Electron spectral function of an interacting two dimensional electron gas in a strong magnetic field

The electron spectral function of a 2D interacting electron system in a strong magnetic field is found to exhibit an energy gap at arbitrary filling fractions. In general, this gap is larger than the energy cost associated with a charge e excitation. At this {ν}=1/2 filling fraction, a numerical estimate of the tunneling gap is Δₜᵤₙ=(3.0±{}0.1)e²/{ε}lB for the Coulomb interaction.