Girvin-MacDonald-Platzman Collective Mode at General Filling Factors: Magneto-Roton Minimum at Half-Filled Landau Level
arXiv:cond-mat/9910460 · doi:10.1016/S0038-1098(00)00181-2
Abstract
The single mode approximation has proved useful for the excitation spectrum at $ν=1/3$. We apply it to general fractions and find that it predicts $n$ magneto-roton minima in the dispersion of the Girvin-MacDonald-Platzman collective mode for the fractional quantum Hall states at $ν=n/(2n+1)$, and one magneto-roton minimum for both the composite Fermi sea and the paired composite fermion state. Experimental relevance of the results will be considered.
5 pages, 6 figures