Date of Award

1992

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Richard W. Haymaker

Abstract

The mechanism by which quarks, believed to be the fundamental constituents of matter, are prevented from existing in the free state is still unknown. The phenomenon of quark confinement is one of the fundamental problems in physics. One of the most viable candidates for a hypothesis of confinement is the dual superconductor mechanism that likens quark confinement to the Meissner effect in superconductors. The peculiarities of quark interactions make a numerical approach to the subject a necessity, and therefore, much of the work in this area has been done through the methods of lattice gauge theory, with the simplicities afforded by putting spacetime on a four-dimensional grid. Over the years a large amount of indirect evidence has accumulated that the dual superconductor hypothesis does indeed lead to quark confinement but unambiguous evidence has eluded research efforts until recently. This work presents the first direct proof of a Meissner-like effect that leads to confinement, using the numerical techniques of lattice gauge theory. It is shown that for a U(1) lattice gauge theory, that serves as a toy model for the real world of quarks, a dual London relation and an electric fluxoid quantization condition is satisfied, allowing us to conclude that the vacuum in this case acts like an extreme type-II superconductor, and that quarks are confined. We also show that SU(2) lattice gauge theory, which is qualitatively different and another step closer to reality, shows a Meissner-like effect. In contrast to the U(1) case, our results are found consistent with a dual version of the Ginsburg-Landau theory of superconductivity. We find reason to believe that the SU(2) vacuum behaves like a superconductor on the borderline between type-I and type-II. Our approach paves the way for a study of the more complicated theory, quantum chromodynamics, that is believed to describe quarks.

Pages

98

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