Cosmology Seminar

Our next cosmology seminar takes place on Wednesday 1st of December, seminar room E349 at 2pm. The speaker is Maxence Corman from the Perimeter Institute (Waterloo, Canada).

At 14:00, room E349, Maxence Corman (PI), will be talking about

Evolving black holes in a nonsingular bouncing universe

One of the main unanswered questions of theoretical cosmology is whether the universe emerged from a big bang followed by a period of inflation or whether it had no beginning at all and bounced from a period of slow contraction to the current expanding phase. It has been shown recently that it is possible for the universe to undergo a nonsingular bounce at energies well below the Planck scale such that the entire evolution can be treated classically. It is however still unclear how to treat the passage of any pre-existing black holes through the bounce to the expanding phase. In this talk, we use numerical techniques to consider the classical evolution of a black hole in a non-singular universe driven by a ``ghost’’ scalar field. We find that at least for small enough black holes, the black hole passes through the bounce freely, albeit losing energy in the process. Pushing this further, we also show that if the Hubble patch during contraction shrinks to a size comparable or smaller than the radius of the black hole this gives rise to interesting dynamics such as disappearing and re-emerging horizons.