A. Fabrocini

Spectral function of finite nuclei and scattering of GeV electrons

Abstract We employ the local-density approximation to derive the spectral function P( k , E) of finite nuclei. For various densities of nuclear matter we calculate P( k , E) , and split it into the single-particle and correlated parts. For finite nuclei P( k , E) is calculated by combining the nuclear-matter correlated part, evaluated in local-density approximation, with the finite-nucleus single-particle part obtained from mean-field calculations or (e, e′p) experiments. These spectral functions are used to calculate cross sections for inclusive electron-nucleus scattering at large momentum transfer. The recoil-nucleon final-state interaction is treated in the local-density approximation as well.

Effective mass of one 4He atom in liquid 3He.

A microscopic calculation of the effective mass of one [sup 4]He impurity in homogeneous liquid [sup 3]He at zero temperature is performed for an extended Jastrow-Slater wave function, including two- and three-body dynamical correlations and also backflow correlations between the [sup 4]He atom and the particles in the medium. The effective mass at equilibrium density, [ital m][l angle][ital main][r angle][sub 4][sup *]/[ital m][sub 4]=1.21, is in very good agreement with the recent experimental determination by Edwards [ital et] [ital al]. The three-particle correlations appear to give a small contribution to the effective mass and different approximations for the three-particle distribution function give almost identical results for [ital m][sub 4][sup *]/[ital m][sub 4].

Microscopic calculation of the longitudinal response of nuclear matter

Abstract The orthogonalized version of correlated basis theory is used to evaluate the longitudinal response of nuclear matter from realistic nuclear interaction. The correlated 1plh excited states have been fully retained in the calculation. The 2p2h correlated states entering the self-energy insertions, have also been treated exactly. The calculated response results to be in good agreement with previous similar calculations of the density response of symmetrical nuclear matter which included the effect of 2p2h correlated states approximately via the optical potential. Its comparison with the response calculated along the Brueckner theory in the y -scaling region is also discussed. At moderately high values of the momentum transfer, the longitudinal response is compared with the available experimental data from quasi-free electron scattering off medium-heavy nuclei. Our theoretical estimates are in fair agreement with the data on 40 Ca, 48 Ca, 56 Fe and 238 U, except at the highest values of both the momentum transfer and missing energy.

Effective mass of one He 4 atom in liquid He 3

A microscopic calculation of the effective mass of one [sup 4]He impurity in homogeneous liquid [sup 3]He at zero temperature is performed for an extended Jastrow-Slater wave function, including two- and three-body dynamical correlations and also backflow correlations between the [sup 4]He atom and the particles in the medium. The effective mass at equilibrium density, [ital m][l angle][ital main][r angle][sub 4][sup *]/[ital m][sub 4]=1.21, is in very good agreement with the recent experimental determination by Edwards [ital et] [ital al]. The three-particle correlations appear to give a small contribution to the effective mass and different approximations for the three-particle distribution function give almost identical results for [ital m][sub 4][sup *]/[ital m][sub 4].

Introduction to modern methods of quantum many-body theory and their applications

Density functional theory microscopic description of quantum liquids the coupled cluster method and its application experiments with a Rubidium Bose-Einstein condensate theoretical aspects of Bose-Einstein condensation elementary excitations and dynamic structure of quantum fluids theory of correlated basis functions the magnetic susceptibility of liquid 3He the hyperspherical harmonic method - a review and some recent developments the nuclear many-body problem.

Model calculations of doubly closed shell nuclei in CBF theory (I)

Abstract Correlated basis function theory and Fermi hypernetted chain theory are extended to treat finite Fermi systems. In this first paper, the effects of the scalar nucleon-nucleon correlations are investigated by studying some model N = Z nuclei. Results of calculations performed using central nucleon-nucleon potentials, without tensor components, are presented and are compared with results from other theories.

Beyond the Gross-Pitaevskii approximation: Local density versus correlated basis approach for trapped bosons

We study the ground state of a system of Bose hard spheres trapped in an isotropic harmonic potential to investigate the effect of the interatomic correlations and the accuracy of the Gross-Pitaevskii equation. We compare a local-density approximation, based on the energy functional derived from the low-density expansion of the energy of the uniform hard-sphere gas, and a correlated wave-function approach, which explicitly introduces the correlations induced by the potential. Both higher-order terms in the low-density expansion, beyond Gross-Pitaevskii, and explicit dynamical correlations have effects of the order of percent when the

Model calculations of doubly closed shell nuclei in CBF theory III. jj coupling and isospin dependence

Abstract Correlated basis function theory and Fermi hypernetted chain technique are extended to study medium-heavy, doubly closed shell nuclei in the jj coupling scheme, with different single-particle wave functions for protons and neutrons and isospin-dependent two-body correlations. Central semirealistic interactions are used. Ground-state energies, one-body densities, distribution functions and momentum distributions are calculated for 12 C, 16 O, 40 Ca, 48 Ca and 208 Pb nuclei. The values of the ground-state energies provided by isospin-dependent correlations are significantly lower than those obtained with isospin-independent correlations. In finite nuclear systems, the two-body Euler equations provide correlation functions variationally more effective than those obtained with the same technique in infinite nuclear matter.

Ground state of N5Z doubly closed shell nuclei in correlated basis function theory

~Received 6 October 1997! The ground state properties of N5Z doubly closed shell nuclei are studied within correlated basis function theory. A truncated version of the Urbana v 14 realistic potential, with spin, isospin, and tensor components, is adopted, together with state-dependent correlations. Fermi hypernetted chain integral equations are used to evaluate the density, distribution function, and ground state energy of 16 O and 40 Ca. The nuclear matter single operator chain approximation is extended to finite nuclear systems, to deal with the noncommuting part of the correlation operators. The results favorably compare with variational Monte Carlo estimates, when available, and provide a first substantial check of the accuracy of the cluster summation method for state-dependent correlations. We achieve in finite nuclei a treatment of noncentral interactions and correlations having, at least, the same level of accuracy as in nuclear matter. This opens the way for a microscopic study of the medium heavy nuclei ground state using present day realistic Hamiltonians. @S0556-2813~98!00104-6#

Spectral function of medium-heavy nuclei and electron scattering

Abstract We calculate the correlated part of the nuclear matter spectral function at various densities employing correlated basis function theory. The correlated part of the spectral function for finite nuclei is obtained from the nuclear matter results by using local density approximation, whereas the mean-field part is extracted from ( e , t ′ p ) scattering data. The resulting P ( k , E) is used to study inclusive electron scattering at large q; the final state interaction effects are also treated in local density approximation.