Title: Fractional quantum Hall systems near nematicity: bimetric theory, composite fermions, and Dirac brackets,
Abstract: We perform a detailed comparison of the Dirac composite fermion and the
recently proposed bimetric theory for a quantum Hall Jain states near half
filling. By tuning the composite Fermi liquid to the vicinity of a nematic
phase transition, we find that the two theories are equivalent to each other.
We verify that the single mode approximation for the response functions and the
static structure factor becomes reliable near the phase transition. We show
that the dispersion relation of the nematic mode near the phase transition can
be obtained from the Dirac brackets between the components of the nematic order
parameter. The dispersion is quadratic at low momenta and has a magnetoroton
minimum at a finite momentum, which is not related to any nearby inhomogeneous
phase.