Model quantum field theories

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5146513

Hill, B R

Some model quantum field theories of interest in elementary particle physics are studied. The first is a theory of a photon interacting with scalar, spinor and/or vector fields with arbitrary gauge-invariant interactions, in 2 + 1 dimensions. It is shown that to all orders in perturbation theory, all corrections to the topological mass term (beyond the known one-loop correction) vanish identically. The second model is explored for the possibility that non-topological solitons called Q-balls can exist in the chiral Lagrangian used to describe the eight light mesons. It was discovered that they could exist for reasonable sizes of the higher order terms in the chiral Lagrangian. The are approximately stable because they carry strangeness, hence the name K-balls. The last model is a theory of fermions on the lattice in which exciting numerical results were obtained by Weingarten and Velikson. They seemed to be demonstrating a chirally invariant way of defining a single fermion species on the lattice. A major element of their approach was destroying the regularity of the lattice with a random external field. The external field also destroys hermiticity. It is shown that their numerical results cannot be understood by doing perturbation theory in the size of the fluctuations in the external field. The results are also re-examined in a framework which goes beyond perturbation theory by finding self-consistent equations for the fermion propagator. In this framework, the conclusions of the perturbation theory are confirmed.

• Research Organization: Harvard Univ., Boston, MA (USA)
• OSTI ID: 5146513
• Country of Publication: United States
• Language: English

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