Geometric Foundations of Gravity 2025

Session

Monday Parallel 4 - A101

30 Jun 2025, 15:40

A101 (University of Tartu, Physicum)

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

Antonio Racioppi (National Institute of Chemical Physics and Biophysics (EE))

30/06/2025, 15:40

Contributed talks

Talk

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...

36. On the geometric origin of the energy-momentum improvement terms

Damianos Iosifidis (University of Tartu, Scuola Superiore Meridionale)

30/06/2025, 16:05

Contributed talks

Talk

I will show how the Belinfante-Rosenfeld improvement terms, that render the energy-momentum tensor symmetric, emerge by coupling the matter to the affine-connection. In this sense the improvement terms correspond to the hypermomentum of matter. I will show how this is realized in two standard examples, the Maxwell field and the Dirac field. I will also show how the connection-matter couplings...

47. Friedmann cosmology with hyperfluids

Margus Saal (University of Tartu)

30/06/2025, 16:30

Contributed talks

Talk

In metric-affine gravity, both the gravitational and matter actions depend not just on the metric, but also on the independent affine connection. Thus, matter can be modeled as a hyperfluid, characterized by both the energy-momentum and hypermomentum tensors. The latter is defined as the variation of the matter action with respect to the connection, and it encodes extra (micro)properties of...

43. Internal gauge structure and ghost instabilities in general torsion theories

Dr Dario Sauro (Theoretical Physics Institute University ofJena)

30/06/2025, 16:55

Contributed talks

Talk

We analyze which internal affine gauge transformations can be attributed to the torsion, focussing on those that tensor give rise to Lie algebras. We find two such non-trivial structures, in which the gauge parameters are a two form and a scalar. In the first case gauge invariant variables are singled out, and a higher derivative power-counting renormalizable invariant action is derived. The...