Linear optical responses of one-dimensional electron systems: Comparison of theories with experiments

We present a systematic study on the linear optical spectra of n-doped GaAs quantum wire. A Coulomb-correlated band-edge absorption peak appears at low doping density evolving from the exciton resonance. The Fermi-edge singularity is observed at high doping density. Based on theoretical calculations, we clarify the mechanism of the crossover among exciton, the band-edge and the Fermi-edge singularities.