It presents a detailed derivation of the

Feynman diagram technique and discusses the method of functional integrals in quantum theory.

1: The

Feynman diagram for the propagation of the electron core (-[e.sub.*], m) from (x, t) to (x', t') with no external scattering.

The

Feynman diagram is the most popular method for representing the terms in perturbative expressions.

There does not seem to be much to make of the shape of the constellation's major stars except perhaps a 'Y' or maybe a sort of

Feynman diagram.

The theory gave consistent answers to physical problems that the old theory could not and introduced the pioneering "

Feynman diagram," an aid to calculation that soon after became widely used.

A review of QED in the scientific journal Nature put it succinctly: "We get 40 seconds of a

Feynman diagram scrawled on that blackboard as a gee-whiz illustration ...

M38 has a fairly distinct cross shape, though some observers liken the shape to the Greek character for Pi, or possibly more like a

Feynman diagram to my eye.

gives the vertex factor (-ie)[(p.sub.E] + [q.sub.E]) which corresponds to the usual vertex of

Feynman diagram with two electron straight lines (with energies [p.sub.E] and [q.sub.E]) and one photon wave line in the conventional QED.

Although inscrutable to the uninitiated, a typical

Feynman diagram looks simple.

This allows quantum field theories to be investigated beyond the weak coupling regime where they may be defined as an asymptotic series in the coupling constant generated by

Feynman diagrams. The aim of this thesis is to apply these new techniques in novel areas to help build theoretical understanding.

which is calculated using the

Feynman diagrams and rules for the corresponding interaction.

Feynman diagrams for the subprocesses [mu]q([bar.q]) [right arrow] [[mu].sup.*]q([bar.q]) are shown in Figure 2.