2019/03/20 by Canzani, Yaiza, Galkowski, Jeffrey · 3 citations
#Analysis of PDEs (math.AP) #FOS: Mathematics #FOS: Physical sciences #Mathematical Physics (math-ph) #Spectral Theory (math.SP)
paper · doi:10.48550/arxiv.1903.08461
In this article we develop new techniques for studying concentration of Laplace eigenfunctions ϕλ as their frequency, λ, grows. The method consists of controlling ϕλ(x) by decomposing ϕλ into a superposition of geodesic beams that run through the point x. Each beam is localized in phase-space on a tube centered around a geodesic whose radius shrinks slightly slower than λ-(1)/(2). We control ϕλ(x) by the L2-mass of ϕλ on each geodesic tube and derive a purely dynamical statement through which ϕλ(x) can be studied. In particular, we obtain estimates on ϕλ(x) by decomposing the set of geodesic tubes into those that are non self-looping for time T and those that are. This approach allows for quantitative improvements, in terms of T, on the available bounds for L^∞ norms, Lp norms, pointwise Weyl laws, and averages over submanifolds.