Application deadline : April 30, 2021
Starting date : between July 2021 and January 2022, upon mutual agreement
Description of the position :
Black holes quasinormal modes (QNM) or resonances are a fundamental notion playing a key role in the detection of gravitational waves in the LIGO and VIRGO projects. Using a recently proposed hyperboloidal foliation approach
due to Warnick, QNM can be viewed as mere eigenvalues of non-selfadjoint Schrödingerlike operators depending on the geometry of the black holes and on the particular hyperboloidal foliation. Numerical results due to Jaramillo et al. indicate that QNM are unstable under small perturbations. Moreover, this instability phenomenon is confirmed by the numerical analysis of the pseudo-spectrum. The research project of this postdoc will consist in understanding both theoretically and numerically this observation and its universality (that is whether it depends on the geometry and/or the chosen hyperboloidal foliation). The foreseen research directions would be :
- analysing the inverse resonances problem, that is the problem of determining the
geometry of the black hole from the knowledge of its QNM, - providing a certified numerical scheme to compute the first QNM and overtones.