Fluctuations of a holographic quantum Hall uid

We analyze the neutral spectrum of the holographic quantum Hall uid described by the D2-D8' model. As expected for a quantum Hall state, we find the system to be stable and gapped and that typically the lowest excitation mode is a magneto-roton. In addition, we find magneto-rotons in higher modes as well. We show that these magnetorotons are direct consequences of level crossings between vector and scalar modes.