05 07 11 0 v 3 2 6 O ct 2 00 6 Point-like topological defects in bilayer Quantum Hall systems

Following a suggestion given in [1], we show how a bilayer Quantum Hall system at fillings ν = m pm+2 can exhibit a point-like topological defect in its edge state structure. Indeed our CFT theory for such a system, the Twisted Model (TM), gives rise in a natural way to such a feature in the twisted sector. Our results are in agreement with recent experimental findings [2] which evidence the presence of a topological defect in the bilayer system.