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|Title:||Many-Body Effects in the Thermodynamic Properties of Fermi Liquids and the Electron-Phonon System and in the Excitation Spectrum of Liquid Helium-4|
|Department / Program:||Physics|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Physics, Condensed Matter|
|Abstract:||In this thesis I study two separate topics in many-body physics. In the first part I consider many-body effects in the thermodynamic properties of Fermi liquids and of the electron-phonon system. Using normal liquid ('3)He as an example, I show that the T('3)lnT corrections due to spin fluctuations account for the finite temperature corrections to the leading term in the specific heat. I also calculate and compare the statistical and the dynamical quasiparticle spectra and show that differences between them partially account for the discrepancy between the present and previous results. Spin fluctuation parameters determine from fits to specific heat of UPt(,3) and UAl(,2) are examined and applicability of simple spin-fluctuation models to these systems is discussed. In addition I consider the T('3)lnT contributions to the specific heat of metals due to the electron-phonon coupling and show how they may be viewed as being analogous to those from spin fluctuations.
In the second part of the thesis I review the application of polarization potential theory to the description of the excitations of liquid ('4)He at low temperature and I use recent experimental results to determine the parameters in the theory. I calculate the dispersion curve in the absence of dynamic mode-mode coupling and discuss the results.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2015-05-13|