one-body density matrix.

Autor: Frosini, M., Duguet, T., Bally, B., Beaujeault-Taudière, Y., Ebran, J.-P., Somà, V.
Předmět:
Zdroj: European Physical Journal A -- Hadrons & Nuclei; Apr2021, Vol. 57 Issue 4, p1-29, 29p
Abstrakt: The computational cost of ab initio nuclear structure calculations is rendered particularly acute by the presence of (at least) three-nucleon interactions. This feature becomes especially critical now that many-body methods aim at extending their reach beyond mid-mass nuclei. Consequently, state-of-the-art ab initio calculations are typically performed while approximating three-nucleon interactions in terms of effective, i.e. system-dependent, zero-, one- and two-nucleon operators. While straightforward in doubly closed-shell nuclei, existing approximation methods based on normal-ordering techniques involve either two- and three-body density matrices or a symmetry-breaking one-body density matrix in open-shell systems. In order to avoid such complications, a simple, flexible, universal and accurate approximation technique involving the convolution of the initial operator with a sole symmetry-invariant one-body matrix is presently formulated and tested numerically. Employed with a low-resolution Hamiltonian, the novel approximation method is shown to induce errors below 2 - 3 % across a large range of nuclei, observables and many-body methods. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
Externí odkaz:
Nepřihlášeným uživatelům se plný text nezobrazuje