Increasing stability in an inverse problem for the acoustic equation

@inproceedings{Nagayasu2011IncreasingSI,
title={Increasing stability in an inverse problem for the acoustic equation},
author={Sei Nagayasu and Gunther Uhlmann and Jenn-Nan Wang},
year={2011}
}

In this work we study the inverse boundary value problem of determining the refractive index in the acoustic equation. It is known that this inverse problem is ill-posed. Nonetheless, we show that the ill-posedness decreases when we increase the frequency and the stability estimate changes from logarithmic type for low frequencies to a Lipschitz estimate for large frequencies.