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Statut |
Confirmé |
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Série |
NUC-THEO |
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Domaines |
nucl-th |
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Date |
Mercredi 13 Décembre 2017 |
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Heure |
11:30 |
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Institut |
IPN |
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Salle |
Bâtiment 100, Salle A015 |
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Nom de l'orateur |
Tichai |
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Prenom de l'orateur |
Alexander |
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Addresse email de l'orateur |
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Institution de l'orateur |
CEA Saclay ESNT/DPHN |
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Titre |
Many-Body Perturbation Theory for Ab Initio Nuclear Structure |
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Résumé |
The reach of ab initio calculations has extended significantly over the past years. In
particular systems revealing a closed-shell character can be described efficiently up to
the tin isotopic chain via controlled many-body expansions like coupled-cluster the-
ory, the in-medium similarity renormalization group or self-consistent Green func-
tion techniques. However, the transfer of such methods to open-shell nuclei requires
a highly non-trivial extension. In this talk we will discuss many-body perturbation
theory (MBPT) as a light-weighted alternative and give a pedestrian introduction to
MBPT based on a Hartree-Fock reference state. Low-order energy corrections for
ground states of closed-shell nuclei will be discussed using state-of-the-art chiral
interactions.
The conceptual simplicity of MBPT allows for a direct generalization to open-shell
systems by using correlated reference states. First I will present a MBPT version us-
ing a multi-configurational reference state arising from a prior no-core shell-model
calculation (NCSM). We present recent calculations of second-order energy correc-
tions of spectra of even and odd carbon and oxygen isotopes and compare them to
exact diagonalizations from large-scale NCSM calculations. Additionally, we will
provide first results on the dripline physics of the fluorine isotopic chain.
In a complementary ansatz we use symmetry-broken reference states from a Hartree-
Fock-Bogoliubov (HFB) calculation as starting point for the correlation expansion
and reformulate MBPT in a quasiparticle setting yielding the so-called Bogoliubov
MBPT (BMBPT). We present preliminary results for the oxygen chain and compare
them to other state-of-the-art many-body approaches and provide an outlook on
future applications of symmetry-broken many-body approaches. |
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Numéro de preprint arXiv |
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Commentaires |
$ $ |
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Fichiers attachés |
- 2017_12_20_A_Tichai.pdf (214032 bytes)
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