The fractional quantum Hall effect (FQHE) realized in two-dimensional electron systems is explained by the emergent composite fermions (CF) out of ordinary electrons. It is possible to write down explicit wavefunctions explaining many if not all FQHE states. In bilayer systems there is a regime at integer filling of the lowest Landau level that displays a spontaneous breakdown of the U(1) relative phase between the two layers. This can be seen as interlayer phase coherence (ILC) in terms of electrons. Recent experiments in double layer samples of graphene have revealed the appearance of many FQHE states unique to the bilayer case. We discuss extensions of the CF idea in this situation as well as the possible existence of ILC of CFs.
@article{arxiv.2501.18254,
title = {Interlayer phase coherence and composite fermions},
author = {Thierry Jolicoeur},
journal= {arXiv preprint arXiv:2501.18254},
year = {2025}
}
Comments
10 pages, talk given at the workshop "open questions in the quantum many-body problem" held in Institut Henri Poincare in Paris, July 2024, organized by Y. Castin and C. Sa de Melo. More beautiful version with fancy owl logo available at the journal website (open access)