Bimetric Theory of Fractional Quantum Hall States

I will describe the recently developed bimetric theory of fractional quantum Hall states. This effective theory includes the Chern-Simons theory that describes the topological properties of the fractional quantum Hall states and a la quantum bimetric gravity theory that describes the massive Girvin-MacDonald-Platzman mode at long wavelengths. The theory reproduces universal features of the chiral lowest Landau level (LLL) FQH states that lie beyond the reach of pure Chern-Simons theory, such as the projected static structure factor and the GMP algebra. The LLL projection and particle-hole ``symmetry'' of the theory are particularly transparent. Familiar quantum Hall observables acquire a curious geometric interpretation in the bimetric language.