PIRSA:19060001

Video URL

https://pirsa.org/19060001

Simplifying general relativity

Liddle, A. (2019). Simplifying general relativity. Perimeter Institute for Theoretical Physics. https://pirsa.org/19060001

Liddle, Andrew. Simplifying general relativity. Perimeter Institute for Theoretical Physics, Jun. 11, 2019, https://pirsa.org/19060001 

          @misc{ scivideos_PIRSA:19060001,
            doi = {10.48660/19060001},
            url = {https://pirsa.org/19060001},
            author = {Liddle, Andrew},
            keywords = {Cosmology},
            language = {en},
            title = {Simplifying general relativity},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2019},
            month = {jun},
            note = {PIRSA:19060001 see, \url{https://scivideos.org/pirsa/19060001}}
          }

Andrew Liddle University of Lisbon

Talk numberPIRSA:19060001
DOI10.48660/19060001
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

Modified gravity theories typically feature numerous additional parameters and functions as compared to general relativity, which are unmotivated by observations and challenging to meaningfully constrain. We instead propose a new theory of gravity with the startling property of having *fewer* degrees of freedom than general relativity with a cosmological constant, by invoking a duality property within a first-order formulation that supports torsion. In this theory the cosmological constant becomes a space-time variable without introduction of kinetic terms, but its behaviour is tied to that of matter. I will describe the main properties of the theory, including its implications for cosmology. While there are strong indications that the simplest incarnation of the theory is not observationally viable, the theory can be used as a starting point for various extensions which appear more promising.

Based on arXiv:1905.10380 and arXiv:1905.10382, with Alexander, Cortês, Magueijo, Sims, and Smolin.