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İzzet Sakallı

Publications and source records attributed to İzzet Sakallı.

At least 73 records · Page 4Linked to original sources

Nonlinear Einstein-Power-Yang-Mills AdS Black Holes: From Quantum Tunneling to Aschenbach Effect

This study investigates the thermodynamic and quantum properties of Einstein-Power-Yang-Mills (EPYM) black holes in an Anti-de Sitter background, focusing on the effects of the nonlinear Yang-Mills charge parameter $γ$. We derive the metric function, analyze Hawking radiation through boson tunneling, and calculate thermodynamic properties including temperature and phase transitions. The quantum tunneling of $W^+$ bosons is examined using the WKB approximation and Hamilton-Jacobi formalism, revealing how nonlinearity modifies the radiation spectrum. We compute the effective potential governing photon orbits and null geodesics, demonstrating significant alterations in light behavior in strong gravitational fields. Additionally, we explore the Aschenbach effect, showing that this phenomenon, which is typically associated with rotating black holes, can emerge in spherically symmetric EPYM spacetimes because of non-linear field interactions. Our results may yield observational markers that can be identified with instruments such as the Event Horizon Telescope and upcoming gravitational wave detectors.

physics.gen-ph↗

Information Theoretical Approach to Detecting Quantum Gravitational Corrections

One way to test quantum gravitational corrections is through black hole physics. In this paper, We investigate the scales at which quantum gravitational corrections can be detected in a black hole using information theory. This is done by calculating the Kullback-Leibler divergence for the probability distributions obtained from the Parikh-Wilczek formalism. We observe that the quantum gravitational corrections increase the Kullback-Leibler divergence as the mass of the black hole decreases, which is expected as quantum gravitational corrections can be neglected for larger black holes. However, we further observe that after a certain critical value, quantum gravitational corrections tend to decrease again as the mass of the black hole decreases. To understand the reason behind this behavior, we explicitly obtain Fisher information about such quantum gravitational corrections and find that it also increases as the mass decreases, but again, after a critical value, it decreases. This is because at such a scale, quantum fluctuations dominate the system and we lose information about the system. We obtain these results for higher-dimensional black holes and observe this behavior for Kullback-Leibler divergence and Fisher information depending on the dimensions of the black hole. These results can quantify the scale dependence and dimension dependence of the difficulty in detecting quantum gravitational corrections.

hep-th↗

Dynamics of test particles and scalar perturbations around Ayón-Beato-García black hole coupled with cloud of strings

In this paper, we investigate the geodesic motion and scalar perturbations of the Ayón-Beato-García (ABG) black hole (BH) coupled with a cloud of strings (CS). By employing the effective potential approach, we analyze the trajectories of massless and massive test particles around this regular BH solution. The interplay between nonlinear electrodynamics (NLED) and CS significantly modifies the spacetime geometry, resulting in distinct dynamical properties for test particles. The behavior of null and timelike geodesics, including their stability and escape conditions, is thoroughly examined. In addition to the geodesic analysis, we study scalar perturbations by deriving the Klein-Gordon equation for massless scalar fields in this spacetime. The resulting Schrödinger-like wave equation reveals an effective potential that depends intricately on the NLED and CS parameters. Furthermore, we compute the greybody factors (GFs) to explore the energy transmission and absorption properties of theBH. Our results demonstrate that the NLED parameter $g$ and the CS parameter $α$ play pivotal roles in modulating the GFs, influencing the energy spectrum of scalar radiation. These results provide significant understanding of the observational characteristics of the ABG NLED-CS BH in astrophysical contexts.

gr-qc↗

Review Article: Integral Role of Physics in Advancing Pharmacy Education and Research

Physics plays a fundamental role in advancing pharmacy education and research, providing theoretical underpinnings and practical tools necessary to address complex challenges in drug development, delivery, and diagnostics. This review explores the integration of physics into the pharmacy curriculum, highlighting how principles such as fluid dynamics, thermodynamics, and spectroscopy (Tokgoz and Sakalli, 2018) enhance students' critical thinking and problem-solving skills. Additionally, it examines the pivotal contributions of physics to pharmaceutical research, including molecular modeling, imaging technologies like MRI and PET, and nanotechnology-driven drug delivery systems. Despite challenges in interdisciplinary collaboration and resource allocation, innovative teaching strategies and laboratory based learning are shown significant promise. Looking forward, the convergence of artificial intelligence and physics, as highlighted by recent Nobel Prize achievements in attosecond physics and bioorthogonal chemistry, is set to revolutionize pharmaceutical sciences, offering unprecedented precision and efficiency in drug discovery and personalized medicine.

physics.med-ph↗

Scalar, Vector Perturbations and Effective Hawking Radiation of Cylindrical Black Holes in $f(\mathcal{R})$ and Ricci-Inverse Gravity

This paper investigates scalar perturbations and quasinormal modes (QNMs) associated with cylindrical black holes constructed within the frameworks of $f(\mathcal{R})$-gravity and Ricci-Inverse ($\mathcal{RI}$) gravity. Moreover, we study the modified Hawking radiation in these black hole solutions and analyze the effects of coupling constants. These modified theories, which extend general relativity by introducing higher-order curvature corrections and additional geometric terms, provide a rich platform for exploring deviations from standard gravitational physics. The study begins by revisiting the cylindrical black holes in these modified gravity theories, where the effective cosmological constants respectively, are represented by $Λ_m^{f(\mathcal{R})}$ and $Λ_m^{\mathcal{RI}}$ related to the coupling constants unique to each framework. Afterwards, the QNMs, intrinsic damped oscillations of the black hole space-time, are analyzed to probe the stability of the system, with the effective potential $V$ revealing the impact of the modified gravity parameters. Additionally, the thermodynamic properties of the black holes are examined through the lens of the Generalized Uncertainty Principle (GUP), which introduces quantum corrections to Hawking radiation. The GUP-modified Hawking temperature and entropy are derived, demonstrating significant deviations from classical results and highlighting the quantum gravitational effects in these modified frameworks. By linking QNMs, thermodynamics, and quantum corrections, this work not only deepens the understanding of modified gravity theories but also offers potential observational pathways to test their validity.

gr-qc↗

Spin-dependent Regge-Wheeler Potential and QNMs in Quantum Corrected AdS Black Hole with Phantom Global Monopoles

In this paper, we investigate the geodesic motion of test particles in the spacetime surrounding a static, spherically symmetric black hole, which is described by an AdS-Schwarzschild-like metric and incorporates a quantum correction. This black hole also features phantom global monopoles, which modify the structure of the black hole space-time. We begin by deriving the effective potential governing the motion of test particles in this system and carefully analyze the impact of quantum correction in the presence of both phantom and ordinary global monopoles. Furthermore, we extend our study to include the spin-dependent Regge-Wheeler (RW) potential, which characterizes the dynamics of perturbations in this quantum-corrected black hole background. By examining this RW potential for various spin fields, we show how quantum corrections affect its form in the presence of both phantom and ordinary global monopoles. Our analysis demonstrate that quantum correction significantly alter the nature of the RW-potential, influencing the stability, and behavior of test particles and perturbations around the black hole.

gr-qc↗

Quasinormal Modes and GUP-Corrected Hawking Radiation of BTZ Black Holes within Modified Gravity Frameworks

This paper aims to explore the quasinormal modes (QNMs) and effective potential profiles of massless and rotating BTZ black holes within the frameworks of $f(\mathcal{R})$ and Ricci-Inverse ($\mathcal{RI}$) modified gravity theories, which, while producing similar space-time structures, exhibit variations due to distinct cosmological constants, $Λ_m$. We derive wave equations for these black hole perturbations and analyze the behavior of the effective potential $V_{\text{eff}}(r)$ under different values of mass $m$, cosmological constant $Λ_m$, and modified gravity parameters $α_1$, $α_2$, $β_1$, $β_2$, and $γ$. The findings indicate that increasing mass and parameter values results in a raised potential barrier, implying stronger confinement of perturbations and impacting black hole stability. Incorporating the generalized uncertainty principle, we also study its effect on the thermodynamics of rotating BTZ black holes, demonstrating how GUP modifies black hole radiation, potentially observable in QNM decay rates. Additionally, we investigate the motion of particles through null and timelike geodesics in static BTZ space-time, observing asymptotic behaviors for null geodesics and parameter-dependent shifts in potential for timelike paths. The study concludes that modified gravity parameters significantly influence QNM frequencies and effective potential profiles, offering insights into black hole stability and suggesting that these theoretical predictions may be tested through gravitational wave observations.

gr-qc↗

Thermodynamic Topology, Photon Spheres, and Evidence for Weak Gravity Conjecture in Charged Black Holes with Perfect Fluid within Rastall Theory

In this paper, we explore the Weak Gravity Conjecture (WGC) within the context of photon spheres in charged black holes, framed by Perfect Fluid in Rastall Theory. We aim to validate the WGC by identifying the extremality states of these black holes. We highlight the interplay between quantum dynamics and gravitational forces, opening new avenues in high-energy physics and quantum gravity. Our analysis reveals significant system changes with varying perfect fluid intensity $(α)$ and Rastall parameters ( $k$ and $λ$ ). For dust field $(ω=0)$, the WGC is met in extremality $(T=0)$ with $(Q / M)_{\text {ext }}>1$, indicating a black hole due to the presence of photon spheres (PS) with a total charge-1. However, further increases in $k$ and $λ$ or decreases $(α)$ lead to $P S=0$ that determines a singularity, not a black hole. We observed that the radiation field $(ω=1 / 3)$, quintessence field ( $ω=-2 / 3$ ), and phantom fields field ( $ω=-4 / 3$ ) also confirmed the WGC and maintaining a total charge of $P S=-1$ in some regions of the free parameters. Our numerical solutions identify points satisfying the WGC, establishing a bridge between quantum and cosmic realms. The results are summarized in Table (I). We also examine Duans topological current $ϕ$-mapping theory by analyzing generalized Helmholtz free energy methods to study the topological classes of our black hole. We reveal that for given values of the free parameters, the total topological numbers $(W=0)$ exist for the generalized Helmholtz free energy method for $ω=0,1 / 3,-2 / 3,-4 / 3$.

hep-th↗

Non-perturbative correction on the black hole geometry

In this paper, we use the holographic principle to obtain a modified metric of black holes that reproduces the exponentially corrected entropy. The exponential correction of the black hole entropy comes from non-perturbative corrections. It interprets as a quantum effect which affects black hole thermodynamics especially in the infinitesimal scales. Hence, it may affect black hole stability at the final stage. Then, we study modified thermodynamics due to the non-perturbative corrections and calculate thermodynamics quantities of several non-rotating black holes.

gr-qc↗

On thermal fluctuations and quantum regularities of $\mathcal{F}(R,\mathcal{G})$ gravity black holes with constant topological Euler density in nonlinear electrodynamics

We discuss the corrected thermodynamics and naked singularity structure of the topological static spherically symmetric solution in $\mathcal{F}(R,\mathcal{G})$ - gravity coupled with Born-Infeld - like nonlinear electrodynamics. Solutions admitting black holes with constant topological Euler density is analyzed in view of various thermodynamical variables. The inclusion of logarithmic correction to the entropy is extended to the other thermodynamical variables and the contribution of corrected variables are displayed on various plots. The stability of black hole under the effect of thermal variables is also studied. As a second scope of this study, solutions admitting timelike naked singularity are probed with bosonic and fermionic quantum wave packets to see if the singularity is quantum mechanically regular or not. In this context, the evolution of these probes remains well-defined if the corresponding spatial Hamiltonian operator is essentially self-adjoint. Our calculations reveal that when the singularity is probed with specific wave modes involving spin - $0$ and spin - $1/2$ quantum wave packets, the corresponding wave operators turn out to be essentially self-adjoint, which in turn implies unique well-defined time evolution.

hep-th↗

Exploring Non-perturbative Corrections in Thermodynamics of Static Dirty Black Holes

This study presents an investigation into the thermodynamic properties of a dirty black hole immersed in a uniform electric field within the framework of the Einstein-Nonlinear Electrodynamics (ENE)-dilaton theory. The analysis delves into various thermodynamic aspects, including heat capacity, Helmholtz free energy, and internal energy, providing insights into the behavior of the black hole under the influence of the electric field. Furthermore, the article explores the intricate interplay between quantum effects and thermodynamic behavior through the examination of quantum-corrected entropy. The study aims to shed light on the non-perturbative corrections that arise in this complex system, offering a comprehensive understanding of the modified thermodynamics of dirty black holes within the specified theoretical framework.

hep-th↗

Some Observable Physical Properties of the Higher Dimensional dS/AdS Black Holes in Einstein-Bumblebee Gravity Theory

We study the greybody factors, quasinormal modes, and shadow of the higher dimensional de-Sitter (dS)/ anti de-Sitter (AdS) black hole spacetimes derived from the Einstein-bumblebee gravity theory within the Lorentz symmetry breaking (LSB) framework. We specifically apply the semi-analytical WKB method and the time domain approach to study the scalar and Dirac perturbations of the black hole. In-depth researches are done on the effects of the LSB and dimensionality on the bosonic/fermionic greybody factors, quasinormal modes, and shadow of the higher dimensional bumblebee black hole. The results obtained are discussed, tabulated, and illustrated graphically.

hep-th↗

Superradiant (In)stability, Greybody Radiation, and Quasinormal Modes of Rotating Black Holes in non-linear Maxwell f (R) Gravity

The research of superradiant instability in the realm of quantum gravity is a well-known topic, with many physicists and astronomers studying the potential impact it can have on gravitational waves, the structure of the universe, and spacetime itself. In this work, we investigate the superradiant (in)stability of a rotating black hole obtained from the nonlinear Maxwell $f(R)$ gravity theory. In this study, the evaluation of stability/instability is going to be based on non-existence and existence of magnetic field, when the magnetic field constant becomes $c_{4}=0$ and $c_{4}\neq 0$, respectively. The analyzes of greybody factor (GF) and quasinormal modes (QNMs) are investigated in the stationary black hole spacetime both in the absence and presence of the magnetic field parameter. To this end, we first consider the Klein-Gordon equation for the complex scalar field in the geometry of that rotating black hole. In the sequel, the obtained radial equation is reduced to a one-dimensional Schrödinger-like wave equation with an effective potential energy. The effects of the nonlinear Maxwell $f(R)$ gravity theory parameters ($q$, $c$, and $c_{4}$) on the effective potential, GFs, and QNMs are thoroughly investigated. The obtained results show that even though the factors $q$, $c$, and $c_{4}$ all affect the effective potential, this phenomena, surprisingly, is not valid for the GFs and QNMs. With the proper graphics and tables, all outputs are depicted, tabulated, and interpreted.

hep-th↗

Fermionic greybody factors in Schwarzschild acoustic black holes

In Schwarzschild's acoustic black hole (SABH) spacetime, we investigate the wave dynamics for the fermions. To this end, we first take into account the Dirac equation in the SABH by employing a null tetrad in the Newman-Penrose (NP) formalism. Then, we consider the Dirac and Rarita Schwinger equations, respectively. The field equations are reduced to sets of radial and angular equations. By using the analytical solution of the angular equation set, we decouple the radial wave equations and obtain the one-dimensional Schrödinger like wave equations with their effective potentials. The obtained effective potentials are graphically depicted and analyzed. Finally, we investigate the fermionic greybody factors (GFs) radiated by the SABH spacetime. A thorough investigation is conducted into how the acoustic tuning parameter affects the GFs of the SABH spacetime. Both the semi-analytic WKB method and bounds for the GFs are used to produce the results, which are shown graphically and discussed.

hep-th↗

Non-perturbative correction to the Horava-Lifshitz black hole thermodynamics

In this paper, we consider non-perturbative quantum correction which appears as exponential term in the black hole entropy. We study consequence thermodynamics of the Hořava-Lifshitz black hole at quantum scales. We consider two cases of Kehagius-Sfetsos and Lu-Mei-Pop solutions and investigate black hole stability. We find that non-perturbative quantum correction yields to an instability at infinitesimal horizon radius of Kehagius-Sfetsos solution. On the other hand, non-perturbative quantum correction yields to the stability of Lu-Mei-Pop solution. Hence, we find that holographic dual of Lu-Mei-Pop black hole (in absence of non-perturbative quantum correction) is the interacting gas of point like particles, while it is Van der Waals fluid in presence of non-perturbative quantum correction.

hep-th↗

Gravitational Lensing in Kerr-Newman Anti de Sitter Spacetime

The method of Rindler and Ishak enables one to study how light is bent in the vicinity of a non-rotating and spherically symmetric gravitational lens. This method mainly aims to investigate the role of cosmological constant in the consequent path. In this paper, we use the extension of Rindler-Ishak method (RIM) in order to evaluate the deflection angle of null geodesics in the equatorial plane of Kerr-Newman anti de Sitter (KNAdS) spacetime. We then use astrophysical data to see the effect of rotation and charge on the bending angle of light for seven distinct stars and two black holes under the assumption of having a KNAdS background with a negative cosmological constant $Λ$.

gr-qc↗

Topical Review: Greybody Factors and Quasinormal Modes for Black Holes in Various Theories -- Fingerprints of Invisibles

We give a pedagogical introduction to black holes (BHs) greybody factors (GFs) and quasinormal modes (QNMs) and share the recent developments on those subjects. In this study, our primary focus will be on the bosonic and fermionic GFs and QNMs of various BH and brane geometries and reveal the fingerprints of the invisibles with the radiation spectra to be obtained by the WKB approximation and bounding the Bogoliubov coefficients (together with the Miller-Good transformation) methods. (*Due to the notification of arXiv "The Abstract field cannot be longer than 1,920 characters", the appeared Abstract is shortened. For the full Abstract, please download the Article.)

hep-th↗

Fermionic and Bosonic Greybody Factors as well as Quasinormal Modes for Charged Taub NUT Black Holes

The paper studies the spinorial wave equations, namely the Dirac and the Klein Gordon equations, as well as the greybody radiations and quasinormal modes (QNMs) of the charged Taub NUT black hole (CTNBH). To obtain fermionic greybody factors (GFs) and QNMs, we study the charged fermions by employing the Dirac equation. To this end, we use a null tetrad in the Newman-Penrose formalism. Then, we separate the Dirac equation into radial and angular sets. Using the obtained radial equations, we convert them into the typical one dimensional Schrödinger like wave equations with the aid of tortoise coordinate and derive the effective potentials. For bosonic GFs and QNMs, we study the Klein Gordon equation in the CTNBH geometry and obtain the radial equation. We then derive the effective potential and investigate the effect of NUT parameter on it. We show that while the fermionic QNMs and GFs individually increase with the increasing NUT parameter, the increase of bosonic GFs with increasing NUT parameter is overwhelmingly greater than that of the bosonic QNMs.

hep-th↗