Gravitational quasinormal modes of black holes in Einstein-aether theory

The local Lorentz violation (LV) in gravity sector should show itself in derivation of the characteristic quasinormal modes (QNMs) of black hole mergers from their general relativity case. In this paper, I study QNMs of the gravitational field perturbations to Einstein-aether black holes and, at first compare them to those in Schwarzschild black hole, and then some other known LV gravity theories. By comparing to Schwarzschild black hole, the first kind aether black holes have larger damping rate and the second ones have lower damping rate. And they all have smaller real oscillation frequency of QNMs. By comparing to some other LV theories, the QNMs of the first kind aether black hole are similar to that of the QED-extension limit of standard model extension, non-minimal coupling to Einstein's tensor and massive gravity theories. While as to the second kind aether black hole, they are similar to those of the noncommutative gravity theories and Einstein-Born-Infeld theories. These similarities may imply that LV in gravity sector and LV in matter sector have some intrinsic connections.Comment: 14 pages,8 figures, accepted by Nucl. Phys. B. arXiv admin note: substantial text overlap with arXiv:1707.0674

Particle energy and Hawking temperature

Some authors have recently found that the tunneling approach gives a different Hawking temperature for a Schwarzschild black hole in a different coordinate system. In this paper, we find that to work out the Hawking temperature in a different coordinate system by the tunneling approach, we must use the correct definition of the energy of the radiating particles. By using a new definition of the particle energy, we obtain the correct Hawking temperature for a Schwarzschild black hole in two dynamic coordinate systems, the Kruskal-Szekers and dynamic Lemaitre coordinate systems.Comment: 11 pages; Accepted by PL