1,712 research outputs found
Autocorrelations of the characteristic polynomial of a random matrix under microscopic scaling
We calculate the autocorrelation function for the characteristic polynomial
of a random matrix in the microscopic scaling regime. While results fitting
this description have be proved before, we will cover all values of inverse
temperature . The method also differs from prior work,
relying on matrix models introduced by Killip and Nenciu
Matrix models for circular ensembles
We describe an ensemble of (sparse) random matrices whose eigenvalues follow
the Gibbs distribution for n particles of the Coulomb gas on the unit circle at
inverse temperature beta. Our approach combines elements from the theory of
orthogonal polynomials on the unit circle with ideas from recent work of
Dumitriu and Edelman. In particular, we resolve a question left open by them:
find a tri-diagonal model for the Jacobi ensemble.Comment: 28 page
Smooth solutions to the nonlinear wave equation can blow up on Cantor sets
We construct solutions to the one-dimensional nonlinear wave
equation that blow up on any prescribed uniformly space-like
hypersurface. As a corollary, we show that smooth solutions can blow up (at the
first instant) on an arbitrary compact set.
We also construct solutions that blow up on general space-like
hypersurfaces, but only when is not an integer and
Sum Rules for Jacobi Matrices and Their Applications to Spectral Theory
We discuss the proof of and systematic application of Case's sum rules for
Jacobi matrices. Of special interest is a linear combination of two of his sum
rules which has strictly positive terms. Among our results are a complete
classification of the spectral measures of all Jacobi matrices J for which
J-J_0 is Hilbert--Schmidt, and a proof of Nevai's conjecture that the Szego
condition holds if J-J_0 is trace class.Comment: 69 pages, published versio
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