The absorption spectrum around nu=1: evidence for a small size Skyrmion
  We measure the absorption spectrum of a two-dimensional electron system (2DES) in a GaAs quantum well in the presence of a perpendicular magnetic field. We focus on the absorption spectrum into the lowest Landau Level around nu=1. We find that the spectrum consists of bound electron-hole complexes, trion and exciton like. We show that their oscillator strength is a powerful probe of the 2DES spatial correlations. We find that near nu=1 the 2DES ground state consists of Skyrmions of small size (a few magnetic lengths). 
J. G. Groshaus, V. Umansky, H. Shtrikman, Y. Levinson and I.   Bar-Joseph