223 research outputs found
Freezing Transition in Decaying Burgers Turbulence and Random Matrix Dualities
We reveal a phase transition with decreasing viscosity at \nu=\nu_c>0
in one-dimensional decaying Burgers turbulence with a power-law correlated
random profile of Gaussian-distributed initial velocities
\sim|x-x'|^{-2}. The low-viscosity phase exhibits non-Gaussian
one-point probability density of velocities, continuously dependent on \nu,
reflecting a spontaneous one step replica symmetry breaking (RSB) in the
associated statistical mechanics problem. We obtain the low orders cumulants
analytically. Our results, which are checked numerically, are based on
combining insights in the mechanism of the freezing transition in random
logarithmic potentials with an extension of duality relations discovered
recently in Random Matrix Theory. They are essentially non mean-field in nature
as also demonstrated by the shock size distribution computed numerically and
different from the short range correlated Kida model, itself well described by
a mean field one step RSB ansatz. We also provide some insights for the finite
viscosity behaviour of velocities in the latter model.Comment: Published version, essentially restructured & misprints corrected. 6
pages, 5 figure
Large Deviations of Extreme Eigenvalues of Random Matrices
We calculate analytically the probability of large deviations from its mean
of the largest (smallest) eigenvalue of random matrices belonging to the
Gaussian orthogonal, unitary and symplectic ensembles. In particular, we show
that the probability that all the eigenvalues of an (N\times N) random matrix
are positive (negative) decreases for large N as \exp[-\beta \theta(0) N^2]
where the parameter \beta characterizes the ensemble and the exponent
\theta(0)=(\ln 3)/4=0.274653... is universal. We also calculate exactly the
average density of states in matrices whose eigenvalues are restricted to be
larger than a fixed number \zeta, thus generalizing the celebrated Wigner
semi-circle law. The density of states generically exhibits an inverse
square-root singularity at \zeta.Comment: 4 pages Revtex, 4 .eps figures included, typos corrected, published
versio
Statistics of S-matrix poles for chaotic systems with broken time reversal invariance: a conjecture
In the framework of a random matrix description of chaotic quantum scattering
the positions of matrix poles are given by complex eigenvalues of an
effective non-Hermitian random-matrix Hamiltonian. We put forward a conjecture
on statistics of for systems with broken time-reversal invariance and
verify that it allows to reproduce statistical characteristics of Wigner time
delays known from independent calculations. We analyze the ensuing two-point
statistical measures as e.g. spectral form factor and the number variance. In
addition we find the density of complex eigenvalues of real asymmetric matrices
generalizing the recent result by Efetov\cite{Efnh}.Comment: 4 page
Extreme Value Statistics of Eigenvalues of Gaussian Random Matrices
We compute exact asymptotic results for the probability of the occurrence of
large deviations of the largest (smallest) eigenvalue of random matrices
belonging to the Gaussian orthogonal, unitary and symplectic ensembles. In
particular, we show that the probability that all the eigenvalues of an (NxN)
random matrix are positive (negative) decreases for large N as ~\exp[-\beta
\theta(0) N^2] where the Dyson index \beta characterizes the ensemble and the
exponent \theta(0)=(\ln 3)/4=0.274653... is universal. We compute the
probability that the eigenvalues lie in the interval [\zeta_1,\zeta_2] which
allows us to calculate the joint probability distribution of the minimum and
the maximum eigenvalue. As a byproduct, we also obtain exactly the average
density of states in Gaussian ensembles whose eigenvalues are restricted to lie
in the interval [\zeta_1,\zeta_2], thus generalizing the celebrated Wigner
semi-circle law to these restricted ensembles. It is found that the density of
states generically exhibits an inverse square-root singularity at the location
of the barriers. These results are confirmed by numerical simulations.Comment: 17 pages Revtex, 5 .eps figures include
On the distribution of maximum value of the characteristic polynomial of GUE random matrices
Motivated by recently discovered relations between logarithmically correlated Gaussian processes and characteristic polynomials of large random NĂN matrices H from the Gaussian Unitary Ensemble (GUE), we consider the problem of characterising the distribution of the global maximum of DN(x):=âlog|det(xIâH)| as Nââ and xâ(â1,1). We arrive at an explicit expression for the asymptotic probability density of the (appropriately shifted) maximum by combining the rigorous Fisher-Hartwig asymptotics due to Krasovsky \cite{K07} with the heuristic {\it freezing transition} scenario for logarithmically correlated processes. Although the general idea behind the method is the same as for the earlier considered case of the Circular Unitary Ensemble, the present GUE case poses new challenges. In particular we show how the conjectured {\it self-duality} in the freezing scenario plays the crucial role in our selection of the form of the maximum distribution. Finally, we demonstrate a good agreement of the found probability density with the results of direct numerical simulations of the maxima of DN(x)
Systematic Analytical Approach to Correlation Functions of Resonances in Quantum Chaotic Scattering
We solve the problem of resonance statistics in systems with broken
time-reversal invariance by deriving the joint probability density of all
resonances in the framework of a random matrix approach and calculating
explicitly all n-point correlation functions in the complex plane. As a
by-product, we establish the Ginibre-like statistics of resonances for many
open channels. Our method is a combination of Itzykson-Zuber integration and a
variant of nonlinear model and can be applied when the use of
orthogonal polynomials is problematic.Comment: 4 pages, no figures. Misprints corrected, some details on
single-channel and many-channel cases are adde
The Statistics of the Number of Minima in a Random Energy Landscape
We consider random energy landscapes constructed from d-dimensional lattices
or trees. The distribution of the number of local minima in such landscapes
follows a large deviation principle and we derive the associated law exactly
for dimension 1. Also of interest is the probability of the maximum possible
number of minima; this probability scales exponentially with the number of
sites. We calculate analytically the corresponding exponent for the Cayley tree
and the two-leg ladder; for 2 to 5 dimensional hypercubic lattices, we compute
the exponent numerically and compare to the Cayley tree case.Comment: 18 pages, 8 figures, added background on landscapes and reference
Imaginary Potential as a Counter of Delay Time for Wave Reflection from a 1D Random Potential
We show that the delay time distribution for wave reflection from a
one-dimensional random potential is related directly to that of the reflection
coefficient, derived with an arbitrarily small but uniform imaginary part added
to the random potential. Physically, the reflection coefficient, being
exponential in the time dwelt in the presence of the imaginary part, provides a
natural counter for it. The delay time distribution then follows
straightforwardly from our earlier results for the reflection coefficient, and
coincides with the distribution obtained recently by Texier and Comtet
[C.Texier and A. Comtet, Phys.Rev.Lett. {\bf 82}, 4220 (1999)],with all moments
infinite. Delay time distribution for a random amplifying medium is then
derived . In this case, however, all moments work out to be finite.Comment: 4 pages, RevTeX, replaced with added proof, figure and references. To
appear in Phys. Rev. B Jan01 200
On the Largest Singular Values of Random Matrices with Independent Cauchy Entries
We apply the method of determinants to study the distribution of the largest
singular values of large real rectangular random matrices with
independent Cauchy entries. We show that statistical properties of the
(rescaled by a factor of \frac{1}{m^2\*n^2})largest singular values agree in
the limit with the statistics of the inhomogeneous Poisson random point process
with the intensity and, therefore, are different
from the Tracy-Widom law. Among other corollaries of our method we show an
interesting connection between the mathematical expectations of the
determinants of complex rectangular standard Wishart ensemble
and real rectangular standard Wishart ensemble.Comment: We have shown in the revised version that the statistics of the
largest eigenavlues of a sample covariance random matrix with i.i.d. Cauchy
entries agree in the limit with the statistics of the inhomogeneous Poisson
random point process with the intensity $\frac{1}{\pi} x^{-3/2}.
Counting function fluctuations and extreme value threshold in multifractal patterns: the case study of an ideal noise
To understand the sample-to-sample fluctuations in disorder-generated
multifractal patterns we investigate analytically as well as numerically the
statistics of high values of the simplest model - the ideal periodic
Gaussian noise. By employing the thermodynamic formalism we predict the
characteristic scale and the precise scaling form of the distribution of number
of points above a given level. We demonstrate that the powerlaw forward tail of
the probability density, with exponent controlled by the level, results in an
important difference between the mean and the typical values of the counting
function. This can be further used to determine the typical threshold of
extreme values in the pattern which turns out to be given by
with . Such observation provides a
rather compelling explanation of the mechanism behind universality of .
Revealed mechanisms are conjectured to retain their qualitative validity for a
broad class of disorder-generated multifractal fields. In particular, we
predict that the typical value of the maximum of intensity is to be
given by , where is the
corresponding singularity spectrum vanishing at . For the
noise we also derive exact as well as well-controlled approximate
formulas for the mean and the variance of the counting function without
recourse to the thermodynamic formalism.Comment: 28 pages; 7 figures, published version with a few misprints
corrected, editing done and references adde
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