Pseudospectrum of rotating analog black holes

Abstract: Analyzing the stability of quasinormal modes (QNM) is essential for understanding black hole dynamics, particularly in the context of gravitational wave emissions and black hole spectroscopy. In this study, we employ the hyperboloidal approach to reformulate the quasinormal mode problem of a rotating analog black hole, effectively transforming it into an eigenvalue problem associated with a nonself-adjoint operator. Using this method, we examine the influence of rotation on the stability of the QNM spectrum, relying on the associated pseudospectrum for qualitative assessment. Our findings indicate that the prograde overtones become more stable as rotation increases. This work enhances our understanding of spectrum stability in rotating systems and expands the study of pseudospectra in non-spherically symmetric spacetimes, with potential for empirical testing in terrestrial laboratories.