Grigoris Panotopoulos

Prof. Dr. Grigoris Panotopoulos

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Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 October 2017 in Physical Review D
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Grigoris PanotopoulosGrigoris Panotopoulos
Grigoris Panotopoulos
Ilídio LopesIlídio Lopes
Ilídio Lopes
In this work, we apply relativistic mean-field theory in neutron stars assuming that fermionic dark matter is trapped inside the star and interacts directly with neutrons by exchanging standard model Higgs bosons. For realistic values of the parameters of the model, we compute numerically the equation of state, and we compare it to the standard one. Furthermore, the mass-to-radius relation for both equations of state (pure neutron matter as well as admixed DM-neutron star) is shown, and the highest star mass for both cases is reported.

24 January 2018 in Physical Review D
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ARAngel Rincon
Angel Rincon
Grigoris PanotopoulosGrigoris Panotopoulos
Grigoris Panotopoulos
We study for the first time the stability against scalar perturbations, and we compute the spectrum of quasinormal modes of three-dimensional charged black holes in Einstein-power-Maxwell nonlinear electrodynamics assuming running couplings. Adopting the sixth order Wentzel-Kramers-Brillouin (WKB) approximation we investigate how the running of the couplings change the spectrum of the classical theory. Our results show that all modes corresponding to nonvanishing angular momentum are unstable both in the classical theory and with the running of the couplings, while the fundamental mode can be stable or unstable depending on the running parameter and the electric charge.

23 October 2018 in The European Physical Journal C
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Grigoris PanotopoulosGrigoris Panotopoulos
Grigoris Panotopoulos
ARAngel Rincon
Angel Rincon
We find new exact analytical solutions in three-dimensional gravity applying the Minimal Geometric Deformation approach in a cloud of strings.

25 July 2017 in The European Physical Journal C
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ARAngel Rincon
Angel Rincon
ECErnesto Contreras
Ernesto Contreras
PBPedro Bargueño
Pedro Bargueño
BKBenjamin Koch
Benjamin Koch
Grigoris PanotopoulosGrigoris Panotopoulos
Grigoris Panotopoulos
AHAlejandro Hernández-Arboleda
Alejandro Hernández-Arboleda
In the present work we study the scale dependence at the level of the effective action of charged black holes in Einstein–Maxwell as well as in Einst

24 March 2020 in Physical Review D
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ECErnesto Contreras
Ernesto Contreras
ARAngel Rincon
Angel Rincon
Grigoris PanotopoulosGrigoris Panotopoulos
Grigoris Panotopoulos
Pedro BarguenoPedro Bargueno
Pedro Bargueno
BKBenjamin Koch
Benjamin Koch
In this work, starting from a spherically symmetric scale-dependent black hole, a rotating solution is obtained by following the Newman–Janis algorithm without complexification. Besides studying the horizon, the static conditions and causality issues of the rotating solution, we get and discuss the shape of its shadow.

25 March 2020 in Physical Review D
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Violetta SagunVioletta Sagun
Violetta Sagun
Grigoris PanotopoulosGrigoris Panotopoulos
Grigoris Panotopoulos
Ilídio LopesIlídio Lopes
Ilídio Lopes
We study radial oscillations of non-rotating neutron stars (NSs) in four-dimensional general relativity. The interior of the NS was modeled within a recently proposed multicomponent realistic equation of state (EoS) with the induced surface tension (IST). In particular, we considered the IST EoS with two sets of model parameters, that both reproduce all the known properties of normal nuclear matter, give a high quality description of the proton flow constraint, hadron multiplicities created in nuclear-nuclear collisions, consistent with astrophysical observations and the observational data from the NS-NS merger. We computed the 12 lowest radial oscillation modes, their frequencies and corresponding eigenfunctions, as well as the large frequency separation for six selected fiducial NSs (with different radii and masses of 1.2, 1.5 and 1.9 solar masses) of the two distinct model sets. The calculated frequencies show their continuous growth with an increase of the NS central baryon density. Moreover, we found correlations between the behavior of the first eigenfunction calculated for the fundamental mode, the adiabatic index and the speed of sound profile, which could be used to probe the internal structure of NSs with the asteroseismology data.