Speaker
Description
The de Sitter spacetime, first found by Willem de Sitter in 1917, is a solution to the Einstein field equations without matter and with a positive cosmological constant. Current observations suggest that our universe has a small positive cosmological constant, Λ, and that it is asymptotically de Sitter, demonstrating the important role of positive Λ solutions and in particular of the de Sitter solution in modern cosmology.
In addition to the "pure" de Sitter solution, other solutions with Λ > 0 exist. One example is the Schwarzschild-de Sitter solution which represents an asymptotically de Sitter spacetime with a central black/white hole. Considering the connection between event horizons and temperature, which was first understood for BH event horizons and then generalized to cosmological event horizons, this spacetime is characterized by two temperatures: the BH Hawking temperature and the cosmological de Sitter temperature. The two temperatures, which are associated with a stationary state, are different and therefore thermal equilibrium in Schwarzschild-de Sitter spacetime is, in general, unreachable, making a consistent thermodynamical formulation impossible. Nevertheless, there are cases where this formulation is possible and their study is mandatory for a better understanding of the interaction between black holes, cosmological horizons, and matter.
In this talk, I am going to summarize the analyzis of the de Sitter and Schwarzschild-de Sitter solutions. Furthermore, I will briefly comment on the final objective of my master’s thesis which is to formulate a consistent thermodynamical framework in a Schwarzschild-de Sitter spacetime through the addition of hot matter has a link between the two different temperatures originating from the existing two types of event horizons.
