Speaker: Dr. Andrey Gromov, Brown University, USA
Title: Bimetric theory of fractional quantum Hall states
Abstract: Fractional quantum Hall (FQH) states are topologically ordered. Additionally, FQH states support a collective neutral excitation known as the Girvin-MacDonald-Platzman (GMP) mode. Certain features of this mode are independent of the microscopic details. The objective of the talk is to provide a pedagogical introduction into the physics of this collective mode, and construct an effective theory includes both topological properties and the massive GMP mode. The theory reproduces the universal properties of chiral lowest Landau level (LLL) FQH states which lie beyond the TQFT data, such as the projected static structure factor and the GMP algebra of area-preserving diffeomorphisms. The dynamics of the mode is described by a fluctuating rank-2 symmetric, positive-definite tensor, which leads to a natural geometric (or gravitational) interpretation of the GMP mode.