BOUNDARY DEGREES OF FREEDOM IN THE FRACTIONAL QUANTUM HALL-EFFECT - EXCITATIONS ON A COMMON BOUNDARY OF 2 SAMPLES

Using the field-theoretic method we have derived the boundary action f or the fermion Chern-Simons theory of the quantum Hall effect on a pla nar region with a boundary. We have computed both the bulk and edge re sponses of currents to the external electric held. From these we obtai n the well-known anomaly relation and the boundary Hall current withou t introducing any ad hoc assumptions such as the chirality condition. In addition, the edge current on the common boundary of two samples is found to be proportional to the difference between Chern-Simons coupl ing strengths.