Elementary excitations in the fractional quantum Hall effect and the spin-reversed quasiparticles

Abstract
The elementary excitations at (1/3)-Landau-level filling have been studied for various spin polarizations by finite-size calculations in a periodic rectangular geometry. For low magnetic fields, the spin-reversed quasiparticles carrying fractional electron charge are found to be important. The Zeeman energy due to the spin flip explains qualitatively the linear magnetic field dependence of the activation energies observed experimentally.