Double-exciton component of the cyclotron spin-flip mode in a quantum   Hall ferromagnet
  We report on the calculation of the cyclotron spin-flip excitation (CSFE) in a spin-polarized quantum Hall system at unit filling. This mode has a double-exciton component which contributes to the CSFE correlation energy but can not be found by means of a mean field approach. The result is compared with available experimental data. 
S. Dickmann and V.M. Zhilin