in this scenario exhibits quasibound states at complex wavenumber $k=k_{\mathrm{r}}-i\,\kappa$; here $\kappa$ measures the escape rate which is related to the quality factor via $$Q=\frac{k}{2\kappa}.\label{eq:QfactorDef}$$ WGMs in oval resonators are special states that preserve long lifetimes comparable to those found in circular dielectrics [@ISI:000320621600008], due to the fact that they are predominantly localized in the phase-space region corresponding to total internal reflection at the dielectric boundary. When the invariant curves (tori) that foliate this phase-space region in the limit of circular symmetry are gradually broken up following the KAM theorem as applied to convex billiards [@LazutkinBook], regular WGMs become *chaotic* WGMs in which rays explore regions of phase space in which the rays cease to be confined by total internal reflection. The critical angle for total internal reflection defines an escape window in phase space rather than real space, because this angle is directly related to the tangential momentum component at the surface of the resonator. In Ref.  [@Nockel:1997lr], an approximate semiclassical quantization of these unconventional modes was proposed based on a separation of time scales between the fast whispering-gallery circulation and a slower spiraling-in toward the escape window, making it possible to identify *adiabatic invariant curves.* Their location then 