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Chang, Yia-Chung Perakis, Ilias 2011-05-04T18:13:09Z 2011-05-04T18:13:09Z 10000-01-01 1992 A new approach to the problem of X-ray edge singularities and peaks of many-body origin observed in the optical spectra is presented. We first establish the analogy between a system of one hole interacting with many electrons and the polaron, where one electron interacts with many phonons. We approach both cases as an eigenvalue problem for the time independent Schrodinger equation, obtain expressions for the many-body eigenstate& in a convenient basis and use them to understand the behavior of the system. In the case of a localized hole with infinite mass, we diagonalize the Hamiltonian exactly using first a wavefunction and then a noncanonical transformation. technique. We -use the expressions for the eigenstates to obtain the exact analytic formulas for the optical spectra, accurate over the whole frequency range. We then apply our techniques to the case of a finite mass valence hole, which is realized in modulation doped quantum wells or wires. In this case we approximately diagonalize the Hamiltonian by treating exactly the most important terms leading to nonperturbative behavior. The terms neglected are identified and can be treated in perturbation theory. Our method provides a clear physical picture and valuable insight into the accurate treatment of many-body Hamiltonians. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-04T18:13:09Z No. of bitstreams: 1 1992_perakis.pdf: 3599354 bytes, checksum: 07f67422f8aabcf7b8dcd15b23e69be7 (MD5) Made available in DSpace on 2011-05-04T18:13:09Z (GMT). No. of bitstreams: 1 1992_perakis.pdf: 3599354 bytes, checksum: 07f67422f8aabcf7b8dcd15b23e69be7 (MD5) Previous issue date: 1992 Restriction data tranferred 2014-07-01T11:12:11-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-04T18:13:09Z Item is restricted indefinitely. Thesis U of I Only 3576541 http://hdl.handle.net/2142/18905 en 1992 Ilias Perakis many-body metals quantum wells doped semiconductors semiconductors x-ray edge singularities Many-body effects in metals, modulation doped quantum wells and doped semiconductors Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.