ENERGY-SPECTRA OF ANYONIC IONS AND ANYONIC EXCITONS IN FRACTIONAL QUANTUM HALL SYSTEMS

A system consisting of Ne electrons confined to a plane and a single hole on a parallel plane a distance d away is investigated in the presence of a strong magnetic field. The allowed values of the total angular momentum L are obtained by adding the hole angular momentum LH and the allowed values of LE, the angular momentum of the electron system. The values of LE can be obtained from numerical diagonalization of the Ne-electron system, or, if interactions between elementary excitations are neglected, by addition of angular momenta of Laughlin quasielectrons and quasiholes. All states of the electron-hole system resulting from a given LE form a degenerate branch of the spectrum at d=, but as d is decreased this degeneracy is removed. For d of the order of the magnetic length the electron-hole interaction invalidates the classification into clearly defined branches. © 1995 The American Physical Society.