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application/pdf 1973_root.pdf (5MB)  1973 Root 
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Title:  Quantum field theories on the light front 
Author(s):  Root, Robert Gerald 
Director of Research:  Chang, ShauJin 
Department / Program:  Physics 
Discipline:  Physics 
Degree:  Ph.D. 
Genre:  Dissertation 
Subject(s):  light fronts
quantum mechanics quantum field theories 
Abstract:  Several popular field theories are quantized on light fronts, that is O 3 surfaces defined by x + = x0 + x3 = constant. Schwinger's quantum ac tion principle is employed to deduce the correct canonical equalx+(anti) commutation relations. The formulations developed for free fields of spino,t,l, and 2 are equivalent to the equaltime formulations. However, in the new formulations it is easy to take the limit of vanishing mass in the massive spin2 theory. Consistent formulations are found for selfinteracting scalar fields and for scalar and Dirac fields interacting through simple couplings. The Smatrix elements are given by a x+ordered product rather than the usual timeordered product. The Feynman rules for these Smatrix elements are identical to the old rules in the case of the selfinteracting scalar theory, but they differ by noncovariant terms for the interacting Dirac theory. A formal proof of the equivalence of the Sm3trix in the new formulation and the usual timeordered expansion is given for renormalized interacting Dirac fields. A set of generalized Schwinger conditions for a quantum theory to be Lorentz invariant are verified in scalar and Dirac field theories; then the presence of cnumber Schwinger terms in the equalx+ stress tensor commutators is demonstrated. This new formulation is used to find spectral sum rules and leading singularities of both the Green's function and the product of field operators near the light front. The implications for current algebra sum rules are mentioned. Reduction formulas for scalar and Dirac particles are derived. 
Issue Date:  1973 
Genre:  Dissertation / Thesis 
Type:  Text 
Language:  English 
URI:  http://hdl.handle.net/2142/30685 
Rights Information:  © 1973 Robert Gerald Root 
Date Available in IDEALS:  20120419 
Identifier in Online Catalog:  2367971 
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