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text Stone, Michael Olson, David Paul 2012-01-20T21:28:06Z 2012-01-20T21:28:06Z 10000-01-01 1988 In the first part of this thesis, a stochastic adaptation of the microcanonical simulation method is applied to the numerical simulation of the Su-Schrieffer-Heeger Hamiltonian for polyacetylene, a one-dimensional polymer where fermion-boson interactions play a dominant role in the dynamics of the system. The pure microcanonical simulation method fails in the marginally ergodic case and a stochastic adaptation, the hybrid microcanonical method, is employed to resolve problems with ergodicity. The hybrid method is shown to be an efficient method for higher dimensional fermionic quantum systems. In the second part of this thesis, a numerical simulation of the evolution of a network of global cosmic strings in an expanding Robertson-Walker universe is carried out. The system is quenched through an order-disorder phase transition and the nature of the string distribution is examined. While the string distribution observed at the phase transition is in good agreement with earlier estimates, the simulation reveals that the dynamics of the strings are suppressed by interactions with the Goldstone field. The network decays by topological annihilation and no spatial correlations are observed at any point in the simulation. Submitted by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-20T21:28:06Z No. of bitstreams: 1 1988_olson.pdf: 2002098 bytes, checksum: be1b1589c00581813619b5003e0c36eb (MD5) Made available in DSpace on 2012-01-20T21:28:06Z (GMT). No. of bitstreams: 1 1988_olson.pdf: 2002098 bytes, checksum: be1b1589c00581813619b5003e0c36eb (MD5) Previous issue date: 1988 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Rauber (crauber2@illinois.edu) on 2012-01-20T21:28:06Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:10:33-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation dissertation U of I Only http://hdl.handle.net/2142/28671 en 1988 David Paul Olson quantum field theory microcanonical simulation Microcanonical simulations in classical and quantum field theory Dissertation / Thesis Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.