328 research outputs found
Topological expansion and boundary conditions
In this article, we compute the topological expansion of all possible
mixed-traces in a hermitian two matrix model. In other words we give a recipe
to compute the number of discrete surfaces of given genus, carrying an Ising
model, and with all possible given boundary conditions. The method is
recursive, and amounts to recursively cutting surfaces along interfaces. The
result is best represented in a diagrammatic way, and is thus rather simple to
use.Comment: latex, 25 pages. few misprints correcte
Loop equations for the semiclassical 2-matrix model with hard edges
The 2-matrix models can be defined in a setting more general than polynomial
potentials, namely, the semiclassical matrix model. In this case, the
potentials are such that their derivatives are rational functions, and the
integration paths for eigenvalues are arbitrary homology classes of paths for
which the integral is convergent. This choice includes in particular the case
where the integration path has fixed endpoints, called hard edges. The hard
edges induce boundary contributions in the loop equations. The purpose of this
article is to give the loop equations in that semicassical setting.Comment: Latex, 20 page
Non-homogenous disks in the chain of matrices
We investigate the generating functions of multi-colored discrete disks with
non-homogenous boundary conditions in the context of the Hermitian multi-matrix
model where the matrices are coupled in an open chain. We show that the study
of the spectral curve of the matrix model allows one to solve a set of loop
equations to get a recursive formula computing mixed trace correlation
functions to leading order in the large matrix limit.Comment: 25 pages, 4 figure
Topological expansion of beta-ensemble model and quantum algebraic geometry in the sectorwise approach
We solve the loop equations of the -ensemble model analogously to the
solution found for the Hermitian matrices . For \beta=1y^2=U(x)\beta((\hbar\partial)^2-U(x))\psi(x)=0\hbar\propto
(\sqrt\beta-1/\sqrt\beta)/Ny^2-U(x)[y,x]=\hbarF_h-expansion at arbitrary . The set of "flat"
coordinates comprises the potential times and the occupation numbers
\widetilde{\epsilon}_\alpha\mathcal F_0\widetilde{\epsilon}_\alpha$.Comment: 58 pages, 7 figure
Mixed Correlation Functions of the Two-Matrix Model
We compute the correlation functions mixing the powers of two non-commuting
random matrices within the same trace. The angular part of the integration was
partially known in the literature: we pursue the calculation and carry out the
eigenvalue integration reducing the problem to the construction of the
associated biorthogonal polynomials. The generating function of these
correlations becomes then a determinant involving the recursion coefficients of
the biorthogonal polynomials.Comment: 16 page
Matrix eigenvalue model: Feynman graph technique for all genera
We present the diagrammatic technique for calculating the free energy of the
matrix eigenvalue model (the model with arbitrary power by the
Vandermonde determinant) to all orders of 1/N expansion in the case where the
limiting eigenvalue distribution spans arbitrary (but fixed) number of disjoint
intervals (curves).Comment: Latex, 27 page
Double scaling limits of random matrices and minimal (2m,1) models: the merging of two cuts in a degenerate case
In this article, we show that the double scaling limit correlation functions
of a random matrix model when two cuts merge with degeneracy (i.e. when
for arbitrary values of the integer ) are the same as the
determinantal formulae defined by conformal models. Our approach
follows the one developed by Berg\`{e}re and Eynard in \cite{BergereEynard} and
uses a Lax pair representation of the conformal models (giving
Painlev\'e II integrable hierarchy) as suggested by Bleher and Eynard in
\cite{BleherEynard}. In particular we define Baker-Akhiezer functions
associated to the Lax pair to construct a kernel which is then used to compute
determinantal formulae giving the correlation functions of the double scaling
limit of a matrix model near the merging of two cuts.Comment: 37 pages, 4 figures. Presentation improved, typos corrected.
Published in Journal Of Statistical Mechanic
All genus correlation functions for the hermitian 1-matrix model
We rewrite the loop equations of the hermitian matrix model, in a way which
allows to compute all the correlation functions, to all orders in the
topological expansion, as residues on an hyperelliptical curve. Those
residues, can be represented diagrammaticaly as Feynmann graphs of a cubic
interaction field theory on the curve.Comment: latex, 19 figure
Large deviations of the maximal eigenvalue of random matrices
We present detailed computations of the 'at least finite' terms (three
dominant orders) of the free energy in a one-cut matrix model with a hard edge
a, in beta-ensembles, with any polynomial potential. beta is a positive number,
so not restricted to the standard values beta = 1 (hermitian matrices), beta =
1/2 (symmetric matrices), beta = 2 (quaternionic self-dual matrices). This
model allows to study the statistic of the maximum eigenvalue of random
matrices. We compute the large deviation function to the left of the expected
maximum. We specialize our results to the gaussian beta-ensembles and check
them numerically. Our method is based on general results and procedures already
developed in the literature to solve the Pastur equations (also called "loop
equations"). It allows to compute the left tail of the analog of Tracy-Widom
laws for any beta, including the constant term.Comment: 62 pages, 4 figures, pdflatex ; v2 bibliography corrected ; v3 typos
corrected and preprint added ; v4 few more numbers adde
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