High Energy Theory Seminar

In this talk I will discuss an effective field theory treatment of the fractional quantum Hall effect, mostly focusing on states with filling fraction in the interval [0,1]. The starting point is an improved version of Son's Dirac composite fermion theory proposed by Seiberg, Senthil, Wang, and Witten (SSWW). Son's original theory was designed to model the half-filled Landau level, and the SSWW version is an improvement such that its gapped states with filling fraction 0 and 1 are topologically trivial. Using some field theory tools, including three-dimensional dualities, I will (1) obtain perturbative effective field theory descriptions from the SSWW theory of gapless states at even-denominator filling fractions, given by a Fermi surface coupled to a suitable Chern-Simons theory, and (2) find a complicated landscape of vacua that faithfully reproduces the Jain hierarchy of FQH states. In this analysis three-dimensional dualities effectively play the role of flux attachment. Moreover, in effective field theory, the gapless description of even-denominator filling, like 1/4 or 3/4, admits superconducting instabilities, leading to non-abelian gapped states analogous to the T-Pfaffian state at half-filling. By adding spectator filled Landau levels this gives us a theory of non-abelian even-denominator states with filling fraction >1.

The talk is in 469 Lauritsen.

Contact theoryinfo@caltech.edu for Zoom information.