Polarization map of the CMB + galactic foregrounds at 140 GHz
Credit: Susanna Azzoni (Oxford)

Cosmology seminar: Large scale geometry of the Universe

21 Feb 2023
Seminars and colloquia
Time
Venue
Beecroft Seminar Room
Denys Wilkinson Building, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH
Speaker(s)

Tomislav Prokopec (Utrecht University)

Seminar series
Cosmology
Knowledge of physics?
Yes, knowledge of physics required

Abstract:

In this lecture I will discuss the question of a general interest, namely what is the large scale geometry of the Universe. Our conjecture put forward in e-Print: 2211.16893 [astro-ph.CO] is:

The large scale geometry of the Universe is one of the eight Thurston geometries (or a combination of Thurston geometries smoothly sewn together).

Next I will show that the anisotropy problem present in some of the Thurston geometries can be solved in analogous way as the flatness problem of standard FLRW geometries. In the remainder of the talk, I will discuss methods how to test our hypothesis. The simplest test is parity, as three of the Thurston geometries -- namely U(H(2)), Nil and Solv -- violate parity. More comprehensive tests involve measurements of luminosity distance and angular diameter distance of different objects in the LSS and CMB fluctuations. We leave detailed forecasting implementations of these tests to a future investigation.