In this talk we will summarise a systematic approach to constructing physical, i.e., gauge-invariant, fields describing charged particles. We will show that this can be done in a well defined way in abelian theories and perturbatively in non-abelian theories. Various perturbative tests in three and four dimensions will be reported. The existence of a non-perturbative obstruction to the observability of quarks will be demonstrated. Finally the extension to magnetic charges is discussed and their non-existence in pure SU(2) is shown. © 2004 Elsevier B.V. All rights reserved.
|Journal||Nuclear Physics B - Proceedings Supplements|
|Issue number||1-3 SUPPL.|
|Publication status||Published - 1 Jul 2004|