Competing ν = 5/2 fractional quantum Hall states in confined geometry

Hailong Fu, Pengjie Wang, Pujia Shan, Lin Xiong, Loren N. Pfeiffer, Ken West, Marc A. Kastner, Xi Lin

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Some theories predict that the filling factor 5/2 fractional quantum Hall state can exhibit non-Abelian statistics, which makes it a candidate for fault-tolerant topological quantum computation. Although the non-Abelian Pfaffian state and its particle-hole conjugate, the anti-Pfaffian state, are the most plausible wave functions for the 5/2 state, there are a number of alternatives with either Abelian or non-Abelian statistics. Recent experiments suggest that the tunneling exponents are more consistent with an Abelian state rather than a non-Abelian state. Here, we present edge-current-tunneling experiments in geometrically confined quantum point contacts, which indicate that Abelian and non-Abelian states compete at filling factor 5/2. Our results are consistent with a transition from an Abelian state to a non-Abelian state in a single quantum point contact when the confinement is tuned. Our observation suggests that there is an intrinsic non-Abelian 5/2 ground state but that the appropriate confinement is necessary to maintain it. This observation is important not only for understanding the physics of the 5/2 state but also for the design of future topological quantum computation devices.

Original languageEnglish (US)
Pages (from-to)12386-12390
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
StatePublished - Nov 1 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


  • 5/2 fractional quantum Hall state
  • Edge-current tunneling
  • Fractional quantum Hall effect
  • Non-Abelian statistics
  • Quantum point contact


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