BIMSRG: A novel many-body expansion formalism
28 October 2021
To kick off this section of the website, here is a short summary on a new article on Bogoliubov In-Medium Similarity Remnormalization Group that just got accepted in the European Physics Journal A. For now, you can read the preprint on arXiv.
In-Medium Similarity Renormalization Group has been a theory of choice for ab initio many-body practitioners, and with its Multi-Reference and Valence-Space counterparts have been instrumental in recent progress [1]. Though MR-IMSRG and VS-IMSRG are already able to tackle open-shell nuclei, they are pretty costly methods. Here we propose a single-reference, symmetry-breaking alternative, similar to the recently successful Bogoliubov MBPT [2].
Because BIMSRG inherently consists in a simple commutator, the structure of its contributions is pretty well constrained. This makes for an easy automated generation of diagrams and expressions from the get go. So with this new paper, we have updated the Automated Diagram Generator ADG to v3. It is now able to generate BIMSRG expressions at arbitrary orders and for traditional or exotic truncations, i.e. truncating all the operators at the same many-body level or not.
Edit on 10/01/22: The published article in now available on the EPJA website.
[1] H. Hergert, A Guided Tour of ab initio Nuclear Many-Body Theory, Front. in Phys. 8, 379 (2020)