Article
Physics, Particles & Fields
S. N. Sajadi, H. R. Safari
Summary: In this paper, we study uncharged, non-conformal, and anisotropic systems with strong interactions using gauge-gravity duality. We obtain an anisotropic black brane solution to a 5D Einstein-Gauss-Bonnet-Axion-Dilaton system at finite temperature and investigate its properties. We also explore transport and diffusion properties and determine the imaginary part of the heavy quark potential in a strongly coupled plasma dual to Gauss-Bonnet gravity.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
R. Hassannejad, A. Sadeghi, F. Shojai
Summary: In this paper, the 4-dimensional Einstein-Gauss-Bonnet (EGB) gravity is treated as general relativity with an effective stress-energy tensor. The modified Oppenheimer-Snyder-Datt model of the gravitational collapse of a star in a 4-dimensional EGB black hole is studied. The interior geometry of the star is described by the spatially flat Friedmann-Robertson-Walker metric, and the matter is uniformly distributed without any assumption about its equation of state. The time evolution of event and apparent horizons is also studied.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Physics, Particles & Fields
K. El Bourakadi, M. Ferricha-Alami, H. Filali, Z. Sakhi, M. Bennai
Summary: This study investigates the production of gravitational waves in an expanding Universe during the first stages following inflation, with a focus on the Gauss-Bonnet term's impact on inflationary parameters. The analysis on preheating parameters reveals sensitivity to various factors, including n and gamma. Results show good consistency between the gravitational wave energy density spectrum and observations, suggesting that the generation of gravitational waves during preheating can meet the constraints from Planck's data.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
M. Zubair, Muhammad Ali Raza, Furkat Sarikulov, Javlon Rayimbaev
Summary: In this study, we consider a static black hole immersed in the Power-Yang-Mills field in four-dimensional Einstein-Gauss-Bonnet gravity and investigate the effects of various parameters on the radius of the photon sphere. We use a modified form of the Newman-Janis algorithm to obtain a rotating black hole solution in this gravity. Furthermore, we explore the influence of the Yang-Mills magnetic charge Q with power q, Gauss-Bonnet parameter alpha, and spin a on the horizon radius. It is observed that all the parameters have a significant effect on the shadow and related physical observables. The constraint values for the spin, magnetic charge, and Gauss-Bonnet parameters are obtained using the shadow size of supermassive black holes from the EHT observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Mayukh R. Gangopadhyay, Hussain Ahmed Khan, Yogesh
Summary: In this study, the researchers investigated the application of Natural inflation and Mutated Hilltop inflation, two theoretically promising models of inflation, in the Einstein-Gauss Bonnet (EGB) gravity framework. By considering the observations from GW170817 that the speed of gravitational wave is equal to the speed of light, they explored the new features in the effective potential due to the non-minimal coupling to the Gauss-Bonnet invariant in the action. The analysis not only focused on the inflationary dynamics, but also examined the reheating dynamics and the energy spectrum of the gravitational wave.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Hai-Shan Liu, H. Lu, Zi-Yu Tang, Bin Wang
Summary: A higher-derivative gravity theory is proposed, as an extension of the Starobinsky model, which introduces new black holes carrying massive scalar hair. These black holes are found to act as walls separating naked spacetime singularities and wormholes, with the entropy and temperature being the same for both the new hairy black hole and the Schwarzschild black hole at the same mass.
Article
Astronomy & Astrophysics
Gulmina Zaman Babar, Farruh Atamurotov, Abdullah Zaman Babar
Summary: This paper explores gravitational lensed photons in a 4 dimensional Einstein-Gauss-Bonnet gravity under weak-field regime, investigating lensing angle and image source brightness magnification in different paradigms. The results are compared with the standard Schwarzschild geometry.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Astronomy & Astrophysics
Eugeny Babichev, William T. Emond, Sabir Ramazanov
Summary: We study black holes in a modified gravity scenario involving a scalar field quadratically coupled to the Gauss-Bonnet invariant. The nonminimal coupling to gravity leads to symmetry restoration near the black hole horizon, prompting the development of the scalar wall in its vicinity. The model is fully consistent with the existence of an inflationary stage and predicts the speed of gravitational waves to be extremely close to unity.
Article
Astronomy & Astrophysics
Yaser Tavakoli, Ahad K. Ardabili, Mariam Bouhmadi-Lopez, Paulo Vargas Moniz
Summary: This study investigates the combined effect of DGP induced gravity and GB curvature on the OS dynamics. The results show that in this modified OS scenario, there may be central shell-focusing singularities or sudden collapse singularities. The study also explores the deviations of the exterior spacetime from the standard Schwarzschild geometry and finds the possibility of naked singularities.
Article
Physics, Nuclear
Kimet Jusufi
Summary: Using a modified expression for the electric potential in the context of T-duality, an exact charged solution is obtained within the 4D Einstein-Gauss-Bonnet (4D EGB) theory of gravity in the presence of a cosmological constant. The solution is also shown to exist in the regularized 4D EGB theory, and a correspondence between the black hole solution in the 4D EGB theory and the solution in the non-relativistic Horava-Lifshitz theory is pointed out. The black hole solution is regular and singularity-free, and a class of well known solutions in the literature is derived as a special case.
Article
Physics, Particles & Fields
Sajal Mukherjee, Naresh Dadhich
Summary: In this study, an exact Lambda-vacuum solution with NUT charge in six dimension in pure Gauss-Bonnet gravity is obtained, with the horizon topology having a product structure of S-(2) x S-(2). The analysis of horizon and singularity structure leads to parameter windows for the physical viability of the solution. It is found that for the curvatures to remain a function of r alone for NUT black hole spacetime, the horizon topology must be a product of S-(2) spheres.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
M. Bousder, M. Bennai
Summary: This study investigates the charge of the 4D-Einstein-Gauss-Bonnet black hole by examining the charge of a particle-antiparticle pair at r(-) and r(+) horizons, showing the existence of two types of Schwarzschild black holes and quantified values for the Einstein-Gauss-Bonnet black hole charge. The study also reveals the Hawking-Bekenstein formula with two logarithmic corrections, where the second correction depends on the cosmological constant and the black hole charge. Finally, the thermodynamics of the EGB-AdS black hole is explored.
Article
Physics, Multidisciplinary
Doris Samart, Phongpichit Channuie
Summary: This paper investigates the thermal phase transition from asymptotic anti-de Sitter to de Sitter geometries in the context of four-dimensional Einstein-Gauss-Bonnet gravity, showing that the transitions occur within a narrow coupling range.
ANNALEN DER PHYSIK
(2022)
Article
Astronomy & Astrophysics
Sandipan Sengupta
Summary: In this study, we establish an Einstein-Gauss-Bonnet theory in four dimensions based on extra dimensions with vanishing metrical length. The effective field equations of the theory depend solely on the four-metric and exhibit a quadratic curvature nonlinearity without higher than second-order derivatives. Unlike previous proposals, our formalism does not require classical regularization of divergences and is not equivalent to Horndeski gravity. The theory is generally covariant and independent of compactification. The vacuum field equations allow for FLRW cosmologies with nonsingular bounce and self-accelerating Universe, as well as spherically symmetric black holes more general than Schwarzschild. Furthermore, the quadratic theory of gravity remains valid against the inclusion of higher Lovelock densities in 5 + 2n dimensions.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
S. N. Sajadi
Summary: In this paper, we extend the AdS/QCD model to quadratic gravity to study the influence of gravity. We find an anisotropic black brane solution in a 5D Einstein-Gauss-Bonnet-two Maxwell-dilaton system. The system is characterized by an arbitrary exponent, a dilaton field, a time component of the first Maxwell field, and a magnetic component of the second Maxwell field. We investigate three cases and consider the effects of the theory parameter and the anisotropic parameter. The blackening function exhibits a thermodynamic phase transition between small/large and AdS/large black brane with suitable chemical potential and other parameters.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Multidisciplinary
Saso Grozdanov, Wilke van der Schee
PHYSICAL REVIEW LETTERS
(2017)
Article
Physics, Multidisciplinary
Saso Grozdanov, Koenraad Schalm, Vincenzo Scopelliti
PHYSICAL REVIEW LETTERS
(2018)
Article
Physics, Multidisciplinary
Jorge Casalderrey-Solana, Saso Grozdanov, Andrei O. Starinets
PHYSICAL REVIEW LETTERS
(2018)
Article
Physics, Particles & Fields
Mike Blake, Richard A. Davison, Saso Grozdanov, Hong Liu
JOURNAL OF HIGH ENERGY PHYSICS
(2018)
Article
Physics, Particles & Fields
Saso Grozdanov
JOURNAL OF HIGH ENERGY PHYSICS
(2019)
Article
Physics, Multidisciplinary
Saso Grozdanov, Pavel K. Kovtun, Andrei O. Starinets, Petar Tadic
PHYSICAL REVIEW LETTERS
(2019)
Article
Physics, Particles & Fields
Saso Grozdanov, Andrei O. Starinets
JOURNAL OF HIGH ENERGY PHYSICS
(2019)
Article
Physics, Particles & Fields
Saso Grozdanov, Napat Poovuttikul
JOURNAL OF HIGH ENERGY PHYSICS
(2019)
Article
Physics, Particles & Fields
Saso Grozdanov, Pavel K. Kovtun, Andrei O. Starinets, Petar Tadic
JOURNAL OF HIGH ENERGY PHYSICS
(2019)
Article
Physics, Particles & Fields
Asmund Folkestad, Saso Grozdanov, Krishna Rajagopal, Wilke van der Schee
JOURNAL OF HIGH ENERGY PHYSICS
(2019)
Article
Astronomy & Astrophysics
Saso Grozdanov, Andrew Lucas, Napat Poovuttikul
Article
Physics, Fluids & Plasmas
Saso Grozdanov, Koenraad Schalm, Vincenzo Scopelliti
Article
Astronomy & Astrophysics
Saso Grozdanov, Napat Poovuttikul
Article
Materials Science, Multidisciplinary
Ivan Kukuljan, Saso Grozdanov, Tomaz Prosen
Article
Astronomy & Astrophysics
Saso Grozdanov, Diego M. Hofman, Nabil Iqbal