123 citations · 659 across the 33 of their papers we have counts for
8 papers · 1 filter
A scaling non-compact QCD axion
Georgios K. Karananas, Mikhail Shaposhnikov
We present a dynamical mechanism for the erasure of inflationary isocurvature perturbations of the non-compact QCD axion. The key ingredient is an early-time runaway exponential po…
A non-compact QCD axion
Georgios K. Karananas, Mikhail Shaposhnikov, Sebastian Zell
We investigate the cosmology of an axion that is fundamentally non-compact. During inflation, fluctuations of the effectively massless field populate many QCD vacua, thereby evadin…
Higgs inflation in Weyl-invariant Einstein-Cartan gravity
Georgios K. Karananas, Mikhail Shaposhnikov
In this short note we analyze the inflationary dynamics in Weyl-invariant Einstein-Cartan gravity coupled to the Standard Model of particle physics. We take the axion-like particle…
Field redefinitions, perturbative unitarity and Higgs inflation
Georgios K. Karananas, Mikhail Shaposhnikov, Sebastian Zell
For inflation driven by the Higgs field coupled non-minimally to gravity, we study the cutoff energy scale above which perturbation theory breaks down. Employing the metric formula…
Small-scale structure from neutron dark decay
Georgios K. Karananas, Alexis Kassiteridis
It was recently proposed that the disagreement in the experimental measurements of the lifetime of the neutron might be eradicated if the neutron decays to particles responsible fo…
Gauge coupling unification without leptoquarks
Georgios K. Karananas, Mikhail Shaposhnikov
We propose an interpretation of the gauge coupling unification scale which is not related to any new particle threshold. We revisit Grand Unified Theories and show that it is possi…
On the geometrical interpretation of scale-invariant models of inflation
Georgios K. Karananas, Javier Rubio
We study the geometrical properties of scale-invariant two-field models of inflation. In particular, we show that when the field-derivative space in the Einstein frame is maximally…
Higgs-Dilaton Cosmology: an effective field theory approach
Fedor Bezrukov, Georgios K. Karananas, Javier Rubio +1
The Higgs-Dilaton cosmological model is able to describe simultaneously an inflationary expansion in the early Universe and a dark energy dominated stage responsible for the presen…