I will present the idea that the big bang is a type of mirror -- in particular a "CPT mirror". I will review the evidence for this idea, its explanatory power, and its predictions. Recently, we have come to think this idea is closely tied to the asymptotic safety idea, and I will present a new result to this effect (in collaboration with Neil Turok and Vatsalya Vaibhav -- to appear soon).
The chiral Ising-, XY-, and Heisenberg models serve as effective descriptions of Dirac semimetals undergoing a quantum phase transition into a symmetry-broken ordered state. Interestingly, their quantum critical points govern the physical behavior of the system in the vicinity of the transition even at finite temperatures. In this contribution, we explore the chiral models at zero and finite...
We investigate $\beta$-functions of quantum gravity using dimensional regularisation. In contrast to minimal subtraction, a non-minimal renormalisation scheme is employed which is sensitive to power-law divergences from mass terms or dimensionful couplings. By construction, this setup respects global and gauge symmetries, including diffeomorphisms, and allows for systematic extensions to...
I will introduce the concept of restricted Weyl invariances and discuss their advantages for matter fields in curved space and their disadvantages for quantum gravity.
Strong first-order phase transitions (SFOPT) during the evolution of the Higgs potential in the early universe not only allow for the dynamical generation of the observed matter-antimatter asymmetry, they can also source a stochastic gravitational wave (GW) background possibly detectable with future space-based gravitational waves interferometers. As SFOPTs are phenomenologically incompatible...
