## Video URL

http://pirsa.org/18110064# Natural dynamics of the cosmological constant

### APA

Smolin, L. (2018). Natural dynamics of the cosmological constant. Perimeter Institute for Theoretical Physics. http://pirsa.org/18110064

### MLA

Smolin, Lee. Natural dynamics of the cosmological constant. Perimeter Institute for Theoretical Physics, Nov. 15, 2018, http://pirsa.org/18110064

### BibTex

@misc{ scivideos_PIRSA:18110064, doi = {}, url = {http://pirsa.org/18110064}, author = {Smolin, Lee}, keywords = {Quantum Gravity}, language = {en}, title = {Natural dynamics of the cosmological constant}, publisher = {Perimeter Institute for Theoretical Physics}, year = {2018}, month = {nov}, note = {PIRSA:18110064 see, \url{https://scivideos.org/index.php/PIRSA/18110064}} }

Lee Smolin Perimeter Institute for Theoretical Physics

## Abstract

We consider a natural extension of general relativity, by the addition of a term which is a topological invariant when the cosmological constant is in fact constant. Allowing the cosmological constant to vary, we discover it is endowed with a natural dynamics, which also includes a mechanism to suppress its value. A key role in hiding the consequences of a dynamical cosmological constant is played by the torsion of the spacetime connection.

As a dynamical variable, the varying cosmological constant turns out to be canonically conjugate to a measure of intrinsic, cosmological time, given by the Chern-Simons invariant of the Ashtekar connection (which we originally studied with Chopin Soo). As a result, a small quantum universe that "knows what time it is" does not know the value of the cosmological constant, and visa versa. This leads to some novel scenarios for the early universe.

This is joint work in progress with Stephon Alexander, Joao Magueijo and Robert Sims.