2025/01/17 by Ali Feizmohammadi, Feizmohammadi, Ali · 2 citations
Mathematics · #Analysis of PDEs (math.AP) #FOS: Mathematics #Gas Dynamics and Kinetic Theory #Numerical methods in inverse problems
paper · pdf · doi:10.48550/arxiv.2501.10590
openalex publication_date 2025/01/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study formally determined inverse problems with passive measurements for one dimensional evolution equations where the goal is to simultaneously determine both the initial data as well as the variable coefficients in such an equation from the measurement of its solution at a fixed spatial point for a certain amount of time. This can be considered as a one-dimensional model of widely open inverse problems in photo-acoustic and thermo-acoustic tomography. We provide global uniqueness results for wave and heat equations stated on bounded or unbounded spatial intervals. Contrary to all previous related results on the subject, we do not impose any genericity assumptions on the coefficients or initial data. Our proofs are based on creating suitable links to the well understood spectral theory for 1D Schrödinger operators. In particular, in the more challenging case of a bounded spatial domain, our proof for the inverse problem partly relies on the following two ingredients, namely (i) a Paley-Wiener type theorem for Schrödinger operators due to Remling \citeRemling2002SchrdingerOA and a theorem of Levinson \citeLevinson1940 on distribution of zeros of entire functions of regular growth that together provide a quantifiable link between support of a compactly supported function and the upper density of its vanishing Schrödinger spectral modes and (ii) a result of Gesztesy and Simon \citeGesztesy1999InverseSA on partial data inverse spectral problems for reconstructing an unknown potential in a 1D Schrödinger operator from the knowledge of only a fraction of its spectrum.