Description
chair: Anna Nakonieczna, Piotr Sułkowski
Gravitational physics is arguably better understood in the presence of a negative cosmological constant than a positive one, yet there exist strong technical similarities between the two settings. These similarities can be exploited to enhance our understanding of the more speculative realm of quantum cosmology, building on robust results regarding anti-de Sitter black holes describing the...
I will present how pre-main sequence and low-mass stars' (M<0.5 solar mass) can be a laboratory for constraining theories of gravity. We will discuss modified gravity impacts on their early evolution, such as Hayashi tracks and radiative core development, together with the measured quantities such as effective temperature, masses, and luminosities as well as fusion of light elements.
I will discuss the AdS/CFT correspondence with finite cut-off and TT-deformations of holographic conformal field theories. After introduction, I will present some recent results for the deformations of 2d conformal field theories on curved backgrounds and their holographic realization in Anti-de Sitter geometries in 3 spacetime dimensions.
Cyclic universes with bouncing solutions are candidates for solving the big bang initial singularity problem. Here I will look for bouncing solutions in the context of modified Gauss-Bonnet gravity theories whose field equations contain up to fourth-order derivatives of the metric tensor. In finding such bouncing solutions I will resort to an order reduction technique that reduces the order of...
We consider a recent proposal to obtain a finite contribution of second derivative order to the gravitational field equations in $D = 4$ dimensions from a renormalized Gauss-Bonnet term in the action. In previous works, it has been shown that the resulting field equations cannot be obtained as the Euler-Lagrange equations from a diffeomorphism-invariant action. Here we use techniques from the...
In this talk, I summarize the process of investigating neutrino oscillations within the framework of extended theories of gravity. Based on the covariant reformulation of Pontecorvo’s formalism, the oscillation probability of neutrinos propagating in static spacetimes described by gravitational actions quadratic in the curvature invariants is evaluated. For the sake of simplicity, calculations...
Horndeski gravity is the most general scalar tensor theory, with a single scalar field, leading to second-order field equations and after the GW170817 it has been severely constrained. In this talk, I will present an analog of Horndeski’s theory in the Teleparallel Gravity framework where gravity is mediated through torsion instead of curvature. It will be shown that, even though, many terms...
