The Unitary Correlation Operator Method (UCOM) provides a powerful scheme for carrying out ab initio nuclear structure calculations [1, 2, 3, 4]. In particular, it makes it possible to combine numerically affordable manybody Hilbert spaces with modern realistic NN interactions. Short-range correlations are explicitly taken into account. First results ranging from no-core shell model to HartreeF...

We have applied our proposed higher random-phase approximation (HRPA) to the T and V states of ethylene. In the HRPA, unlike the RPA, one solves for the excitation frequencies and the ground-state correlations self-consistently. We also develop a simplified scheme (SHRPA) for solving the equations of the HRPA, using only molecular integrals sufficient for the usual RPA calculations. The HRPA re...

The Gaussian expansion method (GEM) is applied to calculations of the nuclear excitations in the random-phase approximation (RPA). We adopt the massindependent basis-set that is successful in the mean-field calculations. The RPA results obtained by the GEM are compared with those obtained by several other available methods in Ca isotopes, by using a density-dependent contact interaction along w...

We have studied the precession mode, the rotational excitation built on the high-K isomeric state, in comparison with the recently identified wobbling mode. The randomphase-approximation (RPA) formalism, which has been developed for the nuclear wobbling motion, is invoked and the precession phonon is obtained by the non-collective axiallysymmetric limit of the formalism. The excitation energies...

We provide accurate assessments of the consequences of violations of self-consistency in HartreeFock (HF) based random phase approximation (RPA) calculations of the centroid energy Ecen of isoscalar and isovector giant resonances of multi-polarities L = 0 − 3 in a wide range of nuclei. This is done by carrying out highly accurate HF-RPA calculations neglecting the particle-hole (ph) spin-orbit ...

We discuss novel features of a new continuum RPA formulated in the coordinate-space Hartree-Fock-Bogoliubov framework. This continuum quasiparticle RPA takes into account both the oneand two-particle escaping channels. The theory is tested with numerical calculations for monopole, dipole and quadrupole excitations in neutron-rich oxygen isotopes near the drip-line. Effects of the particle-parti...

The partition function by means of the static path approximation (SPA) plus the random-phase approximation (RPA) treatment can be written as a contour integral form without solving the RPA equations for a separable interaction. This method is an efficient way to evaluate numerically the partition function for realistic calculations. As an illustration, we adopt the pairing model at finite tempe...

Using effective lagrangians which correspond to a wide range of values for K1 relativistic RPA calculations are performed for monopole and dipole compression modes in nuclei. It is found that Dirac sea states have an important effect on compression mode energies. Including these negative energy states into relativistic RPA brings the results into general agreement with those of time-dependent r...

We study the density instabilities of a two-dimensional gas of dipolar fermions with aligned dipole moments. The random phase approximation (RPA) for the density-density response function is never accurate for the dipolar gas, and so we incorporate correlations beyond RPA via an improved version of the Singwi-Tosi-Land-Sjölander scheme. In addition to density-wave instabilities, our formalism c...