Fractional Quantum Hall Bilayers at Half-Filling: Tunneling-driven Non-Abelian Phase

TL;DR

This study demonstrates that tunneling in half-filled fractional quantum Hall bilayers can induce a transition from Abelian to non-Abelian topological order, specifically the Moore-Read Pfaffian state, using advanced numerical methods.

Contribution

It provides the first evidence of a continuous phase transition to a non-Abelian state driven by tunneling in FQH bilayers, confirmed by topological entanglement spectroscopy.

Findings

Identification of Moore-Read Pfaffian state in intermediate-tunneling regime

Continuous phase transition from Abelian to non-Abelian state

Evidence of non-Abelian order via entanglement measures

Abstract

Multicomponent quantum Hall systems with internal degrees of freedom provide a fertile ground for the emergence of exotic quantum liquids. Here we investigate the possibility of non-Abelian topological order in the half-filled fractional quantum Hall (FQH) bilayer system driven by the tunneling effect between two layers. By means of the state-of-the-art density-matrix renormalization group, we unveil "finger print" evidence of the non-Abelian Moore-Read Pfaffian state emerging in the intermediate-tunneling regime, including the ground-state degeneracy on the torus geometry and the topological entanglement spectroscopy (entanglement spectrum and topological entanglement entropy) on the spherical geometry, respectively. Remarkably, the phase transition from the previously identified Abelian $(331)$ Halperin state to the non-Abelian Moore-Read Pfaffian state is determined to be continuous, which is signaled by the continuous evolution of the universal part of the entanglement spectrum, and discontinuities in the excitation gap and the derivative of the ground-state energy. Our results not only provide a "proof-of-principle" demonstration of realizing a non-Abelian state through coupling different degrees of freedom, but also open up a possibility in FQH bilayer systems for detecting different chiral $p-$wave pairing states.