We calculate the exact values of the quasinormal frequencies for an electromagnetic field and a gravitational perturbation moving in D-dimensional de Sitter spacetime (D ≥ 4). We also study the quasinormal modes of a real massive scalar field and we compare our results with those of other references.

We have studied scalar perturbations as well as fermion perturbations in pure de Sitter space-times. For scalar perturbations we have shown that well-defined quasinormal modes in d-dimensions can exist provided that the mass of scalar field m > d−1 2l . The quasinormal modes of fermion perturbations in three and four dimensional cases have also been investigated. We found that different from ot...

We calculate the scalar quasinormal modes of warped AdS3 black holes analytically. We find that in general they are not in agreement with the prediction of the usual AdS/CFT correspondence. Nevertheless, for the black hole not deviating far from BTZ black hole, the quasinormal frequencies are still well consistent with AdS/CFT correspondence. ∗Email:bchen01,[email protected]

The asymptotic quasinormal frequencies of the brane-localized (4 + n)dimensional black hole are computed. Since the induced metric on the brane is not an exact vacuum solution of the Einstein equation defined on the brane, the real parts of the quasinormal frequencies ω do not approach to the wellknown value TH ln 3 but approach to TH ln kn, where kn is a number dependent on the extra dimension...

We introduce two natural notions of Aluthge transforms (toral and spherical) for 2-variable weighted shifts and study their basic properties. Next, we study the class of spherically quasinormal 2-variable weighted shifts, which are the fixed points for the spherical Aluthge transform. Finally, we briefly discuss the relation between spherically quasinormal and spherically isometric 2-variable w...

We investigate the evolution of a scalar field propagating in Reissner-Nordström Anti-de Sitter spacetime. Due to the characteristic of spacetime geometry, the radiative tails associated with a massless scalar field propagation have an oscillatory exponential decay. The object-picture of the quasinormal ringing has also been obtained. For small charges, the approach to thermal equilibrium is fa...

The d-dimensional string generated gravity models lead to Einstein-Maxwell equations with quadratic order correction term called the Gauss-Bonnet term. We calculate the quasinormal modes for the d-dimensional charged black hole in the framework of this model. The quasinormal spectrum essentially depends upon the Gauss-Bonnet coupling parameter α which is related to the string scale, and is tota...

We study the wave equation for a massive scalar field in three-dimensional AdS (anti de Sitter) and dS (de Sitter) spaces to find what is the difference and similarity between two spaces. Here the AdS space is provided by the BTZ black hole with J = 0. To investigate its event (cosmological) horizons, we compute the absorption cross section, quasinormal modes, and study the AdS(dS)/CFT correspo...

We study the decay of charged scalar and spinor fields around Reissner-Nordström black holes in de Sitter spacetime through calculations of quasinormal frequencies of the fields. The influence of the parameters of the black hole (charge, mass), of the decaying fields (charge, spin), and of the spacetime (cosmological constant) on the decay is analyzed. The analytic formula for calculation quasi...

quasinormal subgroups have been studied for nearly 80 years. in finite groups, questions concerning them invariably reduce to p-groups, and here they have the added interest of being invariant under projectivities, unlike normal subgroups. however, it has been shown recently that certain groups, constructed by berger and gross in 1982, of an important universal nature with regard to the existen...