Electromagnetic reactions from coupled-cluster theory

Sonia Bacca,Gaute Hagen,Mirko Miorelli

doi:10.1088/1742-6596/966/1/012019

Abstract

We review recent results for electromagnetic reactions and related sum rules in light and medium-mass nuclei obtained from coupled-cluster theory. In particular, we highlight our recent computations of the photodisintegration cross section of 40Ca and of the electric dipole polarizability for oxygen and calcium isotopes. We also provide new results for the Coulomb sum rule for 4He and 16O. For 4He we perform a thorough comparison of coupled-cluster theory with exact hyperspherical harmonics.

Highlights

Electromagnetic reactions have traditionally been a golden tool for studying nuclear dynamics
Because the computational cost of the coupled-cluster method scales mildly with respect to the mass number, this theory paves the way for many future investigations of electroweak reactions in mediummass nuclei, as it provides an ab initio approach where the continuum is properly taken into account
The electric dipole polarizability We focus our attention on the electric dipole polarizability

Summary

Introduction

Electromagnetic reactions have traditionally been a golden tool for studying nuclear dynamics. While a complete body of data has been collected over the years for stable nuclei, only recently have we begun to elucidate them in terms of first principle calculations This was achieved thanks to the introduction of a new ab initio computational tool, obtained from a coupled cluster theory formulation of the Lorentz integral transform method [3], which we will review below. The difficulty of studying Eq (1) lies in the fact that one needs, in principle, to calculate all the excited states |ψf , including all open channels in the continuum While this is possible for two- and three-body problems, starting at four nucleons it can only be done with restrictions in energy and/or with approximations. Because the computational cost of the coupled-cluster method scales mildly with respect to the mass number, this theory paves the way for many future investigations of electroweak reactions in mediummass nuclei, as it provides an ab initio approach where the continuum is properly taken into account

The photodisintegration cross section

Conclusions