A continuous transition between fractional quantum Hall and superfluid states

TL;DR

This paper proposes a theoretical framework for a continuous quantum phase transition between a bosonic fractional quantum Hall state and a superfluid, involving Dirac fermions and Chern-Simons gauge fields, with potential realization in ultracold atom experiments.

Contribution

It introduces a novel critical theory describing a direct transition between FQH and superfluid states, extending phase diagrams to include time-reversal symmetry breaking.

Findings

Critical theory involves Dirac fermions coupled to Chern-Simons gauge field.

Transition can be protected by spatial symmetry.

Potential experimental realization with ultracold atoms.

Abstract

We develop a theory of a direct, continuous quantum phase transition between a bosonic Laughlin fractional quantum Hall (FQH) state and a superfluid, generalizing the Mott insulator to superfluid phase diagram of bosons to allow for the breaking of time-reversal symmetry. The direct transition can be protected by a spatial symmetry, and the critical theory is a pair of Dirac fermion fields coupled to an emergent Chern-Simons gauge field. The transition may be achieved in optical traps of ultracold atoms by starting with a $\nu = 1/2$ bosonic Laughlin state and tuning an appropriate periodic potential to change the topology of the composite fermion band structure.