Geometric Foundations of Gravity 2025

Session

Monday Parallel 2 - A101

30 Jun 2025, 13:30

A101 (University of Tartu, Physicum)

19. Quintessential inflation in Palatini F(R,X) gravity

Christian Dioguardi (NICBP)

30/06/2025, 13:30

Contributed talks

Talk

Palatini $F(R,X)$ gravity, with $X$ the inflaton kinetic term, proved to be a powerful framework for generating asymptotically flat inflaton potentials. Here we show that a quadratic Palatini $F(R,X)$ restores compatibility with data of the Peebles-Vilenkin quintessential model. Moreover, the same can be achieved with an exponential version of the Peebles-Vilenkin potential if embedded in a...

53. The formulation interpolation: the quasi-Palatini approach to modified gravity

Sotirios Karamitsos (University of Tartu)

30/06/2025, 13:55

Contributed talks

Talk

Distinct formulations of nonminimal models have been a leading motivating factor for the development of alternative theories of gravity. The metric and Palatini formulations, understood to be equivalent in minimally coupled models, can lead to physically distinct theories when a nonminimal coupling is introduced. The choice of formulation, made before the action is written down, is a discrete...

39. Global Portraits of Inflation in Nonsingular Variables

Dmitri Kraiko (University of Tartu)

30/06/2025, 14:20

Contributed talks

Talk

In the phase space perspective, scalar field slow roll inflation is described by a heteroclinic orbit from a saddle type fixed point to a final attractive point. In many models the saddle point resides in the scalar field asymptotics, and thus for a comprehensive view of the dynamics a global phase portrait is necessary. For this task, in the literature one mostly encounters dynamical...

49. Testing non - metricity based gravity models against cosmological data.

Purnendu Karmakar (University of Tartu)

30/06/2025, 14:40

Contributed talks

Talk

We investigate non-metricity-based gravity models through a model-independent framework, confronting them with recent observational data. Employing Bayesian statistical methods, we analyze late time background evolution using DESI-BAO and Supernovae data, and probe linear perturbations via the modified gravity functions, effective gravitational coupling and damping in the gravitational wave...