Phase transitions in three dimensions, described by the Wilson-Fisher fixed point, play a pivotal role in condensed matter physics and may also have significant implications
for the physics of the Early Universe. In this context, using the most general theory coupling scalar fields non-minimally to Einstein gravity and exploiting the proper-time functional renormalization group equation, we...
The formalism of Open Quantum Systems with linearised gravity as environment serves as a tool to predict the effective evolution of quantised matter systems under the influence of gravity. It is of use to analyse features of specific quantum gravity candidate theories and to search for signs of quantum gravity effects for instance in neutrino oscillations.
In the talk, a model consisting of...
In the string axiverse scenario, primordial black holes (PBHs) can sustain non-negligible spin parameters as they evaporate. We show that tracking both the mass and spin evolution of a PBH in its final hour can yield a purely gravitational probe of new physics beyond the TeV scale, allowing one to determine the number of new scalars, fermions, vector bosons, and spin-3/2 particles....
We compute the physical running of a general higher derivative scalar coupled to a nondynamical metric and of higher derivative Weyl-invariant gravity with a dynamical metric in four dimensions. The physical running differs from the μ-running of dimensional regularization due to infrared divergences, unlike in standard two-derivative theories. Using the higher derivative scalar as a toy model,...
Renormalization Group flow in Quantum Einstein Gravity shows gauge and parametrization dependence in quantities such as beta functions and generating functionals.
Using a proper-time regulated flow equation for a Wilsonian effective action, we investigate the properties of the non-Gaussian fixed point in both the Background Field gauge and the Physical gauges, employing linear and exponential...
I will review the Hubble tension and its current status, before discussing five brief recent lessons which can be summarized as follows: 1) pre-recombination new physics alone is not sufficient to solve the tension; 2) constructing a successful model of pre-plus-post-recombination new physics is difficult; 3) Omega_m and omega_c play a key role in the discussion; 4) local structure can make...
Currently, the study of cosmological correlation functions is extremely favored, and a large number of new techniques are being developed. I will discuss a less fashionable but efficient technique to calculate the loop corrections to a correlation function in the long-wavelength approximation: through the use of the Yang-Feldman-type equation. I will also discuss the obtained results'...
