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Title:Green's function Monte Carlo calculations of few-nucleon systems
Author(s):Pudliner, Brian Scott
Doctoral Committee Chair(s):Pandharipande, V.R.
Department / Program:Physics, Nuclear
Discipline:Physics, Nuclear
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Physics, Nuclear
Abstract:Recently, a realistic nucleon-nucleon potential has been developed with the goal of accurately reproducing isospin symmetry breaking effects in the nuclear interaction. We briefly discuss the motivation for this potential, called Argonne $v\sb{18},$ as well as the Urbana models of three-nucleon interactions. Our approach for modeling the ground states of nuclear systems begins with the development of a variational wave function. We discuss the basis for our variational wave functions and the Monte Carlo techniques used to evaluate expectation values with these wave functions. To determine the exact ground state, Green's function Monte Carlo (GFMC) techniques are used. We review the method of GFMC in general and then discuss its application to the problem of nuclear ground states in some detail.
We study a range of nuclear ground states using GFMC. A baseline calculation is done for the $\sp3H$ and $\sp4He$ ground states to fit the parameters of the three-nucleon potential and to evaluate the $\sp3He$-$\sp3H$ mass splitting. A spectrum of six-body states, including the lowest energy $\rm J\sp{\pi}=0\sp+,\ 1\sp+,\ 2\sp+,$ and 3$\sp+$ states of $\sp6Li$ and 0$\sp+$ states of $\sp6He$ and $\sp6Be,$ is then investigated. Isospin symmetry breaking effects are probed by measuring the $\sp6Be$-$\sp6He$ isovector and ${1\over2}(\sp6Be+{\sp6He})$-$\sp6Li$ isotensor mass splittings. The calculations are then extended to the $\sp7Li$ $\rm J\sp{\pi}={1\over2}\sp-,{3\over2}\sp-,{5\over2}\sp-,{7\over2}\sp-$ states and the isovector mass splitting $\sp7Be$-$\sp7Li$ is evaluated. To provide constraints on Skyrme-type effective interactions in neutron-rich systems, GFMC calculations for $\rm\sp8n(J\sp{\pi}=0\sp+)$ and $\rm\sp7n(J\sp{\pi}=1/2\sp-$ and $3/2\sp-)$ neutron drop clusters are carried out. The spin-orbit splitting of the $\sp7$n drops and the central density of $\sp8$n are used to offer improvements to energy-density functionals.
Issue Date:1996
Type:Text
Language:English
URI:http://hdl.handle.net/2142/23545
ISBN:9780591088281
Rights Information:Copyright 1996 Pudliner, Brian Scott
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9702643
OCLC Identifier:(UMI)AAI9702643


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