Jean Alexandre (KCL)
[TBA]
Fay Dowker (Imperial College London)
"To get to semiclassical gravity, we need to solve the cosmological constant problem"
I will argue that from a path integral perspective, the cosmological constant problem presents itself in a particular form. The gravitational path integral includes spacetimes that are nothing like the large smooth spacetimes of semiclassical gravity. There is evidence that these "unruly" spacetimes threaten to dominate the gravitational path integral due to the fact that there are so many of them compared to the large smooth spacetimes.
This is a struggle between Action and Entropy, if you will, and
I will explain why this is the path integral form of the cosmological constant problem. I will use causal set quantum gravity as an example of how (one aspect of) the cosmological constant problem might be solved in quantum gravity.
Ivette Fuentes (University of Southampton)
[TBA]
Steffen Gielen (University of Sheffield)
[TBA]
Atsushi Higutsi (University of York)
"Curious symmetries for free bosonic nonzero-spin fields in de Sitter spacetime"
Some symmetries for free bosonic nonzero-spin fields in four-dimensional de Sitter spacetime generated by conformal Killing vectors are presented. For the massless fields these and the Killing symmetries form an so(4,2) algebra. For the massive fields these symmetries do not seem to form a finite Lie algebra and appear to lead to infinitely many symmetries.
Patricia Ribes Metidieri (University of York)
[TBA]