Wavefunctional approach to the bilayer \nu =1 system and a possibility for a double non-chiral pseudospin liquid

TL;DR

This paper explores various wave functions for the bilayer  quantum Hall system, proposing that different phases such as vortex metal or pseudospin liquid may emerge due to quantum disordering at finite layer separation.

Contribution

It introduces candidate wave functions that describe possible disordered phases, including vortex metal and pseudospin liquid, expanding understanding of phase transitions in bilayer  systems.

Findings

Vortex metal phase may explain experimental 'imperfect superfluidity'

Pseudospin liquid could account for gapped resistances at higher temperatures

Different wave functions describe transitions from superfluid to disordered phases

Abstract

We systematically discuss candidate wave functions for the ground state of the bilayer \nu = 1 as the distance between the layers is varied. Those that describe increased intralayer correlations at finite distance show a departure from the superflid description for smaller distances. They may support finite energy meron excitations and a dissipative collective mode in the place of the Goldstone mode of the ordered phase i.e. describe a vortex metal phase, or imply even an incompressible, pseudospin liquid, behavior. Therefore they describe possible outcomes of quantum disordering at finite distance between the layers. The vortex metal phase may show up in experiments in the presence of disorder at lower temperatures and explain the observed "imperfect superfluidity", and the pseudospin liquid phase may be the cause of the thermally activated (gapped) behavior of the longitudinal and Hall resistances at higher temperatures in counterflow experiments.