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Structure of the QCD vacuum and low-lying eigenmodes of the Wilson-Dirac operator

This thesis details a study of the vacuum structure of QCD using the tool of lattice gauge theory. Chapter 1 gives an introduction to path integrals, semi-classical approximations to path integrals, instantons, topological charge and instanton phenomenology. Chapter 2 introduces lattice gauge theory and the problems of studying topological charge on the lattice. The cooling method and its pitfalls are discussed and details are given of a study undertaken of under-relaxed cooling. In Chapter 3 the algorithms that were developed to study the instantons on the cooled configurations are discussed. Chapter 4 gives the results for the structure of the vacuum: size distributions, spatial distributions, correlations between charges, and scaling of distributions with the lattice spacing. Chapter 5 discusses an exploratory study of the low-lying eigenmodes of the Wilson-Dirac operator. The zero-modes of both the unimproved and improved operators on cold and heated instantons are calculated and the lattice artefacts investigated. Chapter 6 contains my conclusions and suggestions for future work.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662153
Date January 1997
CreatorsSmith, Douglas Andrew
PublisherUniversity of Edinburgh
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://hdl.handle.net/1842/11413

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