359 citations · 1.3k across the 40 of their papers we have counts for
41 papers
Magnetically assisted primordial scalar perturbations: Scalar-Induced Gravitational Waves
Arko Bhaumik, Theodoros Papanikolaou, Anish Ghoshal
Primordial magnetic fields (PMFs) provide a well-motivated source of cosmological perturbations through their anisotropic stress and may leave observable imprints in both the scala…
Inflation driven by repulsive-like primordial black holes
Konstantinos Dialektopoulos, Theodoros Papanikolaou, Vasilios Zarikas
We review a new natural inflationary mechanism operated by repulsive-like primordial black holes (PBHs). In particular, working within the ``Swiss - Cheese" cosmological framework,…
Primordial black hole formation from transient cosmology
Gerasimos Kouniatalis, Theodoros Papanikolaou, Spyros Basilakos +1
We study primordial black hole (PBH) formation in a minimally coupled teleparallel cosmology that generates a transient departure from standard radiation domination. The mod…
Ultra-fast growth of primordial black holes through radiative absorption
Dimitris S. Kallifatides, Theodoros Papanikolaou, Emmanuel N. Saridakis
We show that Schwarzschild primordial black holes (PBHs) formed in the radiation-dominated era can grow extremely rapidly through governed by the fu…
Primordial black hole dark matter from ultra-slow-roll inflation in Horndeski gravity
Despina Totolou, Theodoros Papanikolaou, Emmanuel N. Saridakis
Primordial black holes (PBHs) provide a well-motivated non-particle candidate for dark matter, requiring an enhancement of curvature perturbations on small inflationary scales cons…
Primordial black hole driven cosmic acceleration
Konstantinos Dialektopoulos, Theodoros Papanikolaou, Vasilios Zarikas
We propose a natural mechanism for cosmic acceleration driven by primordial black holes (PBHs) with repulsive behavior, within a ''Swiss Cheese'' cosmological framework. Considerin…
Primordial black hole induced gravitational waves in gravity
Theodoros Papanikolaou, Salvatore Capozziello
Ultra-light primordial black holes (PBHs) with masses can trigger an early matter-dominated (eMD) era before Big Bang Nucleosynthesis (BBN…
Gravitational wave signatures of non-singular matter bouncing cosmology in NANOGrav and beyond
Theodoros Papanikolaou
Non-singular matter bouncing cosmological setups are of particular interest since apart from adressing the initial singularity problem they can give rise as well to a nearly scale-…
Induced Gravitational Waves as Cosmic Tracers of Leptogenesis
Marco Chianese, Guillem Domènech, Theodoros Papanikolaou +2
We demonstrate that induced gravitational waves (IGWs) can naturally emerge within well-motivated realizations of thermal leptogenesis, thereby providing a possible observational h…
Vector induced Gravitational Waves sourced by Primordial Magnetic Fields
Arko Bhaumik, Theodoros Papanikolaou, Anish Ghoshal
In this work, we develop a generic formalism for the study of tensor perturbations induced at second order by first-order vector metric perturbations, dubbing these induced tensor…
Primordial black holes as cosmic expansion accelerators
Konstantinos Dialektopoulos, Theodoros Papanikolaou, Vasilios Zarikas
We propose a novel and natural mechanism for cosmic acceleration driven by primordial black holes (PBHs) exhibiting repulsive behavior. Using a new ``Swiss Cheese'' cosmological ap…
Reconstructing Primordial Curvature Perturbations via Scalar-Induced Gravitational Waves with LISA
Jonas El Gammal, Aya Ghaleb, Gabriele Franciolini +17
Many early universe scenarios predict an enhancement of scalar perturbations at scales currently unconstrained by cosmological probes. These perturbations source gravitational wave…
Is inflationary magnetogenesis sensitive to the post-inflationary history ?
Konstantinos Dimopoulos, Anish Ghoshal, Theodoros Papanikolaou
Considering inflationary magnetogenesis induced by time-dependent kinetic and axial couplings of a massless Abelian vector boson field breaking the conformal invariance we show in…
Gravitational wave signatures from reheating in Chern-Simons running-vacuum cosmology
Charalampos Tzerefos, Theodoros Papanikolaou, Spyros Basilakos +2
Within the context of a Chern-Simons running-vacuum-model (RVM) cosmology, one expects an early-matter dominated (eMD) reheating period after RVM inflation driven by the axion fiel…
Gravitational waves from primordial black hole isocurvature: the effect of non-Gaussianities
Xin-Chen He, Yi-Fu Cai, Xiao-Han Ma +3
Ultra-light primordial black holes (PBHs) with masses can dominate transiently the energy budget of the Universe and reheat the Universe throug…
Gravitational-wave signatures of gravito-electromagnetic couplings
Theodoros Papanikolaou, Charalampos Tzerefos, Salvatore Capozziello +1
Gravitational waves (GWs) can undoubtedly serve as a messenger from the early Universe acting as well as a novel probe of the underlying gravity theory. In this work, motivated by…
Observable Signatures of No-Scale Supergravity in NANOGrav
Spyros Basilakos, Dimitri V. Nanopoulos, Theodoros Papanikolaou +2
In light of NANOGrav data we provide for the first time possible observational signatures of Superstring theory. Firstly, we work with inflection-point inflationary potentials natu…
Primordial black holes and induced gravitational waves in non-singular matter bouncing cosmology
Theodoros Papanikolaou, Shreya Banerjee, Yi-Fu Cai +2
We present a novel model-independent generic mechanism for primordial black hole formation within the context of non-singular matter bouncing cosmology. In particular, considering…
New probe of non-Gaussianities with primordial black hole induced gravitational waves
Theodoros Papanikolaou, Xin-Chen He, Xiao-Han Ma +3
We propose a new probe of primordial non-Gaussianities (NGs) through the observation of gravitational waves (GWs) induced by ultra-light () primordial…
Revisiting string-inspired running-vacuum models under the lens of light primordial black holes
Theodoros Papanikolaou, Charalampos Tzerefos, Spyros Basilakos +2
Light primordial black holes (PBHs) with masses can interestingly dominate the Universe's energy budget and give rise to early matter-dominated (eMD…
Primordial black holes and their gravitational-wave signatures
Eleni Bagui, Sebastien Clesse, Valerio De Luca +17
In the recent years, primordial black holes (PBHs) have emerged as one of the most interesting and hotly debated topics in cosmology. Among other possibilities, PBHs could explain…
Induced gravitational waves from flipped SU(5) superstring theory at
Spyros Basilakos, Dimitri V. Nanopoulos, Theodoros Papanikolaou +2
The no-scale flipped SU(5) superstring framework constitutes a very promising paradigm for physics below the Planck scale providing us with a very rich cosmological phenomenology i…
Gravitational wave signatures of no-scale Supergravity in NANOGrav and beyond
Spyros Basilakos, Dimitri V. Nanopoulos, Theodoros Papanikolaou +2
In this Letter, we derive for the first time a characteristic three-peaked GW signal within the framework of no-scale Supergravity, being the low-energy limit of Superstring theory…
Constraining supermassive primordial black holes with magnetically induced gravitational waves
Theodoros Papanikolaou, Konstantinos N. Gourgouliatos
Primordial black holes (PBHs) can answer a plethora of cosmic conundra, among which the origin of the cosmic magnetic fields. In particular, supermassive PBHs with masses $M_\mathr…