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 ${\mathit{e}}^{\mathrm{*}}$=νe(ν<1). Given the appropriate geometry, can one observe multiple Aharonov-Bohm (MAB) oscillations of basic periodicity h/${\mathit{e}}^{\mathrm{*}}$? We show that such oscillations may indeed be observed over a time scale that can be made macroscopically long. This is the result of a dynamical symmetry breaking of the ground state. When fractional charges become abundant, only standard AB oscillations (of period h/e) will be observed, and the measured FQHE conductivity will be quenched either to zero or to a nontrivial integer. These effects may be manifested in dc measurements as well, the physics being related to that discussed in the context of the Coulomb blockade.