We review properties of solutions in bigravity theory for a specific case where two metric tensors, gμν and fμν , satisfy proportional relation fμν = Cgμν . For this condition, we find that the solutions describing the asymptotically de Sitter space-time can be obtained and investigate the perturbation around the Schwarzschild–de Sitter solutions and corresponding anti-evaporation. We discuss t...

We consider a model with two parallel (positive tension) 3-branes separated by a distance L in five-dimensional spacetime. If the interbrane space is anti--de Sitter, or is not precisely anti--de Sitter but contains no event horizons, the effective four-dimensional cosmological constant seen by observers on one of the branes (chosen to be the visible brane) becomes exponentially small as L grow...

We study the semiclassical evolution of a self-gravitating thick shell in Anti-de Sitter space-time. We treat the matter on the shell as made of quantized bosons and evaluate the back-reaction of the loss of gravitational energy which is radiated away as a non-adiabatic effect. A peculiar feature of anti-de Sitter is that such an emission also occurs for large shell radius, contrary to the asym...

We define the local acceleration and jerk of a relativistic brane in an ambient spacetime, and construct from them a dimensionless parameter λ that must be small for an interpretation of brane acceleration as local Unruh temperature. As examples, we discuss (i) open rotating branes, for which λ > 1 (ii) closed spherical branes expanding in Minkowski spacetime, for which λ = 0 when the worldvolu...

We investigate representations of the conformal group that describe “massless” particles in the interior and at the boundary of anti-de Sitter space. It turns out that massless gauge excitations in anti-de Sitter are gauge “current” operators at the boundary. Conversely, massless excitations at the boundary are topological singletons in the interior. These representations lie at the threshold o...

We obtain a class of exact solutions representing null particles moving in three-dimensional (anti-) de Sitter spaces by boosting the corresponding static point source solutions given by Deser and Jackiw. In de Sitter space the resulting solution describes two null particles moving on the (circular) cosmological horizon, while in anti-de Sitter space it describes a single null particle propagat...