Continuous phase transitions between fractional quantum Hall states and symmetry-protected topological states

We study quantum phase transitions in Bose-Fermi mixtures driven by inter-species interaction in the quantum Hall regime. In the absence of such interaction, the bosons and fermions form their respective fractional quantum Hall (FQH) states at certain filling factors. A symmetry-protected topological (SPT) state is identified as the ground state for strong inter-species interaction. The phase transitions between them are proposed to be described by Chern-Simons-Higgs field theories. For a simple microscopic Hamiltonian, we present numerical evidence for the existence of the SPT state and a continuous transition to the FQH state. It is also found that the entanglement entropy between the bosons and fermions exhibits scaling behavior in the vicinity of this transition.
Comment: 9 pages, 5 figures