1999/03/22 by Martin R. Zirnbauer, Zirnbauer, Martin R. · 1 citation
Mathematics · Physics and Astronomy · #Advanced Operator Algebra Research #Quantum Mechanics and Applications #Quantum many-body systems #cond-mat.mes-hall
paper · pdf · doi:10.48550/arxiv.cond-mat/9903338
LateX, 21 pages, no figures
arxiv created 1999/03/22 · arxiv updated 2009/11/30
Kamenev and Mezard, and Yurkevich and Lerner, have recently shown how to reproduce the large-frequency asymptotics of the energy level correlations for disordered electron systems, by doing perturbation theory around the saddles of the compact nonlinear sigma model derived from fermionic replicas. We present a critical review of their procedure and argue that its validity is limited to the perturbative regime of large frequency. The miraculous exactness of the saddle-point answer for beta = 2 (unitary symmetry) in the universal limit, is shown to be a special feature due to the Duistermaat-Heckman theorem.