Self-Consistent Green's Function Theory for Atomic Nuclei

Abstract

Nuclear structure theory has recently gone through a major renewal with the development of ab initio techniques that can be applied to a large number of atomic nuclei, well-beyond the light sector that had been traditionally targeted in the past. Self-consistent Green's function theory is one among these techniques. The present work aims to give an overview of the self-consistent Green's function approach for atomic nuclei, including examples of recent applications and a discussion on the perspectives for extending the method to nuclear reactions, doubly open-shell systems, and heavy nuclei.

Beta Decay in Medium-Mass Nuclei with the In-Medium Similarity Renormalization Group

“…[26] for more details).) As a further generalization, we may define a valence space (e.g., the sd-shell above an 16 O core), and define H od as any part of H which connects a valence configuration to a non-valence configuration (specifically, we partition all single-particle states into core, valence, and excluded orbits. A "valence configuration" is one with all core orbits occupied and all excluded orbits unoccupied).…”

“…Nevertheless, progress has been made over the past few decades so that the internucleon interaction can be systematically constructed within an effective field theory framework [8][9][10]. Simultaneously, advances in many-body theory and computational resources have enabled ab initio treatment of the medium-mass nuclei which are often relevant for BSM searches [11][12][13][14][15][16][17]. Of course, more work remains to be done, both on the effective field theory side [18][19][20] and on understanding how approximation schemes in ab initio calculations impact the observables in question.…”

ADG: automated generation and evaluation of many-body diagrams

“…Indeed, truncating the expansion provides a solution whose numerical cost scales polynomially with A. The most prominent examples of such methods are many-body perturbation theory (MBPT) [7][8][9][10][11][12], self-consistent Green's function (SCGF) theory [13][14][15][16][17], coupled-cluster (CC) theory [18][19][20][21] and the in-medium similarity renormalization group (IMSRG) approach [22][23][24][25][26][27][28].…”

“…https://pypi.org/project/adg/ 16. https://github.com/adgproject/adg 17. Depending on the system, it might be necessary either to use the "--user" flag to install it only for a specific user or to run the previous command with "sudo -H" to install it system-wide.…”

Investigation of the ground-state spin inversion in the neutron-rich Cl47,49 isotopes

“…Data are compared to state-of-the-art theoretical calculations, including shell-model and ab initio methods. These latter methods are now able to compute open-shell, intermediate-mass, odd-even nuclei in their full-space implementation [29,30], and all nuclei accessible to standard shell-model approaches via valence-space techniques [31]. Neutron-rich nuclei constitute an important benchmark for the development of both many-body methods and input nuclear Hamiltonians, currently modeled within the framework of chiral effective field theory (EFT) [32,33].…”