2001/04/30 by D. Bernard, Denis Bernard, Nicolas Regnault +3
Physics and Astronomy · #Quantum and electron transport phenomena #Quantum chaos and dynamical systems #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1016/s0550-3213(01)00352-2
published as Nucl.Phys. B 612 (3) (2001) 291-312 · 29 pages; few references added, statement about the density of states improved; published version
openalex publication_date 2001/10/01 · arxiv created 2001/10/08 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We introduce a large N version of the spin quantum Hall transition problem. It is formulated as a problem of Dirac fermions coupled to disorder, whose Hamiltonian belong to the symmetry class C. The fermions carry spin degrees of freedom valued in the algebra sp(2N), the spin quantum Hall effect corresponding to N=1. Arguments based on renormalization group transformations as well as on a sigma model formulation, valid in the large N limit, indicate the existence of a crossover as N varies. Contrary to the N=1 case, the large N models are shown to lead to localized states at zero energy. We also present a sigma model analysis for the system of Dirac fermions coupled to only sp(2N) random gauge potentials, which reproduces known exact results.