51 research outputs found
SPECTRAL CORRELATIONS IN DISORDERED ELECTRONIC SYSTEMS: CROSSOVER FROM METAL TO INSULATOR REGIME
We use the semiclassical approach combined with the scaling results for the
diffusion coefficient to consider the two-level correlation function
for a disordered electron system in the crossover region,
characterized by the appearance of a macroscopic correlation or localization
length, , that diverges at the metal-insulator transition. We show new
critical statistics, characterized by a nontrivial asymptotic behavior of
, to emerge on both sides of the transition at higher energies,
and to expand to all energies larger than mean level spacing when exceeds
the system size.Comment: 4 pages,1 figure, in self-ectracting uuencoded gz-compressed file to
be published in Phys. Rev. Letters; REVTeX source file is available upon
reques
Multiphoton Processes in Driven Mesoscopic Systems
We study the statistics of multi-photon absorption/emission processes in a
mesoscopic ring threaded by an harmonic time-dependent flux . For this
sake, we demonstrate a useful analogy between the Keldysh quantum kinetic
equation for the electrons distribution function and a Continuous Time Random
Walk in energy space with corrections due to interference effects. Studying the
probability to absorb/emit quanta per scattering event, we
explore the crossover between ultra-quantum/low-intensity limit and
quasi-classical/high-intensity regime, and the role of multiphoton processes in
driving it.Comment: 6 pages, 5 figures, extended versio
One-dimensional Anderson Localization: Devil's staircase of Statistical Anomalies
The statistics of wavefunctions in the one-dimensional (1d) Anderson model of
localization is considered. It is shown that at any energy that corresponds to
a rational filling factor f=p/q there is a statistical anomaly which is seen in
expansion of the generating function (GF) to the order (q-2) in the disorder
parameter. We study in detail the principle anomaly at that appears in
the leading order. The transfer-matrix equation of the Fokker-Planck type with
a two-dimensional internal space is derived for GF. It is shown that the
zero-mode variant of this equation is integrable and a solution for the
generating function is found in the thermodynamic limit.Comment: 4 pages RevTex, 1 pictur
Energy level statistics of a critical random matrix ensemble
We study level statistics of a critical random matrix ensemble of a power-law
banded complex Hermitean matrices. We compute numerically the level
compressibility via the level number variance and compare it with the
analytical formula for the exactly solvable model of Moshe, Neuberger and
Shapiro.Comment: 8 pages, 3 figure
- …