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Title:  Variational theory of quantum fluids 
Author(s):  Schmidt, Kevin Edward 
Doctoral Committee Chair(s):  Pandharipande, V.R. 
Department / Program:  Physics 
Discipline:  Physics 
Degree:  Ph.D. 
Genre:  Dissertation 
Subject(s):  variational theory
quantum fluids microscopic twobody potential Landau's assumption 
Abstract:  A theory is developed to allow the systematic calculation of the properties of quantum fluids given the microscopic twobody potential. Physical arguments are used to construct a correlation operator that approximately transforms the states of a noninteracting system into the corresponding states of the interactingsystem. The theory can be regarded as a microscopic realization of Landau's assumption of a onetoone correspondence between the noninteracting and interacting states. It is variational since the correlation operator is determined by minimizing E(p) the expectation value of the groundstate energy. We first give a survey of various other manybody theories including the simpler Jastrow variational method. Differential equations are derived to calculate the correlation operator and the related Jastrow correlation" function. A comparison of results in several Bose systems with various methods is given. The Fermi hypernetted chain integral equations are generalized to allow the calculation of E(p) in Fermi systems, using the correlation operator wave function. The method is applied to liquid 3He and the v2model of nuclear matter. In 3He the correlation operator gives results in much closer agreement with experiment than that with the Jastrow wave function. A new set of hypernetted chain equations are then derived to allow the calculation of the excited st;ate energies in Bose systems. The theory is then applied to the calculation of the single quasiparticle excitation spectrum of liquid 4He. The spectrum is found to be a stringent test on the form of the correlation operator, deficiencies in the correlation operator giving corresponding errors in the spectrum. Good results are obtained for the density dependence of the roton energy. A variational principle for the free energy is used to generalize the correlation operator technique to finite temperatures. Results are given for the finite temperature properties of the v8model of nuclear matter. 
Issue Date:  1979 
Genre:  Dissertation / Thesis 
Type:  Text 
Language:  English 
URI:  http://hdl.handle.net/2142/25545 
Rights Information:  1979 Kevin Edward Schmidt 
Date Available in IDEALS:  20110628 
Identifier in Online Catalog:  409254 
This item appears in the following Collection(s)

Dissertations and Theses  Physics
Dissertations in Physics 
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois