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Prof. Dr. Ali Övgün

Research


Research Areas, Selected Publications

We conduct theoretical research at the interface of gravitation, astrophysics, quantum theory and cosmology. Research focuses on black-hole physics, quantum-gravity phenomenology, gravitational lensing, compact objects, modified gravity, nonlinear electrodynamics and observational tests of fundamental physics.

Bibliographic format: Title - Journal Volume/Issue, Article/Page (Year) - arXiv identifier. Published journal details are used when available; otherwise the item is marked Preprint or Accepted/In press.

Research Areas & Selected Publications

1. Gravitational Lensing, Black-Hole Shadows & Optical Geometry

Weak and strong gravitational lensing, Gauss-Bonnet methods, finite-distance corrections, optical geometry, photon spheres, black-hole shadows and EHT phenomenology.

·       Reference-renormalized curvature-primitive Gauss-Bonnet formalism for finite-distance weak gravitational lensing in static spherical spacetimes - Phys. Rev. D 113, 104037 (2026) - arXiv:2604.16807

·       Boundary-only weak deflection angles from isothermal optical geometry - Class. Quantum Grav. 43(8), 085011 (2026) - arXiv:2601.06864

·  Gravitational Black Hole Shadow Spectroscopy - Phys. Rev. D 112, 124072 (2025) - arXiv:2509.05594

·       General Approach on Shadow Radius and Photon Spheres in Asymptotically Flat Spacetimes and the Impact of Mass-Dependent Variations - Phys. Lett. B 854, 138758 (2024) - arXiv:2404.18536

·       Weak gravitational lensing of regular black holes with cosmic strings using the Gauss-Bonnet theorem - Phys. Rev. D 99, 104075 (2019) - arXiv:1902.04411

2. Quantum Gravity Phenomenology & Noncommutative Geometry

Phenomenological signatures of quantum gravity, uncertainty principles, minimal length, effective quantum gravity and noncommutative spacetime.

·       Probing Quantum Gravity in Stellar Spacetimes: Phenomenological Insights - Phys. Dark Universe 52, 102243 (2026) - arXiv:2505.18997

·       Spacetime-curvature induced uncertainty principle: Linking the large-structure global effects to the local black hole physics - Phys. Dark Universe 47, 101817 (2025) - arXiv:2312.00409

·       Absorption, Scattering, Geodesics, Shadows and Lensing Phenomena of Black Holes in Effective Quantum Gravity - Phys. Dark Universe 47, 101815 (2025) - arXiv:2410.08246

·       Effects of non-commutative geometry on black hole properties - Phys. Dark Universe 46, 101630 (2024) - arXiv:2406.12015

·       Traces of quantum gravitational correction at third-order curvature through the black hole shadow and particle deflection at the weak field limit - Phys. Dark Universe 46, 101597 (2024) - arXiv:2406.18292

·       Constraints via the Event Horizon Telescope for Black Hole Solutions with Dark Matter under the Generalized Uncertainty Principle Minimal Length Scale Effect - Ann. Phys. (Berlin) 536(4), 2300390 (2024) - arXiv:2309.07442

3. Quasinormal Modes, Ringdown & Greybody Factors

Black-hole perturbations, gravitational ringdown, quasinormal-mode spectroscopy, stability and transmission/greybody factors.

·       Ringdown of a black hole sourced by a Burkert-density effective anisotropic source - Phys. Rev. D 114, 023051 (2026) - arXiv:2511.07858

·       Quasinormal Mode Spectroscopy via Horizon-Brightened Quantum Optics - Eur. Phys. J. C 86, 293 (2026) - arXiv:2511.07488

·       Signatures of a de Sitter-core black hole in ringing, transmission and optical appearance - Phys. Lett. B 879, 140606 (2026) - arXiv:2412.05072

·       Quasinormal Modes and Greybody Factors of Charged Symmergent Black Hole - Phys. Dark Universe 47, 101796 (2025) - arXiv:2410.00691

·       Shadow and quasinormal modes of the rotating Einstein-Euler-Heisenberg black holes - Phys. Dark Universe 48, 101886 (2025) - arXiv:2406.18300

·       Probing hairy black holes caused by gravitational decoupling using quasinormal modes and greybody bounds - Phys. Rev. D 107, 064042 (2023) - arXiv:2203.11551

4. Hawking Radiation, Quantum Optics & Horizon Physics

Quantum optics and quantum field theory in curved spacetime, Hawking radiation, acceleration radiation, detector physics and horizon thermodynamics.

·       Horizon brightened acceleration radiation from massive vector fields - Phys. Rev. D 113, 084040 (2026) - arXiv:2512.08598

·       Horizon-Brightened Acceleration Radiation and Optical Signatures of Generic Regular Black Holes from Nonlinear Electrodynamics - Eur. Phys. J. C 86, 631 (2026) - arXiv:2602.15077

·       Acceleration Radiation of Freely Falling Atoms: Nonlinear Electrodynamic Effects - Phys. Dark Universe 52, 102279 (2026) - arXiv:2512.21387

·       Acceleration radiation from vibrating atoms in Schwarzschild spacetime - Chinese J. Phys. 103, 89-113 (2026) - arXiv:2510.11761

·       HBAR entropy of Infalling Atoms into a GUP-corrected Schwarzschild Black Hole and equivalence principle - Phys. Lett. A 568, 131201 (2026) - arXiv:2506.10621

·       Hawking Radiation via Gauss-Bonnet Theorem - Ann. Phys. 413, 168071 (2020) - arXiv:1902.04465

·       The Bekenstein-Hawking Corpuscular Cascading from the Backreacted Black Hole - Adv. High Energy Phys. 2017, Article ID 1573904 (2017) - arXiv:1609.07804

5. Gravitational Josephson Effects & Macroscopic Quantum Phenomena

Josephson transport, superconducting quantum phenomena in curved spacetime and gravitationally modified quantum phase evolution.

·       Near extremal RN-AdS control of holographic Josephson transport - Preprint (2026) - arXiv:2606.06558

·       Josephson Effects in Slowly Rotating Spacetimes - Eur. Phys. J. C 86, 595 (2026) - arXiv:2603.07553

·       Josephson's effect in the Schwarzschild background - JHEP 02 (2026) 006 - arXiv:2510.26048

·       The Sound of an Orbit: A Quantum Spectrum at the ISCO - Fortschr. Phys. (2025), e70048 - arXiv:2507.14254

6. Modified Gravity, Symmergent Gravity & Lorentz-Symmetry Breaking

Lorentz violation, Bumblebee and Kalb-Ramond gravity, symmergent gravity and other extensions of General Relativity.

·       Lorentz-violating modifications to particle dynamics, thermodynamics and vacuum energy in bumblebee gravity - Eur. Phys. J. Plus 141, 843 (2026) - arXiv:2601.07102

·       Charged black holes in Kalb-Ramond gravity: Weak deflection angle, shadow cast, quasinormal modes and neutrino annihilation - Phys. Dark Universe 49, 102029 (2025) - arXiv:2505.17947

·       Weak Gravitational Lensing in Ricci-Coupled Kalb-Ramond Bumblebee Gravity: Global Monopole and Axion-Plasmon Medium Effects - Phys. Dark Universe 48, 101905 (2025) - arXiv:2504.07130

·       Asymptotically-Flat Black Hole Solutions in Symmergent Gravity - Fortschr. Phys. 72, 2300138 (2024) - arXiv:2403.02373

·       Constraints on charged Symmergent black hole from shadow and lensing - Class. Quantum Grav. 40, 195003 (2023) - arXiv:2308.08415

·       Schwarzschild-like black hole with a topological defect in bumblebee gravity - Ann. Phys. 436, 168721 (2022) - arXiv:2012.02611

7. Nonlinear Electrodynamics & Regular Black Holes

Regular black holes, nonsingular cores, nonlinear electromagnetic fields and black-hole formation from physically motivated matter.

·       Optical and orbital characterization of spherically symmetric static black holes of self-gravitating new nonlinear electrodynamics model - Phys. Rev. D 114, 024032 (2026) - arXiv:2603.10097

·       Regular Black Hole Models in the Transition from Baryonic Matter to Quark Matter - JCAP 06 (2025) 051 - arXiv:2504.07561

·       Formation of regular black hole from baryonic matter - Chinese Phys. C 49(11), 115103 (2025) - arXiv:2502.00521

·       Exact Regular Black Hole Solutions with de Sitter Cores and Hagedorn Fluid - Eur. Phys. J. C 85, 1243 (2025) - arXiv:2408.02699

·       New Black Hole Solutions of Second and First Order Formulations of Nonlinear Electrodynamics - Phys. Rev. D 111, 084061 (2025) - arXiv:2412.20989

·       Shadow and greybody bounding of a regular scale-dependent black hole solution - Ann. Phys. 463, 169625 (2024) - arXiv:2402.14190

8. Wormholes, Black Bounces & Exotic Compact Objects

Traversable and thin-shell wormholes, black bounces, gravastars and black-hole mimickers.

·       Modified particle dynamics and thermodynamics in a traversable wormhole in bumblebee gravity - Class. Quantum Grav. 42, 032001 (2025) - arXiv:2409.17351

·       Traversable Wormholes in Minimally Geometrical Deformed Trace-Free Gravity using Gravitational Decoupling - Ann. Phys. 462, 169614 (2024) - arXiv:2401.16814

·       Rotating black hole mimicker surrounded by the string cloud - Phys. Rev. D 109, 024002 (2024) - arXiv:2307.09344

·       Weak deflection angle of black-bounce traversable wormholes using Gauss-Bonnet theorem in the dark matter medium - Turk. J. Phys. 44, 465-471 (2020) - arXiv:2011.04423

·       Exact traversable wormhole solution in bumblebee gravity - Phys. Rev. D 99, 024042 (2019) - arXiv:1804.09911

·       Thin-shell wormholes from the regular Hayward black hole - Eur. Phys. J. C 74, 2796 (2014) - arXiv:1312.6665

9. Particle Dynamics, Accretion, ISCOs & QPOs

Particle motion, spinning particles, periodic orbits, accretion disks, ISCOs, QPOs and relativistic orbital observables.

·       Equatorial periodic orbits and gravitational wave signatures in Euler-Heisenberg black holes surrounded by perfect fluid dark matter - JCAP 07 (2026) 087 - arXiv:2604.11866

·       Semi-Analytic Trajectory Analysis of Light in Generic Static Spacetimes - Nucl. Phys. B 1029, 117557 (2026) - arXiv:2507.16512

·       Geodesics, accretion disk, gravitational lensing, time delay, and effects on neutrinos induced by a non-commutative black hole - JCAP 06 (2025) 062 - arXiv:2412.08369

·       Thin accretion disk images of the black hole in symmergent gravity - Class. Quantum Grav. 40, 184001 (2023) - arXiv:2308.03947

10. Black-Hole Thermodynamics & Phase Structure

Black-hole thermodynamics, critical phenomena, phase transitions, entropy corrections and extended thermodynamic phase space.

·       Thermodynamics and logarithmic corrections of symmergent black holes - Results Phys. 46, 106300 (2023) - arXiv:2302.12875

·       Holographic Thermodynamics of Accelerating Black Holes - Phys. Rev. D 98, 104038 (2018) - arXiv:1805.02687

·       Novel nonlinear electrodynamics black hole and related phenomena in the extended thermodynamics - Eur. Phys. J. C 78, 840 (2018) - arXiv:1807.10447

·       P-v criticality of a specific black hole in f(R) gravity coupled with Yang-Mills field - Adv. High Energy Phys. 2018, Article ID 8153721 (2018) - arXiv:1801.09615

11. Cosmology, Inflation & Early-Universe Physics

Nonlinear-electrodynamics cosmology, inflation, matter-antimatter asymmetry, QCD matter and gravitational effects in the early Universe.

·       Can finite-density QCD matter support a regular black hole core? - Accepted in JCAP (2026) - arXiv:2605.27170

·       Cosmology with variable G and nonlinear electrodynamics - Indian J. Phys. 96, 1861-1866 (2022) - arXiv:2104.11066

·       Matter-antimatter asymmetry induced by non-linear electrodynamics - Class. Quantum Grav. 38, 135019 (2021) - arXiv:2105.07695

·       Inflation from a nonlinear magnetic monopole field nonminimally coupled to curvature - JCAP 06 (2018) 003 - arXiv:1803.11358

·       Falsifying cosmological models based on a non-linear electrodynamics - Eur. Phys. J. C 78, 462 (2018) - arXiv:1709.09794

·       Inflation and Acceleration of the Universe by Nonlinear Magnetic Monopole Fields - Eur. Phys. J. C 77, 105 (2017) - arXiv:1604.01837

12. Dark Matter, Astroparticle Physics & Multi-Messenger Tests

Black holes in dark-matter environments, EHT observations, gravitational waves, neutrinos and multi-messenger constraints.

·       Black hole in the Dekel-Zhao dark matter profile - Phys. Lett. B 864, 139398 (2025) - arXiv:2501.12559

·       Black hole surrounded by the pseudo-isothermal dark matter halo - Eur. Phys. J. C 84, 63 (2024) - arXiv:2308.05544

·       Black hole in quantum wave dark matter - Fortschr. Phys. 71, 2200164 (2023) - arXiv:2210.00523

·       Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A* - Class. Quantum Grav. 40, 165007 (2023) - arXiv:2205.07787

·       Formation of Wormholes by Dark Matter in the Galaxy Dragonfly 44 - Can. J. Phys. 97(3), 241-247 (2019) - arXiv:1806.01135