Abstract

We propose an effective field theory (EFT) of fractional quantum Hall systems near the filling fraction $\nu=5/2$ that flows to pertinent IR candidate phases, including non-abelian Pfaffian, anti-Pfaffian, and particle-hole Pfaffian states (Pf, APf, and PHPf). Our EFT has a 2+1$d$ O(2)$_{2,L}$ Chern-Simons gauge theory coupled to four Majorana fermions by a discrete charge conjugation gauge field, with Gross-Neveu-Yukawa-Higgs terms. Including deformations via a Higgs condensate and fermion mass terms, we can map out a phase diagram with tunable parameters, reproducing the prediction of the recently-proposed percolation picture and its gapless topological quantum phase transitions. Our EFT captures known features of both gapless and gapped sectors of time-reversal-breaking domain walls between Pf and APf phases. Moreover, we find that Pf$\mid$APf domain walls have higher tension than domain walls in the PHPf phase. Then the former, if formed, may transition to the energetically-favored PHPf domain walls; this could, in turn, help further induce a bulk transition to PHPf.

Highlights

  • One of the first non-Abelian topologically ordered candidate states was observed experimentally in 1987 [1]

  • We propose a unified bulk effective field theory (EFT) that gives rise to various topological quantum field theories (TQFTs) and their edge modes pertinent to the ν = 5/2 fractional quantum Hall (fQH) system

  • The first question to ask about our EFT equation (4) is as follows: Why do we introduce two Dirac fermions? This can be understood from solving the Bogoliubov–de Gennes (BdG) equation [15], which allows us to analyze the gap function (k, r) around the domain wall between the Pf and APf regions

Read more

Summary

INTRODUCTION

One of the first non-Abelian topologically ordered candidate states was observed experimentally in 1987 [1]. It is the filling fraction ν = 5/2 fractional quantum Hall (fQH) state of an interacting electron gas in 2 + 1 space-time dimensions [denoted as (2 + 1)D]. It has a fractional quantized Hall conductance σxy = 5/2 in units of e2/h where e is the electron charge and h is the Planck constant. We first recall pertinent proposals from the literature

Overview of theoretical proposals and questions
Comparison of three related proposals on disordered percolating systems
Outline
From gapless or gapped Fermi surfaces to four gapless Majorana nodes
Random coupling and the thermal metal phase
ANYONIC EXCITATIONS AND QUANTUM
DOMAIN WALL THEORY AND TENSION
Fermionic zero modes in the domain wall background
One-loop effective action and tension
Domain wall tension
Effect of gauging
CONCLUSION AND FUTURE DIRECTIONS
Hall conductivity
Quantum numbers of quasiexcitations
Fermionic functional determinant
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call