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arXiv · 2305.14412

Cavity effect in the quasinormal mode spectrum of topological stars

Pierre Heidmann·Nicholas Speeney·Emanuele Berti·Ibrahima Bah
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Abstract

We study scalar perturbations of topological solitons, smooth horizonless solutions in five-dimensional Einstein-Maxwell theory that correspond to coherent states of gravity via the dynamics of extra compact dimensions. First, we compute scalar quasinormal modes for topological stars that have a single unstable photon sphere, and we show that the spectrum is very similar to that of a black hole with the same photon sphere. Next, we study topological stars that have both a stable inner photon sphere and an unstable one. The first few quasinormal modes are localized around the inner photon sphere. The spectrum also contains ''black-hole like modes'' localized at the unstable outer photon sphere. The frequencies of these modes are similar to those of a black hole, but their imaginary part is smaller due to a cavity effect associated with the inner photon sphere. The longer damping produced by this trapping effect may have implications for black hole spectroscopy.

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Pierre Heidmann, Nicholas Speeney, Emanuele Berti, Ibrahima Bah. 2023-05-23. Cavity effect in the quasinormal mode spectrum of topological stars. https://doi.org/10.1103/physrevd.108.024021

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