The analysis of quantum states in non-smooth spacetimes has two main motivations. First, there are several models of physical phenomena that require spacetime metrics with finite regularity. These include models of gravitational collapse, astrophysical objects and general relativistic fluids. Second, the well-posedness of Einstein’s equations, viewed as a system of hyperbolic PDE requires...
Making use of the 1 + 3 covariant formalism, we show explicitly the effect that nonmetricity has on the dynamics of the universe. Then, using the Dynamical System Approach, we analyze the evolution of Bianchi type-I cosmologies within the framework of f(Q) gravity. We consider several models of function f(Q), each of them manifesting isotropic eras of the universe, whether transitional or not....
I discuss recent developments in the analysis of the conformal backreaction exerted by conformal matter on the external classical gravitational metric. The approach relies on a reconstruction of the effective action exploiting conformal symmetry in momentum space.
Conformal symmetry imposes strong constraints on correlation functions. Indeed, the general structure of 2 and 3-point functions is completely fixed up to a few constants by such symmetry. These results are usually obtained in position space in contrast with general QFT where Feynman diagrams are typically computed in momentum space. I will discuss how conformal symmetry completely determines...
