Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Universal Spectral Correlations in Diffusive Quantum Systems   We have studied numerically several statistical properties of the spectra of
disordered electronic systems under the influence of an Aharonov Bohm flux
$\varphi$, which acts as a time--reversal symmetry breaking parameter. The
distribution of curvatures of the single electron energy levels has a modified
Lorentz form with different exponents in the GOE and GUE regime. It has
Gaussian tails in the crossover regime. The typical curvature is found to vary
as $ -E_c\ln (E_c\varphi^2/\Delta)$ ($E_c$ is the Thouless energy and $\Delta$
the mean level spacing) and to diverge at zero flux. We show that the harmonics
of the variation with $\varphi$ of single level quantities (current or
curvature) are correlated, in contradiction with the perturbative result. The
single level current correlation function is found to have a logarithmic
behavior at low flux, in contrast to the pure symmetry cases. The distribution
of single level currents is non--Gaussian in the GOE--GUE transition regime. We
find a universal relation between $g_d$, the typical slope of the levels, and
$g_c$, the width of the curvature distribution, as was proposed by Akkermans
and Montambaux. We conjecture the validity of our results for any chaotic
quantum system.

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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: eess
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int