arXiv subjects

Yusuf Sucu

Publications and source records attributed to Yusuf Sucu.

At least 19 recordsLinked to original sources

arXiv2026

Quantum-Corrected Thermodynamics, Dirac Perturbations, Geodesic Structure, and Topological Phases of Black Holes with Non-Minimal Logarithmic Coupling

We study the thermodynamic and dynamical properties of static, spherically symmetric BHs in Einstein-Maxwell theory modified by a non-minimal $\ln(R)F^{2}$ coupling. The Hawking temperature follows from the Hamilton-Jacobi form of the fermionic tunnelling method for spin-$\tfrac12$ particles, and it carries scale-dependent logarithmic corrections. We then analyze the propagation of massless Dirac fields, compute the quasinormal-mode (QNM) spectrum with the third-order WKB approximation, and read off a quality factor whose balance between oscillation and damping depends on the logarithmic coupling in a mode-dependent way. Moving outward from the horizon, we work out the transmission of the fermionic field and its Hawking emission, and we solve the null and timelike geodesic problems to obtain the photon sphere, the shadow radius, the innermost stable circular orbit (ISCO), the associated zoom-whirl bound orbits, and the orbital and epicyclic frequencies that set the twin-peak quasiperiodic-oscillation (QPO) ratio. A photon-sphere reading of the eikonal QNM frequencies ties the geodesic sector back to the field perturbations. On the thermodynamic side, we build the phase space with quantum-geometric corrections through the Barrow entropy, and we characterize the global phase structure with the topological method, where the winding numbers of the off-shell free energy are governed by the interplay of the fractal Barrow deformation, the electric charge, and the logarithmic coupling. We find that the effective pressure vanishes exactly on the topological defect line, which links the pressure sign to the local stability of each branch.

gr-qc↗

arXiv2025

Quantum-Corrected Thermodynamics and Plasma Lensing in Non-Minimally Coupled Symmetric Teleparallel Black Holes

We investigate the thermodynamic and optical signatures of electrically charged black holes (BHs) in symmetric teleparallel gravity (STPG) with non-minimal electromagnetic coupling, incorporating quantum corrections and plasma dispersion effects. The BH solution, characterized by a coupling parameter $k$, generalizes the Reissner-Nordström spacetime through power-law modifications to electromagnetic terms in the metric function. We implement exponential corrections to the Bekenstein-Hawking entropy of the form $S = S_0 + e^{-S_0}$ and derive quantum-corrected expressions for fundamental thermodynamic quantities including internal energy, Helmholtz and Gibbs free energies, pressure, enthalpy, and heat capacity. Our analysis reveals rich phase transition structures with second-order transitions occurring at critical horizon radii for specific coupling values, demonstrating enhanced thermodynamic instability under strong non-minimal coupling effects. The quantum-corrected Joule-Thomson expansion analysis identifies distinct cooling and heating regimes separated by inversion points that shift systematically with the coupling parameter $k$. We analyze the efficiency of heat engines operating in Carnot cycles, finding that electromagnetic charge enhances thermodynamic performance with efficiency values approaching 99\% for optimal configurations in this geometry. Using the Gauss-Bonnet theorem, we derive analytical expressions for gravitational deflection angles in both vacuum and plasma environments, revealing how non-minimal coupling and plasma dispersion create frequency-dependent lensing signatures that differ substantially from general relativity predictions.

gr-qc↗

arXiv2020

Quantum gravity correction to Hawking radiation of the 2+1 dimensional wormhole

We carry out the Hawking temperature of a (2+1) dimensional circularly symmetric traversable wormhole in the framework of the generalized uncertainty principle (GUP). Firstly, we introduce the modified Klein-Gordon equation of the spin-0 particle, the modified Dirac equation of the spin-1/2 particle, and the modified vector boson equation of the spin-1 particle in the wormhole background, respectively. Given these equations under the Hamilton-Jacobi approach, we analyze the GUP effect on the tunneling probability of these particles near the trapping horizon, and subsequently, on the Hawking temperature of the wormhole. Furthermore, we have found that the modified Hawking temperature of the wormhole is determined by both wormhole's and tunneling particle's properties and indicated that the wormhole has a positive temperature similar to that of a physical system. This case indicates that the wormhole may be supported by ordinary (non-exotic) matter. In addition, we calculate the Unruh-Verlinde temperature of the wormhole by using Kodama vectors instead of time-like Killing vectors, and observe that it equals to the standard Hawking temperature of the wormhole.

hep-th↗

arXiv2019

Exact annihilation energy and proper decay time solution of a para-positronium system

Para positronium composed by an electron-antielectron pair is an unstable system decaying into two high energetic gamma photons via self annihilation process, due to the conservation of the charge conjugation parity in electromagnetically interacting systems. Therefore, the spectrum covering all fundamental properties of the para-positronium system includes an imaginary part corresponding to the proper decay time besides the real parts corresponding to the total annihilation energy and binding energy, simultaneously. The para-positronium can be regarded as relativistic two body system in which there exist a Coulomb interaction force between the oppositely charged particles. Because of the annihilation condition, ($l=0$), and total spin of the system, ($S=0$), the problem is solved in 1+1 dimensional spacetime background by using fully covariant relativistic two body equation, without any approximation. Adopting the obtained spectra to an electron-antielectron pair we find total annihilation energy, binding energy and proper decay time of the para-positronium system. Since the obtained spectra shows the fascinating properties of the system, our findings can shed light to medical monitoring processes, positron annihilation spectroscopy in any system and gamma-ray laser studies.

quant-ph↗

arXiv2019

Particle Production via Dirac Dipole Moments in the Magnetized and Non-magnetized Exponentially Expanding Universe

In the present paper, we solve the Dirac equation in the 2+1 dimensional exponentially expanding magnetized by uniform magnetic field and non-magnetized universes, separately. Asymptotic behaviors of the solutions are determined. Using these results we discuss the current of a Dirac particle to discuss the polarization densities and the magnetization density in the context of Gordon decomposition method. In this work we also calculate the total polarization and magnetization, to investigate that the magnetic field how can effect on the particle production. Furthermore, the electric and the magnetic dipole moments calculated, and based on these we have discussed the effects of the dipole moments on the charge distribution of the universe and its conductivity for both the early and the future time epoch in the presence/absence a constant magnetic field and exponentially expanding spacetime.

hep-th↗

arXiv2019

Annihilation energy and decay time of an ortho-Positronium

We approach to the ortho-positronium (o-Ps) as a relativistic two-body problem in $2+1$ dimensions in which o-Ps is composed of two-oppositely charged particles interacting via an attractive Coulomb force. In addition to separation of center of mass and relative coordinates, mapping the background into the polar space-time gives possibility of construction of possible spin eigen-states of o-Ps. This approach makes the energy spectrum complex in order to describe o-Ps that can decay. From the complex energy expression, we find the annihilation energy, binding energy and the life-time of o-Ps, in S state.

hep-ph↗

arXiv2019

A New Approach to Compute the Dipole Moments of a Dirac Electron

We present an approach to compute the electric and magnetic dipole moments of an electron by using polarization and magnetization parts of the Dirac current. We show that these dipole moment expressions obtained by our approach in this study are in agreement with the current experimental results in the literature. Also, we observe that a magnetic field plays an important role in the magnitude of the electrical dipole moment of the electron.

quant-ph↗

arXiv2019

Photon in the Earth-ionosphere cavity: Schumann resonances

We study a quantum analogy of Schumann resonances by solving massless and massive spin-1 particle equations derived from the Zitterbewegung model in an annular cavity background with poorly conducting walls. We also show that the massless case and the massive case in the $m_0^2 \rightarrow 0$ limit are compatible with Maxwell's electromagnetic theory. Furthermore, from the massive case, we predict an upper limit for the mass of the photon of 1.3x$10^{-50}$kg. The bound on the mass of the photon is compatible with the current limit in the literature.

hep-ph↗

arXiv2018

Quantum gravity effect on the Hawking radiation of charged rotating BTZ black hole

In this study, the quantum gravity effect on the tunnelling radiation of charged massive spin-0 scalar particle from 2+1 dimensional charged rotating Banados-Teitelboim-Zanelli (BTZ) black hole is looked into by using the Hamilton-Jacobi approach. For this, we calculate the modified Hawking temperature of the black hole by using the modified Klein-Gordon equation based on the Generalized Uncertainty Principle (GUP), and we noticed that the modified Hawking temperature of the black hole depends not only on the black hole properties, but also on the angular momentum, energy, charge and mass of the tunnelling scalar particle. Using the modified Hawking temperature, we discussed the stability of the black hole in the context of the modified heat capacity, and observed that it might undergo both first and second-type phase transitions in the presence of the quantum gravity effect, but just a first-type transition in the absence of the quantum gravity effect. Furthermore, we investigated the modified Hawking temperature of the black hole by using the tunnelling processes of the charged massive Dirac and vector boson particles. We observed that scalar, Dirac and vector particles are tunnelled from the black hole completely differently from each other in the presence of the quantum gravity effect.

gr-qc↗

arXiv2018

Exact solution of an exciton energy for a monolayer medium

We present exact solutions of an energy spectrum of 2-interacting particles in which they seem to be relativistic fermions in 2+1 space-time dimensions. The 2x2 spinor equations of 2-interacting fermions through general central potential were separated covariantly into the relative and center of mass coordinates. First of all, the coupled first order differential equations depending on radial coordinate were derived from 2x2 spinor equations. Then, a second order radial differential equation was obtained and solved for Coulomb interaction potential. We apply our solutions to exciton phenomena for a free-standing monolayer medium. Since we regard exciton as isolated 2-interacting fermions in our model, any other external effect such as substrate was eliminated. Our results show that the obtained binding energies in our model are in agreement with the literature. Moreover, the decay time of an exciton was found out spontaneously in our calculations.

cond-mat.mes-hall↗

arXiv2018

The GUP effect on tunnelling of massive vector bosons from the 2+1 dimensional black hole

In this study, the Generalized Uncertainty Principle (GUP) effect on the Hawking radiation formed by tunneling of a massive vector boson particle from the $2+1$ dimensional New-type Black Hole was investigated. We used modified massive vector boson equation based on the GUP. Then, the Hamilton-Jacobi quantum tunneling approach was used to work out the tunneling probability of the massive vector boson particle and, Hawking temperature of the black hole. Due to the GUP effect, the modified Hawking temperature was found to depend on the black hole properties, the AdS$_{3}$ radius, and on the energy, mass and total angular momentum of the tunneling massive vector boson. In the light of these results, we also observed that modified Hawking temperature increases by the total angular momentum the particle while it decreases by the energy and mass of the particle, and the graviton mass. Also, in the context of the GUP, we see that the Hawking temperature due to the tunnelling massive vector boson is completely different from both that of the spin-0 scalar and the spin-1/2 Dirac particles obtained in the previous study. We also calculate the heat capacity of the black hole using the modified Hawking temperature and then discuss influence of the GUP on the stability of the black hole.

gr-qc↗

arXiv2017

Quantum Gravity Effect on the Tunneling Particles from 2+1 dimensional New-type Black Hole

We investigate the Generalized Uncertainty Principle (GUP) effect on the Hawking temperature for the 2+1 dimensional New-type black hole by using the quantum tunneling method for both the spin-1/2 Dirac and the spin-0 scalar particles. In computation of the GUP correction for the Hawking temperature of the black hole, we modified Dirac and Klein-Gordon equations. We observed that the modified Hawking temperature of the black hole depends not only on the black hole properties, but also on the graviton mass and the intrinsic properties of the tunneling particle, such as total angular momentum, energy and mass. Also, we see that the Hawking temperature was found to be probed by these particles in different manners. The modified Hawking temperature for the scalar particle seems to be lower compared to its standard Hawking temperature. Also, we find that the modified Hawking temperature of the black hole caused by Dirac particle's tunnelling rised by the total angular momentum of the particle. It is diminishable by the energy and mass of the particle and graviton mass as well. These intrinsic properties of the particle, except total angular momentum for the Dirac particle, and graviton mass may cause screening for the black hole radiation.

gr-qc↗

arXiv2017

Cosmological Solutions in 2+1 Dimensional New Massive Gravity in the presence of the Dirac field

In this paper, we consider $2+1$ dimensional gravitational theory including a Dirac field that is minimally coupled to New Massive Gravity. We investigate cosmological solutions of the field equations by using the self-interaction potential form obtained by the existence of Noether symmetry. In this context, we obtain cosmological solutions that corresponds to inflationary as well as the oscillationary epochs of the universe. Moreover, we have seen that the Dirac field behaves like a dark energy in these epochs of the universe.

gr-qc↗

arXiv2017

The GUP effect on Hawking Radiation of the 2+1 dimensional Black Hole

We investigate the Generalized Uncertainty Principle (GUP) effect on the Hawking radiation of the 2+1 dimensional Martinez-Zanelli black hole by using the Hamilton-Jacobi method. In this connection, we discuss the tunnelling probabilities and Hawking temperature of the spin-1/2 and spin-0 particles for the black hole. Therefore, we use the modified Klein-Gordon and Dirac equations based on the GUP. Then, we observe that the Hawking temperature of the scalar and Dirac particles depend on not only the black hole properties, but also the properties of the tunnelling particle, such as angular momentum, energy and mass. And, in this situation, we see that the tunnellig probability and the Hawking radiation of the Dirac particle is different from that of the scalar particle.

gr-qc↗

arXiv2017

Relativistic quantum mechanical spin-1 wave equation in 2+1 dimensional spacetime

In this study, we introduce a relativistic quantum mechanical wave equation of the spin-1 particle as an excited state of the zitterbewegung and show that it is consistent with the 2+1 dimensional Proca theory. At the same time, we see that in the rest frame this equation has two eigenstates, particle and antiparticle states or negative and positive energy eigenstates, respectively, and satisfy $SO(2,1)$ spin algebra. As practical applications, we derive the exact solutions of the equation in the presence of a constant magnetic field and a curved spacetime. From these solutions, we find Noether charge by integrating the constructed spin-1 particle current on hyper surface and discuss pair production from the charge. And, we see that the discussion on \ the Noether charge is useful tool for undersdantding the pair production phenomenon because the charge is derived from a probabilistic particle current.

gr-qc↗

arXiv2017

Dirac field as a source of the inflation in 2+1 dimensional Teleparallel gravity

In this paper, we study early-time inflation and late-time acceleration of the universe by non-minimally coupling the Dirac field with torsion in the spatially flat Friedman-Robertson-Walker (FRW) cosmological model background. The results obtained by the Noether symmetry approach with and without a gauge term are compared. Additionally, we compare these results with that of the 3+1 dimensional teleparallel gravity under Noether symmetry approach. And we see that the study explains early-time inflation and late-time acceleration of the universe.

gr-qc↗

arXiv2015

Noether gauge symmetry of Dirac field in $2+1$ dimensional gravity

In this paper, we consider a gravitational theory including a Dirac field that is non-minimal coupled to gravity in $2+1$ dimensions. Noether gauge symmetry approach can be used to fix the form of coupling function $F(Ψ)$ and the potential $V(Ψ)$ of the Dirac field and to obtain a constant of motion for the dynamical equations. In the context of $2+1$ dimensions gravity, we investigate cosmological solutions of the field equations using these forms obtained by the existent of Noether gauge symmetry. In this picture, it is shown that for the non-minimal coupling case, the cosmological solutions indicate both an early-time inflation and late-time acceleration for the universe.

gr-qc↗

arXiv2014

Hawking Radiation of Topological Massive Warped-AdS3 Black Hole Families

We investigate the Dirac particles tunnelling as a radiation of Warped AdS$_{3}$ black hole family in Topological Massive Gravity. Using the Hamilton-Jacobi method, we discuss tunnelling probability and Hawking temperature of the spin-1/2 particles for the black hole and its extremal cases. We observe that the Hawking temperature of the non-extremal black hole higher than the extremal black hole when $ω<\frac{2\ r_{0}}{3}$, because the non-extremal black hole become unstable in this case.

gr-qc↗