IngentaConnect Spectral statistics in chiral-orthogonal disordered systems

Authors: Evangelou S.N.¹; Katsanos D.E.¹

Source: Journal of Physics A: Mathematical and General, Volume 36, Number 12, 2003 , pp. 3237-3254(18)

Publisher: Institute of Physics Publishing

Abstract:

We describe the singularities in the averaged density of states and the corresponding statistics of the energy levels in two- (2D) and three-dimensional (3D) chiral symmetric and time-reversal invariant disordered systems, realized in bipartite lattices with real off-diagonal disorder. For off-diagonal disorder of zero mean, we obtain a singular density of states in 2D which becomes much less pronounced in 3D, while the level-statistics can be described by a semi-Poisson distribution with mostly critical fractal states in 2D and Wigner surmise with mostly delocalized states in 3D. For logarithmic off-diagonal disorder of large strength, we find behaviour indistinguishable from ordinary disorder with strong localization in any dimension but in addition one-dimensional 1/|E| Dyson-like asymptotic spectral singularities. The off-diagonal disorder is also shown to enhance the propagation of two interacting particles similarly to systems with diagonal disorder. Although disordered models with chiral symmetry differ from non-chiral ones due to the presence of spectral singularities, both share the same qualitative localization properties except at the chiral symmetry point E 0 which is critical.

Language: English

Document Type: Miscellaneous

Affiliations: 1: Department of Physics, University of Ioannina, Ioannina 45110, Greece

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