Darmstadt 2016 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 45: Postersession

HK 45.36: Poster

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

Correlated random-phase approximation from densities and in-medium matrix elements — •Richard Trippel and Robert Roth — Institut für Kernphysik, Technische Universität Darmstadt

The random-phase approximation (RPA) as well as the second RPA (SRPA) are established tools for the study of collective excitations in nuclei. Addressing the well known lack of correlations, we derived a universal framework for a fully correlated RPA based on the use of one- and two-body densities. We apply densities from coupled cluster theory and investigate the impact of correlations. As an alternative approach to correlations we use matrix elements transformed via in-medium similarity renormalization group (IM-SRG) in combination with RPA and SRPA. We find that within SRPA the use of IM-SRG matrix elements leads to the disappearance of instabilities of low-lying states. For the calculations we use normal-ordered two- plus three-body interactions derived from chiral effective field theory. We apply different Hamiltonians to a number of doubly-magic nuclei and calculate electric transition strengths. Supported by DFG (SFB 1245), HIC for FAIR and BMBF (06DA7047I)