On Mass Gap in Type IIB Quantum Hall Solitons
  We discuss the mass gap in quantum Hall solitons (QHS) embedded in superstring theory. In particular, we give two holographic models which are obtained from D-brane configurations in type IIB superstring compactifications. The first one deals with the monolayered system in the D3/D7 brane set up. The second model corresponds to a multilayered system which is described by intersecting D5-branes wrapping a particular set of 3-cycles. In both models, we have shown that the mass gap is related to the filling factor. 
A. Belhaj, M.J.I. Khan, E.H. Saidi, A. Segui
hep-th cond-mat.str-el math-ph math.MP