24 research outputs found
Asymptotic Laws for the Spatial Distribution and the Number of Connected Components of Zero Sets of Gaussian Random Functions
We study the asymptotic laws for the spatial distribution and the number of connected components of zero sets of smooth Gaussian random functions of several real variables. The primary examples are various Gaussian ensembles of real-valued polynomials (algebraic or trigonometric) of large degree on the sphere or torus, and translation-invariant smooth Gaussian functions on the Euclidean space restricted to large domains
Zeroes of Gaussian Analytic Functions with Translation-Invariant Distribution
We study zeroes of Gaussian analytic functions in a strip in the complex
plane, with translation-invariant distribution. We prove that the a limiting
horizontal mean counting-measure of the zeroes exists almost surely, and that
it is non-random if and only if the spectral measure is continuous (or
degenerate). In this case, the mean zero-counting measure is computed in terms
of the spectral measure. We compare the behavior with Gaussian analytic
function with symmetry around the real axis. These results extend a work by
Norbert Wiener.Comment: 24 pages, 1 figure. Some corrections were made and presentation was
improve
Random wave functions and percolation
Recently it was conjectured that nodal domains of random wave functions are
adequately described by critical percolation theory. In this paper we
strengthen this conjecture in two respects. First, we show that, though wave
function correlations decay slowly, a careful use of Harris' criterion confirms
that these correlations are unessential and nodal domains of random wave
functions belong to the same universality class as non critical percolation.
Second, we argue that level domains of random wave functions are described by
the non-critical percolation model.Comment: 13 page
On the number of excursion sets of planar Gaussian fields
37 pages, 14 figures37 pages, 14 figures37 pages, 14 figure
On Nonlinear Functionals of Random Spherical Eigenfunctions
We prove Central Limit Theorems and Stein-like bounds for the asymptotic
behaviour of nonlinear functionals of spherical Gaussian eigenfunctions. Our
investigation combine asymptotic analysis of higher order moments for Legendre
polynomials and, in addition, recent results on Malliavin calculus and Total
Variation bounds for Gaussian subordinated fields. We discuss application to
geometric functionals like the Defect and invariant statistics, e.g.
polyspectra of isotropic spherical random fields. Both of these have relevance
for applications, especially in an astrophysical environment.Comment: 24 page
Lower bounds for quasianalytic functions, I. How to control smooth functions
Consider a class of functions of one real variable with the following
uniqueness property: if a function f(x) from the class vanishes on a set of
positive measure, then f is the zero function. In many instances, we would like
to have a quantitative version of this property, e.g. a lower bound for f(x)
outside a small exceptional set. Such estimates are well-known and useful for
polynomials and analytic functions. In this work we prove similar results for
the Denjoy-Carleman and the Bernstein classes of quasianalytic functions.Comment: Stylistic corrections have been mad
Lower bounds for quasianalytic functions, I. How to control smooth functions
Let be a class of functions with the uniqueness property: if vanishes on a set of positive measure, then is the zero function. In many instances, we would like to have a quantitative version of this property, e.g. the estimate from below for the norm of the restriction operator or, equivalently, a lower bound for outside a small exceptional set. Such estimates are well-known and useful for polynomials, complex- and real-analytic functions, exponential polynomials. In this work we prove similar results for the Denjoy-Carleman and the Bernstein classes of quasianalytic functions.
In the first part, we consider quasianalytically smooth functions. This part relies upon Bang's approach and includes the proofs of relevant results of Bang. In the second part, which is to be published separately, we deal with classes of functions characterized by exponentially fast approximation by polynomials whose degrees belong to a given very lacunar sequence.The proofs are based on the elementary calculus technique