Zobrazeno 1 - 10
of 58
pro vyhledávání: '"Papageorgiou, Alexandros"'
Axion-inflation models are a compelling candidate as a mechanism behind the accelerated expansion in the early universe in light of the possibility to embed them in higher dimensional UV complete theories and the exciting prospect of testing them wit
Externí odkaz:
http://arxiv.org/abs/2405.14963
We consider the case of axion-like particles (ALPs) during inflation. When coupled to a non-Abelian gauge sector via a Chern-Simons term, ALPs support an intriguing, testable, phenomenology with very distinctive features including chiral primordial g
Externí odkaz:
http://arxiv.org/abs/2403.13581
We study the impact of gravitational wave memory on the distribution of far away light sources in the sky. For the first time we compute the built up of small, but permanent tensor distortions of the metric over cosmological time-scales using realist
Externí odkaz:
http://arxiv.org/abs/2403.07614
We use a large set of halo mass function (HMF) models in order to investigate their ability to represent the observational Cluster Mass Function (CMF), derived from the $\mathtt{GalWCat19}$ cluster catalogue, within the $\Lambda$CDM cosmology. We app
Externí odkaz:
http://arxiv.org/abs/2311.09826
We demonstrate that the recently announced signal for a stochastic gravitational wave background (SGWB) from pulsar timing array (PTA) observations, if attributed to new physics, is compatible with primordial GW production due to axion-gauge dynamics
Externí odkaz:
http://arxiv.org/abs/2307.02322
Publikováno v:
Phys. Rev. D 109 (2024) L101303
We study an inflation model with a flat scalar potential supported by observations and find that slow-roll inflation can emerge after a quasi-cyclic phase of the Universe, where it undergoes repeated expansions and contractions for a finite time peri
Externí odkaz:
http://arxiv.org/abs/2305.02366
Publikováno v:
Phys. Rev. D 109 (2024) 103523
Inflationary models, especially those with plateau-type potentials, are consistent with the cosmological data, but inflation itself does not resolve the initial singularity. This singularity is resolved, for example, by the idea of the quantum creati
Externí odkaz:
http://arxiv.org/abs/2305.02367
The coupling between a pseudo-scalar inflaton and a gauge field leads to an amount of additional density perturbations and gravitational waves (GWs) that is strongly sensitive to the inflaton speed. This naturally results in enhanced GWs at (relative
Externí odkaz:
http://arxiv.org/abs/2303.13425
We study a number of well-motivated theories of modified gravity with the common overarching theme that they predict the existence of compact objects such as black holes and wormholes endowed with scalar hair. We compute the shadow radius of the resu
Externí odkaz:
http://arxiv.org/abs/2210.17533
Publikováno v:
JHEP 01 (2023) 169
We study the impact of sphaleron-induced thermal friction on the axion dark-matter abundance due to the interaction of an axion-like particle (ALP) with a dark non-abelian gauge sector in a secluded thermal bath. Thermal friction can either enhance t
Externí odkaz:
http://arxiv.org/abs/2206.01129