Darmstadt 2016 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 45: Postersession

HK 45.58: Poster

Mittwoch, 16. März 2016, 18:30–20:30, S1/05 22-24

Multiconfigurational Many-Body Perturbation Theory for Ab Initio Nuclear Structure — •Alexander Tichai and Robert Roth — Institut für Kernphysik, TU Darmstadt

Many-body perturbation theory provides a simple yet effective tool for ab initio calculations of nuclear observables. In the case of closed-shell systems the Hartree-Fock wave function defines an adequate starting point for the calculation of perturbative corrections. We have shown that the perturbation series converges exponentially fast and third-order partial sums yield a good approximation to the ground-state energy over the whole mass range up to ¹³²Sn. However, when proceeding to open-shell systems the ground-state wave function is no longer dominated by a single determinant. Therefore, we choose a multiconfigurational reference state arising from a diagonalization in a small model space. A recursive treatment allows for the calculation of energy corrections up to order 30 for small systems. Furthermore, we present second-order energy corrections for ground-state energies of the oxygen chain. We use two- and three-body interactions constructed from chiral effective field theory which are evolved via a similarity renormalization group transformation. All results are compared to configuration interaction and recent multireference in-medium similarity renormalization group calculations.

Supported by GSI, DFG (SFB 1245), HIC for FAIR, and BMBF (05P15RDFN1)