Geometric Foundations of Gravity 2025

Session

Tuesday Parallel 4 - A101

1 Jul 2025, 15:40

A101 (University of Tartu, Physicum)

20. Geometry of Disformal Transformations

Jordi Gaset Rifà (CUNEF Universidad)

01/07/2025, 15:40

Contributed talks

Talk

Disformal transformations are specific deformations of the metric, involving other fields and their derivatives. They have been used to relate different modified gravity models. For instance, mimetic and teleparallel gravities.

We will put forward a geometric formulation of disformal transformations, thereby elucidating the role of the non-metric fields therein. We will also identify key...

40. Chiral signatures from the Barbero–Immirzi parameter in inflationary tensor modes

Mehraveh Nikjoo

01/07/2025, 16:05

Contributed talks

Talk

The Ashtekar connection-based approach of general relativity offers a compelling avenue for re-examining gravitational dynamics, particularly through its Hamiltonian formulation. This framework introduces the Barbero–Immirzi parameter, a factor whose role varies between classical and quantum treatments.

Classically, the Barbero–Immirzi parameter does not appear in the equations describing...

29. On the quantum equivalence between Teleparallel Gravity and GR

Davide Zarrilli

01/07/2025, 16:30

Contributed talks

Talk

In this talk I will show our recent work on the quantization of Teleparallel Gravity (or TEGR), which is classically equivalent to GR. I compute the quadratically divergent counterterms that arise in the action, showing that they break the equivalence with GR at the quantum level. I then compute the logarithmically divergent counterterms and discuss their implications.

33. Causality and Stability from the Acoustic Metric

Ignacy Sawicki (CEICO, Institute of Physis, Czech Academy of Sciences)

01/07/2025, 16:55

Contributed talks

Talk

Scalar-tensor theories with derivative interactions form backgrounds which spontaneously break Lorentz invariance (cosmology during inflation or the dark energy era is the archetype). I will discuss how to think about the dynamics of free scalar perturbations, phonons, on general anisotropic backgrounds, showing that phonons move on null geodesics of an acoustic spacetime described by its own...