Waves in a random medium: Endpoint Strichartz estimates and number estimates

TL;DR

This paper investigates wave propagation in a random medium, deriving key number estimates and endpoint Strichartz estimates that could help in formulating kinetic equations, with results applicable to Schrödinger waves in Gaussian random potentials.

Contribution

It provides new number estimates in Fock space and combines endpoint Strichartz estimates with a Cauchy-Kowalevski argument for wave analysis in random media.

Findings

Accurate number estimates propagated over macroscopic times

Endpoint Strichartz estimates are crucial for analysis

Results applicable to Schrödinger waves in Gaussian potentials

Abstract

In this article we reconsider the problem of the propagation of waves in a random medium in a kinetic regime. The final aim of this program would be the understanding of the conditions which allow to derive a kinetic or radiative transfer equation. Although it is not reached for the moment, accurate and somehow surprising number estimates in the Fock space setting, which happen to be propagated by the dynamics on macroscopic time scales, are obtained. Keel and Tao endpoint Strichartz estimates play a crucial role after being combined with a Cauchy-Kowalevski type argument. Although the whole article is focussed on the simplest case of Schr{\"o}dinger waves in a gaussian random potential of which the translation into a QFT problem is straightforward, several intermediate results are written in a general setting in order to be applied to other similar problems.