title: Higher-energy composite fermion levels in the fractional quantum Hall effect.
abstract: Even though composite fermions in the fractional quantum Hall liquid are well established, it is not yet known up to what energies they remain intact. We probe the high-energy spectrum of the 1/3 liquid directly by resonant inelastic light scattering, and report the observation of a large number of new collective modes. Supported by our theoretical calculations, we associate these with transitions across two or more composite fermions levels. The formation of quasiparticle levels up to high energies is direct evidence for the robustness of topological order in the fractional quantum Hall effect.
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.
authors.forename: Trevor D
authors.initials: TD
authors.lastname: Rhone
authors.forename: Dwipesh
authors.initials: D
authors.lastname: Majumder
authors.forename: Brian S
authors.initials: BS
authors.lastname: Dennis
authors.forename: Cyrus
authors.initials: C
authors.lastname: Hirjibehedin
authors.forename: Irene
authors.initials: I
authors.lastname: Dujovne
authors.forename: Javier G
authors.initials: JG
authors.lastname: Groshaus
authors.forename: Yann
authors.initials: Y
authors.lastname: Gallais
authors.forename: Jainendra K
authors.initials: JK
authors.lastname: Jain
authors.forename: Sudhansu S
authors.initials: SS
authors.lastname: Mandal
authors.forename: Aron
authors.initials: A
authors.lastname: Pinczuk
authors.forename: Loren
authors.initials: L
authors.lastname: Pfeiffer
authors.forename: Ken
authors.initials: K
authors.lastname: West