Approximate cloaking for the full wave equation via change of variables (Q2902743)

In the considered approximate cloaking scheme one uses two layers. The one is inspired from the standard scheme, introduced in [\textit{R. V. Kohn}, et al., Inverse Probl. 24, No. 1, Article ID 015016, 21 p. (2008; Zbl 1153.35406)]. The next one is an appropriate lossy layer similar to the one considered by \textit{R. V. Kohn} et al. [Commun. Pure Appl. Math. 63, No. 8, 973--1016 (2010; Zbl 1194.35505); erratum ibid. 63, No. 11, 1525--1531 (2010; Zbl 1221.35449)]. The degree of approximate cloaking is estimated in two and three dimensions. To obtain the degree of non-invisibility estimates for the wave equation, one transforms, by means of Fourier transform with respect to time, the wave equation into a family of Helmholtz equations, establishes the appropriate degree of near-invisibility estimates for these Helmholtz equations and then invert the Fourier transform.