English

$(1+\varepsilon)$-moments suffice to characterise the GFF

Probability 2020-12-10 v2

Abstract

We show that there is "no stable free field of index α(1,2)\alpha\in (1,2)", in the following sense. It was proved in a previous work by the authors, that subject to a \emph{fourth moment assumption}, any random generalised function on a domain DD of the plane, satisfying conformal invariance and a natural domain Markov property, must be a constant multiple of the Gaussian free field. In this article we show that the existence of (1+ε)(1+\varepsilon)-moments is sufficient for the same conclusion. A key idea is a new way of exploring the field, where (instead of looking at the more standard circle averages) we start from the boundary and discover averages of the field with respect to a certain "hitting density" of It\^o excursions.

Keywords

Cite

@article{arxiv.2005.02349,
  title  = {$(1+\varepsilon)$-moments suffice to characterise the GFF},
  author = {Nathanaël Berestycki and Ellen Powell and Gourab Ray},
  journal= {arXiv preprint arXiv:2005.02349},
  year   = {2020}
}