Neutral excitation and bulk gap of fractional quantum Hall liquids in disk geometry
Yang Wu-Qing1, Li Qi2, 3, Yang Lin-Peng1, Hu Zi-Xiang1, †
       

The magneto-roton spectrum on disk (a), sphere (b), and torus (c) for V1 Hamiltonian. The energy gap is labeled by the difference between ground state and the roton minimum.