12 papers
Differential Obstructions to Curvature-Dependent Conformal Transformations
David S. Pereira, Francisco S. N. Lobo, José Pedro Mimoso
Curvature-dependent conformal rules are local forward assignments on known metrics, but they are not generically local changes of metric variables. We study the nondegenerate class…
Big Bang Nucleosynthesis constraints on gravity
Daniel F. P. Cruz, David S. Pereira, Francisco S. N. Lobo +1
We investigate Big Bang Nucleosynthesis (BBN) in the framework of gravity, where the gravitational Lagrangian depends on the torsion scalar and the matter Lagrangian…
On the robustness of the angular homogeneity scale : a comparative analysis of computational approaches
Pedro Fanha, António da Silva, José Fonseca +2
The assumption of large-scale homogeneity is a cornerstone of modern cosmology and underlies the validity of the FLRW framework. Testing the scale at which the Universe transitions…
Gravitational baryogenesis beyond the spectator approximation
David S. Pereira, Beatriz A. Fernandes, José Pedro Mimoso
The standard gravitational-baryogenesis operator , with , is usually treated as a spectator interaction that generates an effective ch…
Eckart heat-flux applicability in theories and the existence of temperature gradients
David S. Pereira, José Pedro Mimoso
We show that in single--scalar theories of the form , a generic nonminimal coupling induces, in the scalar--comoving frame, an additional tr…
Thermal channels of scalar and tensor waves in Jordan-frame scalar--tensor gravity
David S. Pereira, Francisco S. N Lobo, José Pedro Mimoso
We study first-order scalar and tensor perturbations of Jordan-frame scalar--tensor gravity about a spatially flat FLRW background using the Einstein-like effective-fluid decomposi…