English

On the growth of generalized Fourier coefficients of restricted eigenfunctions

Analysis of PDEs 2022-04-06 v1

Abstract

Let (M,g)(M,g) be a smooth, compact, Riemannian manifold and {ϕh}\{\phi_h\} a sequence of L2L^2-normalized Laplace eigenfunctions on MM. For a smooth submanifold HMH\subset M, we consider the growth of the restricted eigenfunctions ϕhH\phi_h|_H by testing them against a sequence of functions {ψh}\{\psi_h\} on HH whose wavefront set avoids SHS^*H. That is, we study what we call the generalized Fourier coefficients: ϕh,ψhL2(H)\langle \phi_h,\psi_h\rangle_{L^2(H)}. We give an explicit bound on these coefficients depending on how the defect measures for the two collections of functions ϕh\phi_h and ψh\psi_h relate. This allows us to get a littleo-o improvement whenever the collection of recurrent directions over the wavefront set of ψh\psi_h is small. To obtain our estimates, we utilize geodesic beam techniques.

Keywords

Cite

@article{arxiv.2204.01881,
  title  = {On the growth of generalized Fourier coefficients of restricted eigenfunctions},
  author = {Madelyne M. Brown},
  journal= {arXiv preprint arXiv:2204.01881},
  year   = {2022}
}

Comments

25 pages, 2 figures