40 research outputs found
Asymptotics of a Class of Solutions to the Cylindrical Toda Equations
The small t asymptotics of a class of solutions to the 2D cylindrical Toda
equations is computed. The solutions, q_k(t), have the representation q_k(t) =
log det(I-lambda K_k) - log det(I-lambda K_{k-1}) where K_k are integral
operators. This class includes the n-periodic cylindrical Toda equations. For
n=2 our results reduce to the previously computed asymptotics of the 2D radial
sinh-Gordon equation and for n=3 (and with an additional symmetry contraint)
they reduce to earlier results for the radial Bullough-Dodd equation.Comment: 29 pages, no figures, LaTeX fil
Proofs of Two Conjectures Related to the Thermodynamic Bethe Ansatz
We prove that the solution to a pair of nonlinear integral equations arising
in the thermodynamic Bethe Ansatz can be expressed in terms of the resolvent
kernel of the linear integral operator with kernel
exp(-u(theta)-u(theta'))/cosh[(1/2)(theta-theta')]Comment: 16 pages, LaTeX file, no figures. Revision has minor change
On the Distribution of a Second Class Particle in the Asymmetric Simple Exclusion Process
We give an exact expression for the distribution of the position X(t) of a
single second class particle in the asymmetric simple exclusion process (ASEP)
where initially the second class particle is located at the origin and the
first class particles occupy the sites {1,2,...}
Higher Order Analogues of Tracy-Widom Distributions via the Lax Method
We study the distribution of the largest eigenvalue in formal Hermitian
one-matrix models at multicriticality, where the spectral density acquires an
extra number of k-1 zeros at the edge. The distributions are directly expressed
through the norms of orthogonal polynomials on a semi-infinite interval, as an
alternative to using Fredholm determinants. They satisfy non-linear recurrence
relations which we show form a Lax pair, making contact to the string
literature in the early 1990's. The technique of pseudo-differential operators
allows us to give compact expressions for the logarithm of the gap probability
in terms of the Painleve XXXIV hierarchy. These are the higher order analogues
of the Tracy-Widom distribution which has k=1. Using known Backlund
transformations we show how to simplify earlier equivalent results that are
derived from Fredholm determinant theory, valid for even k in terms of the
Painleve II hierarchy.Comment: 24 pages. Improved discussion of Backlund transformations, in
addition to other minor improvements in text. Typos corrected. Matches
published versio
On the Linearization of the First and Second Painleve' Equations
We found Fuchs--Garnier pairs in 3X3 matrices for the first and second
Painleve' equations which are linear in the spectral parameter. As an
application of our pairs for the second Painleve' equation we use the
generalized Laplace transform to derive an invertible integral transformation
relating two its Fuchs--Garnier pairs in 2X2 matrices with different
singularity structures, namely, the pair due to Jimbo and Miwa and the one
found by Harnad, Tracy, and Widom. Together with the certain other
transformations it allows us to relate all known 2X2 matrix Fuchs--Garnier
pairs for the second Painleve' equation with the original Garnier pair.Comment: 17 pages, 2 figure
Asymptotic Level Spacing of the Laguerre Ensemble: A Coulomb Fluid Approach
We determine the asymptotic level spacing distribution for the Laguerre
Ensemble in a single scaled interval, , containing no levels,
E_{\bt}(0,s), via Dyson's Coulomb Fluid approach. For the
Unitary-Laguerre Ensemble, we recover the exact spacing distribution found by
both Edelman and Forrester, while for , the leading terms of
, found by Tracy and Widom, are reproduced without the use of the
Bessel kernel and the associated Painlev\'e transcendent. In the same
approximation, the next leading term, due to a ``finite temperature''
perturbation (\bt\neq 2), is found.Comment: 10pp, LaTe
Spectra of massive and massless QCD Dirac operators: A novel link
We show that integrable structure of chiral random matrix models incorporating global symmetries of QCD Dirac operators (labeled by the Dyson index beta=1,2, and 4) leads to emergence of a connection relation between the spectral statistics of massive and massless Dirac operators. This novel link established for beta-fold degenerate massive fermions is used to explicitly derive (and prove the random matrix universality of) statistics of low--lying eigenvalues of QCD Dirac operators in the presence of SU(2) massive fermions in the fundamental representation (beta=1) and SU(N_c >= 2) massive adjoint fermions (beta=4). Comparison with available lattice data for SU(2) dynamical staggered fermions reveals a good agreement
A pedestrian's view on interacting particle systems, KPZ universality, and random matrices
These notes are based on lectures delivered by the authors at a Langeoog
seminar of SFB/TR12 "Symmetries and universality in mesoscopic systems" to a
mixed audience of mathematicians and theoretical physicists. After a brief
outline of the basic physical concepts of equilibrium and nonequilibrium
states, the one-dimensional simple exclusion process is introduced as a
paradigmatic nonequilibrium interacting particle system. The stationary measure
on the ring is derived and the idea of the hydrodynamic limit is sketched. We
then introduce the phenomenological Kardar-Parisi-Zhang (KPZ) equation and
explain the associated universality conjecture for surface fluctuations in
growth models. This is followed by a detailed exposition of a seminal paper of
Johansson that relates the current fluctuations of the totally asymmetric
simple exclusion process (TASEP) to the Tracy-Widom distribution of random
matrix theory. The implications of this result are discussed within the
framework of the KPZ conjecture.Comment: 52 pages, 4 figures; to appear in J. Phys. A: Math. Theo
Slow decorrelations in KPZ growth
For stochastic growth models in the Kardar-Parisi-Zhang (KPZ) class in 1+1
dimensions, fluctuations grow as t^{1/3} during time t and the correlation
length at a fixed time scales as t^{2/3}. In this note we discuss the scale of
time correlations. For a representant of the KPZ class, the polynuclear growth
model, we show that the space-time is non-trivially fibred, having slow
directions with decorrelation exponent equal to 1 instead of the usual 2/3.
These directions are the characteristic curves of the PDE associated to the
surface's slope. As a consequence, previously proven results for space-like
paths will hold in the whole space-time except along the slow curves.Comment: 22 pages, 9 figures, LaTeX; Minor language revision
Breaking supersymmetry in a one-dimensional random Hamiltonian
The one-dimensional supersymmetric random Hamiltonian
, where is a Gaussian white
noise of zero mean and variance , presents particular spectral and
localization properties at low energy: a Dyson singularity in the integrated
density of states (IDoS) and a delocalization transition
related to the behaviour of the Lyapunov exponent (inverse localization length)
vanishing like as . We study how this picture
is affected by breaking supersymmetry with a scalar random potential:
where is a Gaussian white noise of variance .
In the limit , a fraction of states
migrate to the negative spectrum and the
Lyapunov exponent reaches a finite value at
E=0. Exponential (Lifshits) tail of the IDoS for is studied in
detail and is shown to involve a competition between the two noises and
whatever the larger is. This analysis relies on analytic results for
and obtained by two different methods: a stochastic method and the
replica method. The problem of extreme value statistics of eigenvalues is also
considered (distribution of the n-th excited state energy). The results are
analyzed in the context of classical diffusion in a random force field in the
presence of random annihilation/creation local rates.Comment: 33 pages, LaTeX, 13 eps figures ; 2nd version : refs. adde