In this contribution, we present an introduction to the physical principles
underlying the quantum Hall effect. The field theoretic approach to the
integral and fractional effect is sketched, with some emphasis on the mechanism
of electromagnetic gauge anomaly cancellation by chiral degrees of freedom
living on the edge of the sample. Applications of this formalism to the design
and theoretical interpretation of interference experiments are outlined.Comment: 20 pages, 8 figures; small corrections, replaced with published
versio
