19 citations · 74 across the 17 of their papers we have counts for
17 papers
Gravitational ultra-relativistic freeze-out during general reheating
Mathieu Gross, Stephen E. Henrich, Fotis Koutroulis
We investigate ultrarelativistic freeze-out (UFO) in the context of generic reheating scenarios. While the standard WIMP dark matter paradigm has been extensively studied, UFO has…
UV-complete and stable Quintom Dark Energy models in the light of DESI DR2
Fotis Koutroulis
We propose that Quintom dark energy, the simplest framework allowing crossing of the cosmological-constant boundary, admits a natural UV completion in a 5D anisotropic orbifold lat…
Quark, lepton and right-handed neutrino production via inflation
Duarte Feiteira, Fotis Koutroulis, Oleg Lebedev +1
Inflationary expansion of space-time provides us with an efficient particle production mechanism in the Early Universe. The fermion production efficiency depends critically on the…
The thermal backreaction of a scalar field in de Sitter spacetime
Nikos Irges, Antonis Kalogirou, Fotis Koutroulis
We argue that a scalar field in de Sitter spacetime should feel explicit thermal effects associated with its curvature. Starting from the Bunch-Davies vacuum and a scalar field wit…
Dark Branes for Dark Matter
Fotis Koutroulis, Eugenio Megias, Stefan Pokorski +1
We propose a setup for the origin of dark matter based on spacetime with a warped extra dimension and three branes: the Planck brane, the TeV brane, at a (few) TeV scale , and…
Gravitational production of sterile neutrinos
Fotis Koutroulis, Oleg Lebedev, Stefan Pokorski
We consider gravitational production of singlet fermions such as sterile neutrinos during and after inflation. The production efficiency due to classical gravity is suppressed by t…
Machine Learning Classification of Sphalerons and Black Holes at the LHC
Aurora Singstad Grefsrud, Trygve Buanes, Fotis Koutroulis +6
In models with large extra dimensions, "miniature" black holes (BHs) might be produced in high-energy proton-proton collisions at the Large Hadron Collider (LHC). In the semi-class…
Phases of Pseudo-Nambu-Goldstone Bosons
Fotis Koutroulis, Matthew McCullough, Marco Merchand +2
We study the vacuum dynamics of pseudo-Nambu-Goldstone bosons (pNGBs) for spontaneous and explicit symmetry breaking. We determine the magnitude of expl…
Flavour and Higgs physics in -symmetric 2HD models near the decoupling limit
Arturo de Giorgi, Fotis Koutroulis, Luca Merlo +1
With no evidence of any exotic particle detected so far beyond the Standard Model, the new physics may lie above the presently accessible energies at colliders and, at low-energies…
Ising Cosmology
Nikos Irges, Antonis Kalogirou, Fotis Koutroulis
Using arguments from holography we propose that the deviation of the cosmological spectral index of scalar fluctuations from unity may be controlled almost entirely by the cr…
Thermal effects in Ising Cosmology
Nikos Irges, Antonis Kalogirou, Fotis Koutroulis
We consider a real scalar field in de Sitter background and compute its thermal propagators. We propose that in a dS/CFT context, non-trivial thermal effects as seen by an 'out' ob…
RG flows in Non-Perturbative Gauge-Higgs Unification II. Effective action for the Higgs phase near the quantum phase transition
Nikos Irges, Fotis Koutroulis
We construct the zero temperature (no compact dimensions) effective action for an SU(2) Yang-Mills theory in five dimensions, with boundary conditions that reduce the symmetry on t…
The conformal N-point scalar correlator in coordinate space
Nikos Irges, Fotis Koutroulis, Dimosthenis Theofilopoulos
We present a systematic derivation of the form of correlators of N operators in a Conformal Field Theory in d>2 dimensions and the exchange-symmetry constraints that the functions…
On RG flows in Generalized Effective Field Theory
Nikos Irges, Fotis Koutroulis
Generalized Effective Field Theory (GEFT) is the non-renormalizable extension of an Effective Field Theory where the Wilson coefficients are endowed by their own, independent scale…
Symmetry breaking and RG flows with higher dimensional operators
Nikos Irges, Fotis Koutroulis
We discuss the role of higher dimensional operators in the spontaneous breaking of internal symmetry and scale invariance, in the context of the Lorentz invariant scalar field theo…
RG flows in Non-Perturbative Gauge-Higgs Unification I
Nikos Irges, Fotis Koutroulis
We initiate the continuum description of a non-perturbative 5d lattice Yang-Mills model with 4d boundaries using the -expansion. In its simplest version classically th…
Renormalization of the Abelian-Higgs Model in the R-xi and Unitary gauges and the physicality of its scalar potential
Nikos Irges, Fotis Koutroulis
We perform an old school, one-loop renormalization of the Abelian-Higgs model in the Unitary and gauges, focused on the scalar potential and the gauge boson mass. Our goal is…