Zobrazeno 1 - 10
of 703
pro vyhledávání: '"Oikonomou, V. K"'
Autor:
Oikonomou, V. K
What if the dark matter Sector is truly dark, self-interacting and unreachable by terrestrial experiments? How could we find hints of such dark sector if it is experimentally unreachable by any terrestrial experiment? We study a low-scale mirror Stan
Externí odkaz:
http://arxiv.org/abs/2409.16095
Autor:
Oikonomou, V. K.
In this work we investigate the phenomenological implications of several non-trivial axion-Higgs couplings, which cover most of the possible non-perturbative scenarios. Specifically we consider the combination of having higher order non-renormalizabl
Externí odkaz:
http://arxiv.org/abs/2409.10709
Autor:
Oikonomou, V. K.
In this work we study the inflationary framework of Einstein-Gauss-Bonnet theories which produce a primordial gravitational wave speed that respects the constraint imposed by the GW170817 event, namely $\left| c_T^2 - 1 \right| < 6 \times 10^{-15}$ i
Externí odkaz:
http://arxiv.org/abs/2407.12155
Autor:
Odintsov, S. D., Oikonomou, V. K.
In this work we highlight an important perspective for the complete understanding of the stochastic gravitational background structure. The stochastic gravitational wave background is perhaps the most important current and future tool towards pinpoin
Externí odkaz:
http://arxiv.org/abs/2407.00491
Autor:
Oikonomou, V. K.
We consider the implications of a scalar field interacting with the dark matter fluid on the energy spectrum of the primordial gravitational waves. We choose an interaction type which before a critical matter density $\rho_m^c$ during the reheating e
Externí odkaz:
http://arxiv.org/abs/2406.09604
Autor:
Oikonomou, V. K.
In this work we consider an axionic scalar-tensor theory of gravity and its effects on static neutron stars. The axionic theory is considered in the regime in which the axion oscillates around its potential minimum, which cosmologically occurs post-i
Externí odkaz:
http://arxiv.org/abs/2403.09818
The significance of the electroweak phase transition is undeniable, and although initially it was believed that it was second-order, it is now believed that it is a first-order transition. However, it is not a strong first-order phase transition in t
Externí odkaz:
http://arxiv.org/abs/2403.01591
Autor:
Oikonomou, V. K.
In this work we aim to revive the interest for non-minimal derivative coupling theories of gravity, in light of the GW170817 event. These theories include a string motivated non-minimal kinetic term for the scalar field of the form $\sim \xi(\phi) G^
Externí odkaz:
http://arxiv.org/abs/2402.02050
In this work we shall prove that the tensor spectral index of the primordial tensor perturbations for GW170817-compatible Einstein-Gauss-Bonnet theories, takes the approximate simplified form $n_{\mathcal{T}}\simeq 2\left(-1+\frac{1}{\lambda(\phi)} \
Externí odkaz:
http://arxiv.org/abs/2402.02049
In this work we study the GW170817-compatible Einstein-Gauss-Bonnet theories during the reheating and the end of inflationary era. Given the scalar field potential $V(\phi)$ which can have some intrinsic importance for the theory, determining the sca
Externí odkaz:
http://arxiv.org/abs/2401.11273