DETECTION OF FRACTIONAL CHARGE AND QUENCHING OF THE QUANTUM HALL-EFFECT

A two-dimensional electron gas in the fractional-quantum-Hall-effect ( FQHE) regime is characterized by fractionally charged excitations e = ve (v < 1). Given the appropriate geometry, can one observe multiple Aharonov-Bohm (MAB) oscillations of basic periodicity h/e? We show th at such oscillations may indeed be observed over a time scale that can be made macroscopically long. This is the result of a dynamical symme try breaking of the ground state. When fractional charges become abund ant, only standard AB oscillations (of period h/e) will be observed, a nd the measured FQHE conductivity will be quenched either to zero or t o a nontrivial integer. These effects may be manifested in dc measurem ents as well, the physics being related to that discussed in the conte xt of the Coulomb blockade.