5 research outputs found
Nonperturbative shell-model interactions from the in-medium similarity renormalization group
We present the first ab initio construction of valence-space Hamiltonians for
medium-mass nuclei based on chiral two- and three-nucleon interactions using
the in-medium similarity renormalization group. When applied to the oxygen
isotopes, we find experimental ground-state energies are well reproduced,
including the flat trend beyond the drip line at 24O. Similarly, natural-parity
spectra in 21,22,23,24O are in agreement with experiment, and we present
predictions for excited states in 25,26O. The results exhibit a weak dependence
on the harmonic-oscillator basis parameter and reproduce spectroscopy within
the standard sd valence space.Comment: 6 pages, 5 figures, published versio
In-Medium Similarity Renormalization Group with Chiral Two- Plus Three-Nucleon Interactions
We use the recently proposed In-Medium Similarity Renormalization Group
(IM-SRG) to carry out a systematic study of closed-shell nuclei up to
\nuc{Ni}{56}, based on chiral two- plus three-nucleon interactions. We
analyze the capabilities of the IM-SRG by comparing our results for the
ground-state energy to Coupled Cluster calculations, as well as to quasi-exact
results from the Importance-Truncated No-Core Shell Model. Using chiral two-
plus three-nucleon Hamiltonians whose resolution scales are lowered by
free-space SRG evolution, we obtain good agreement with experimental binding
energies in \nuc{He}{4} and the closed-shell oxygen isotopes, while the
calcium and nickel isotopes are somewhat overbound.Comment: 11 pages, 7 figures, submitted to Phys. Rev.
Living on the edge of stability, the limits of the nuclear landscape
A first-principles description of nuclear systems along the drip lines
presents a substantial theoretical and computational challenge. In this paper,
we discuss the nuclear theory roadmap, some of the key theoretical approaches,
and present selected results with a focus on long isotopic chains. An important
conclusion, which consistently emerges from these theoretical analyses, is that
three-nucleon forces are crucial for both global nuclear properties and
detailed nuclear structure, and that many-body correlations due to the coupling
to the particle continuum are essential as one approaches particle drip lines.
In the quest for a comprehensive nuclear theory, high performance computing
plays a key role.Comment: Contribution to proceedings of Nobel Symposium 152: Physics with
radioactive beams, June 2012, Gothenburg, Swede