  Charged excitations in the fractional quantum Hall effect are known to carry
fractional charges, as theoretically predicted and experimentally verified.
Here we report on the dependence of the tunneling quasiparticle charge, as
determined via highly sensitive shot noise measurements, on the measurement
conditions, in the odd denominators states v=1/3 and v=7/3 and in the even
denominator state v=5/2. In particular, for very weak backscattering
probability and sufficiently small excitation energies (temperature and applied
voltage), tunneling charges across a constriction were found to be
significantly higher than the theoretically predicted fundamental quasiparticle
charges.
