6 papers
X-ray imaging from nonlinear waves: numerical reconstruction of a cubic nonlinearity
Suvi Anttila, Markus Harju, Teemu Tyni
We study an inverse boundary value problem for the nonlinear wave equation in dimensions. The objective is to recover an unknown potential from the associated Dir…
Reconstruction for an inverse scattering problem with a Kerr type nonlinearity
Khaoula El Maddah, Matti Lassas, Tony Liimatainen +2
We study the inverse scattering problem for the Kerr-nonlinear Helmholtz equation \[ Îu + k^2(1+q(x)|u|^2)u = 0 \quad \text{in }\mathbb{R}^n,\; n\geq 2, \] where the aim is to rec…
Numerical reconstruction of Schrödinger equations with quadratic nonlinearities
Khaoula El Maddah, Matti Lassas, Teemu Tyni
We introduce a numerical framework for reconstructing the potential in two dimensional semilinear elliptic PDEs with power type nonlinearities from the nonlinear Dirichlet to Neuma…
Gaussian beam interactions and inverse source problems for nonlinear wave equations
Matti Lassas, Tony Liimatainen, Valter Pohjola +1
We study the inverse source problem for the semilinear wave equation \[ (\Box_g + q_1)u + q_2 u^2 = F, \] on a globally hyperbolic Lorentzian manifold. We demonstrate that the coef…
Optimal Runge approximation for nonlocal wave equations and unique determination of polyhomogeneous nonlinearities
Yi-Hsuan Lin, Teemu Tyni, Philipp Zimmermann
The main purpose of this article is to establish the Runge-type approximation in for solutions of linear nonlocal wave equations. To achieve this, we…
Inverse scattering problems for non-linear wave equations on Lorentzian manifolds
Spyros Alexakis, Hiroshi Isozaki, Matti Lassas +1
We show that an inverse scattering problem for a semilinear wave equation can be solved on a manifold having an asymptotically Minkowskian infinity, that is, scattering functionals…