scholarly journals 4D Einstein - Gauss - Bonnet Gravity with Nonlinear Electrodynamics: Entropy, Energy Emission, Quasinormal Modes and Deflection Angle

2021 ◽  
Author(s):  
Sergey Kruglov
Keyword(s):  
Deflection Angle ◽  
Quasinormal Modes ◽  
Einstein Equations ◽  
Nonlinear Electrodynamics ◽  
Energy Conditions ◽  
Model Parameters ◽  
Logarithmic Correction ◽  
Logarithmic Term ◽  
Bonnet Gravity ◽  
Energy Emission

The logarithmic correction to Bekenshtein$-$Hawking entropy in the framework of 4D Einstein - Gauss - Bonnet gravity coupled with nonlinear electrodynamics is obtained. We explore the black hole solution with the spherically symmetric metric. The logarithmic term in the entropy has a structure similar to the entropy correction in the semi-classical Einstein equations which mimics the quantum correction to the area low. The energy emission rate of black holes and energy conditions are studied. The quasinormal modes of a test scalar field are investigated. The gravitational lensing of light around BHs was studied. We calculated the deflection angle for some model parameters.

scholarly journals Einstein–Gauss–Bonnet Gravity with Nonlinear Electrodynamics: Entropy, Energy Emission, Quasinormal Modes and Deflection Angle

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 944
Author(s):  
Sergey Il’ich Kruglov
Keyword(s):  
Deflection Angle ◽  
Quasinormal Modes ◽  
Einstein Equations ◽  
Nonlinear Electrodynamics ◽  
Energy Conditions ◽  
Model Parameters ◽  
Logarithmic Correction ◽  
Logarithmic Term ◽  
Bonnet Gravity ◽  
Energy Emission

The logarithmic correction to Bekenshtein–Hawking entropy in the framework of 4D Einstein–Gauss–Bonnet gravity coupled with nonlinear electrodynamics is obtained. We explore the black hole solution with the spherically symmetric metric. The logarithmic term in the entropy has a structure similar to the entropy correction in the semi-classical Einstein equations. The energy emission rate of black holes and energy conditions are studied. The quasinormal modes of a test scalar field are investigated. The gravitational lensing of light around BHs was studied. We calculated the deflection angle for some model parameters.

scholarly journals 4d Einstein-Gauss-Bonnet Gravity With Nonlinear Electrodynamics: Entropy, Energy Emission, Quasinormal Modes and Deflection Angle

2021 ◽  
Author(s):  
Sergey Il'ich Kruglov
Keyword(s):  
Black Holes ◽  
Deflection Angle ◽  
Quasinormal Modes ◽  
Einstein Equations ◽  
Nonlinear Electrodynamics ◽  
Energy Conditions ◽  
Model Parameters ◽  
Logarithmic Correction ◽  
Bonnet Gravity ◽  
Energy Emission

The logarithmic correction to Bekenshtein-Hawking entropy in the framework of 4D Einstein$-$Gauss$-$Bonnet gravity coupled with nonlinear electrodynamics is obtained. We explore the black hole solution with the spherically symmetric metric. The logarithmic term in the entropy has a structure similar to the entropy correction in the semi-classical Einstein equations which mimics the quantum correction to the area low. The energy emission rate of black holes and energy conditions are studied. Quasinormal modes of black holes are investigated. The gravitational lensing of light around BHs was investigated. We calculated the deflection angle for some model parameters.

Extended GUP corrected thermodynamics, shadow radius and quasinormal modes of charged AdS black holes in Gauss–Bonnet gravity

2021 ◽  
pp. 2150137
Author(s):  
Shahid Chaudhary ◽  
Abdul Jawad ◽  
Kimet Jusufi ◽  
Muhammad Yasir
Keyword(s):  
Black Hole ◽  
Generalized Uncertainty Principle ◽  
Quasinormal Modes ◽  
Nonlinear Electrodynamics ◽  
Horizon Radius ◽  
Bonnet Gravity ◽  
Ads Black Holes ◽  
Dimensional Black Hole ◽  
Relationship Of ◽  
The Relationship

This paper explores the influence of special type of higher order generalized uncertainty principle on the thermodynamics of five-dimensional black hole in Einstein–Gauss–Bonnet gravity coupled to nonlinear electrodynamics. We examine the corrected thermodynamical properties of the black hole with some interesting limiting cases [Formula: see text] and [Formula: see text] and compared our results with usual thermodynamical relations. We observe that the influence of GUP correction stabilizes the BH and BH solution remains physical throughout the region of horizon radius. In this framework, we also uncover the relationship of shadow radius and quasinormal modes of the mentioned black hole. We conclude that shadow radius of our considered black hole is a perfect circle and it decreases with increasing values of charge and Gauss–Bonnet parameter. We also verify the inverse relation between the quasinormal modes frequencies and shadow radius, i.e. quasinormal modes should increase with increasing values of Gauss–Bonnet parameter and electric charge.

scholarly journals Nonlinear electrodynamics effects on the black hole shadow, deflection angle, quasinormal modes and greybody factors

2022 ◽  
Vol 2022 (01) ◽  
pp. 009
Author(s):  
M. Okyay ◽  
A. Övgün
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Deflection Angle ◽  
Magnetic Charge ◽  
Generalized Uncertainty Principle ◽  
Quasinormal Modes ◽  
Nonlinear Electrodynamics ◽  
Stable Region ◽  
Massless Scalar ◽  
The Deflection Angle

Abstract In this paper, we discuss the effects of nonlinear electrodynamics (NED) on non-rotating black holes, parametrized by the field coupling parameter β and magnetic charge parameter P in detail. Particularly, we survey a large range of observables and physical properties of the magnetically charged black hole, including the thermodynamic properties, observational appearance, quasinormal modes and absorption cross sections. Initially, we show that the NED black hole is always surrounded by an event horizon and any magnetic charge is permissible. We then show that the black hole gets colder with increasing charge. Investigating the heat capacity, we see that the black hole is thermally stable between points of phase transition. Introducing a generalized uncertainty principle (GUP) with a quantum gravity parameter λ extends the range of the stable region, but the effect on temperature is negligible. Then we compute the deflection angle at the weak field limit, by the Gauss-Bonnet theorem and the geodesic equation, and find that even at the first order, the magnetic charge has a contribution due to the “field mass” term. Small changes of the charge contributes greatly to the paths of null geodesics due to the P 2 dependence of the horizon radius. Using a ray-tracing code, we simulate the observational appearance of a NED black hole under different emission profiles, thin disk and spherical accretion. We find that the parameter P has a very strong effect on the observed shadow radius, in agreement with the deflection angle calculations. We finally consider quasinormal modes under massless scalar perturbations of the black hole and the greybody factor. We find that the charge introduces a slight difference in the fundamental frequency of the emitted waveform. We find that the greybody factor of the NED black hole is strongly steepened by the introduction of increasing charge. To present observational constrains, we show that the magnetic charge of the M87* black hole is between 0 ≤ P ≤ 0.024 in units of M, in agreement with the idea that real astrophysical black holes are mostly neutral. We also find that LIGO/VIRGO and LISA could detect NED black hole perturbations from BHs with masses between 5 M ☉ and 8.0 · 108 M ☉. We finally show that for black holes with masses detected with LIGO so far, charged NED black holes would deviate from Schwarzschild by 5∼10 Hz in their fundamental frequencies.

scholarly journals New Model of 4D Einstein–Gauss–Bonnet Gravity Coupled with Nonlinear Electrodynamics

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 249
Author(s):  
Sergey Il’ich Kruglov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Symmetric Solution ◽  
Emission Rate ◽  
Quasinormal Modes ◽  
Black Hole Thermodynamics ◽  
Nonlinear Electrodynamics ◽  
Spherically Symmetric ◽  
Bonnet Gravity ◽  
Spherically Symmetric Solution

New spherically symmetric solution in 4D Einstein–Gauss–Bonnet gravity coupled with nonlinear electrodynamics is obtained. At infinity, this solution has the Reissner–Nordström behavior of the charged black hole. The black hole thermodynamics, entropy, shadow, energy emission rate, and quasinormal modes of black holes are investigated.

BOUNDS ON f(G) GRAVITY FROM ENERGY CONDITIONS

2010 ◽  
Vol 25 (27) ◽  
pp. 2325-2332 ◽  
Author(s):  
PUXUN WU ◽  
HONGWEI YU
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Energy Density ◽  
Modified Gravity ◽  
Energy Conditions ◽  
Model Parameters ◽  
Effective Energy ◽  
Raychaudhuri Equation ◽  
Accelerating Expansion

The f(G) gravity is a theory to modify the general relativity and it can explain the present cosmic accelerating expansion without the need of dark energy. In this paper the f(G) gravity is tested with the energy conditions. Using the Raychaudhuri equation along with the requirement that the gravity is attractive in the FRW background, we obtain the bounds on f(G) from the SEC and NEC. These bounds can also be found directly from the SEC and NEC within the general relativity context by the transformations: ρ → ρm + ρE and p → pm + pE, where ρE and pE are the effective energy density and pressure in the modified gravity. With these transformations, the constraints on f(G) from the WEC and DEC are obtained. Finally, we examine two concrete examples with WEC and obtain the allowed region of model parameters.

scholarly journals Quantum Gravity Phenomenology from the Thermodynamics of Spacetime

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 50
Author(s):  
Ana Alonso-Serrano ◽  
Marek Liška
Keyword(s):  
Quantum Gravity ◽  
Big Bang ◽  
Einstein Equations ◽  
Logarithmic Term ◽  
Quantum Gravity Phenomenology ◽  
Gravity Effects ◽  
Energy Quantum ◽  
The Big Bang ◽  
Big Bang Singularity ◽  
Modified Dynamics

This work is based on the formalism developed in the study of the thermodynamics of spacetime used to derive Einstein equations from the proportionality of entropy within an area. When low-energy quantum gravity effects are considered, an extra logarithmic term in the area is added to the entropy expression. Here, we present the derivation of the quantum modified gravitational dynamics from this modified entropy expression and discuss its main features. Furthermore, we outline the application of the modified dynamics to cosmology, suggesting the replacement of the Big Bang singularity with a regular bounce.

scholarly journals Lifshitz scaling effects on the holographic p-wave superconductors coupled to nonlinear electrodynamics

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Mahya Mohammadi ◽  
Ahmad Sheykhi
Keyword(s):  
Critical Temperature ◽  
Energy Gap ◽  
Mass Parameter ◽  
Delta Function ◽  
P Wave ◽  
Nonlinear Electrodynamics ◽  
Model Parameters ◽  
Scaling Effects ◽  
Low Frequencies ◽  
The Real

AbstractWe employ gauge/gravity duality to study the effects of Lifshitz scaling on the holographic p-wave superconductors in the presence of Born–Infeld nonlinear electrodynamics. By using the shooting method in the probe limit, we calculate the relation between critical temperature $$T_\mathrm{{c}}$$ T c and $$\rho ^{z/d}$$ ρ z / d numerically for different values of mass, nonlinear parameter b and Lifshitz critical exponent z in various dimensions. We observe that critical temperature decreases by increasing b, z or the mass parameter m which makes conductor/superconductor phase transition harder to form. In addition, we analyze the electrical conductivity and find the behavior of the real and the imaginary parts as a function of frequency, which depend on the model parameters. However, some universal behaviors are seen. For instance at low frequencies, the real part of conductivity shows a delta function behavior, while the imaginary part has a pole, which means that these two parts are connected to each other through the Kramers–Kronig relation. The behavior of the real part of the conductivity in the large frequency regime can be achieved by $$\mathrm{{Re}}[\sigma ]=\omega ^{D-4}$$ Re [ σ ] = ω D - 4 . Furthermore, with increasing the Lifshitz scaling z, the energy gap and the minimum values of the real and imaginary parts become unclear.

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