Sep 22 – 25, 2025
University of Warsaw, Faculty of Physics
Europe/Warsaw timezone

$\tilde\xi$-attractors in metric-affine gravity

Sep 22, 2025, 11:00 AM
30m
0.06 (University of Warsaw, Faculty of Physics)

0.06

University of Warsaw, Faculty of Physics

Pasteura 5, 02-093 Warsaw, Poland
Plenary Plenary 2

Speaker

Antonio Racioppi (NICPB, Tallinn, Estonia)

Description

We propose a new class of inflationary attractors in metric-affine gravity. Such class features a non-minimal coupling $\tilde\xi \, \Omega(\phi)$ with the Holst invariant $\tilde {\cal R}$ and an inflaton potential proportional to $\Omega(\phi)^2$. The attractor behaviour of the class takes place with two combined strong coupling limits. The first limit is realized at large $\tilde\xi$, which makes the theory equivalent to a $\tilde {\cal R}^2$ model. Then, the second limit considers a very small Barbero-Immirzi parameter which leads the inflationary predictions of the $\tilde {\cal R}^2$ model towards the ones of Starobinsky inflation. Because of the analogy with the renown $\xi$-attractors, we label this new class as $\tilde\xi$-attractors.

Primary author

Antonio Racioppi (NICPB, Tallinn, Estonia)

Presentation materials