We derive an expression for functional determinants in thermal spacetimes as a product over the corresponding quasinormal modes. As simple applications we give efficient computations of scalar determinants in thermal AdS, BTZ black hole and de Sitter spacetimes. We emphasize the conceptual utility of our formula for discussing ‘1/N ’ corrections to strongly coupled field theories via the hologr...

We study the determination of mass a de Sitter-Schwarzschild black hole from one quasinormal mode. prove local uniqueness result with H\"older type stability estimate.

We construct the covariantly defined multipole moments on common horizon of an equal-mass, non-spinning, quasicircular binary-black-hole system. see a strong correlation between these and gravitational waveform. find that are well described by fundamental quasinormal modes at sufficiently late times. For each moment, least two different $\ell$ detectable in best model. These models provide fait...