Research Overview

Prof. Dr. Ali Övgün’s research is focused on understanding and constraining modified gravity theories using various properties of black holes and cosmological evolution. He has contributed to widely used analytical methods for calculating Hawking radiation, gravitational lensing, and shadow casts of black holes, wormholes, compact stars, and cosmological inflation.

◆ Research Areas & Selected Publications
Gravitational Lensing Black-Hole Shadows Quantum Gravity Quasinormal Modes Hawking Radiation Quantum Optics Josephson Effects Modified Gravity Nonlinear Electrodynamics Regular Black Holes Wormholes Particle Dynamics Black-Hole Thermodynamics Cosmology & Inflation Dark Matter & Astroparticle Physics
Publications are organized according to their primary scientific contribution. Only works with a final journal publication are included below. Click a research area to expand its selected publications.
1. Gravitational Lensing, Black-Hole Shadows & Optical Geometry
7 selected publications

Research on weak and strong gravitational lensing, the Gauss–Bonnet theorem, finite-distance corrections, optical geometry, photon spheres, black-hole shadows and Event Horizon Telescope 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
  • Radial Integral Reformulation of the Gauss-Bonnet Weak Deflection Angle at Finite Distance — Chinese J. Phys. 103, 1523–1535 (2026) · arXiv:2601.17059
  • 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 by Kerr-MOG Black Hole and Gauss–Bonnet theorem — Ann. Phys. 411, 167978 (2019) · arXiv:1806.06453
  • 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
7 selected publications

Research on 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
  • Quantum gravity effects on particle creation and evaporation in a non-commutative black hole via mass deformation — Int. J. Geom. Methods Mod. Phys. 23(10), 2550253 (2026) · arXiv:2409.03566
  • 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
8 selected publications

Research on 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 of Kerr-like black bounce spacetime — Mod. Phys. Lett. A (2026) · arXiv:2205.07530
  • 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
  • Quasinormal modes of dS and AdS Black Holes: Feedforward neural network method — Int. J. Geom. Methods Mod. Phys. 18(10), 2150154 (2021) · arXiv:1904.09509
4. Hawking Radiation, Quantum Optics & Horizon Physics
7 selected publications

Research at the interface of quantum optics, quantum field theory in curved spacetime, Hawking radiation, acceleration radiation 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
3 selected publications

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

  • 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
6 selected publications

Research on 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
6 selected publications

Research on 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
6 selected publications

Research on traversable wormholes, 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
4 selected publications

Research on 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
4 selected publications

Research on 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
5 selected publications

Research on nonlinear-electrodynamics cosmology, inflation, matter–antimatter asymmetry and gravitational effects in the early Universe.

  • 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
5 selected publications

Research connecting black-hole physics with dark-matter distributions, 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
❓ Fundamental Questions Under Investigation
□ Is it possible that the Big Bang could be replaced with a wormhole at the beginning of time?
□ Is it possible to create a traversable wormhole in modified gravity theories?
⚛️ How can quantum effects be included in black hole & wormhole thermodynamics?
□️ What happens at the event horizon edge or inside a Black Hole singularity?
□ Could Our Universe Be A Hologram? How many dimensions exist in the holographic universe?
□ Why is the universe expanding at an accelerating rate?
□ How are brain cell networks structure-wise similar to cosmic web universes?
□ Research Topics for M.Sc. & Ph.D. Students
□ Cosmology
Cosmological models with Nonlinear electrodynamics, Cosmological singularities, Inflation, and Accelerated expansion of the Universe.
□ Gravitational Lensing & Shadow Cast
Weak/Strong Gravitational Lensing, Light Deflection with Topological Defects and Gauss-Bonnet Theorem, Shadow of Black Holes/Wormholes, and Thin-accretion disks.
□ Wave Properties of BHs & WHs
Hawking Radiation, Quasinormal Modes of Black Holes, Greybody factors, and Quantum Singularities.
□ Black Hole Chemistry & Holography
Thermodynamics with Cosmological Constant (Λ), P-V Criticality, Phase Transitions, Super-entropic BHs, Van der Waals fluids, and Holographic Thermodynamics.
□ Wormhole Physics
Stability of Thin-shell Wormholes and Lorentzian Wormholes (WHs) in extended gravity backgrounds.
⚛️ Particle Properties & Geodesics
Geodesics and BSW effect of BHs/WHs, Particle Acceleration mechanisms by compact objects.
□ Compact Stars & Gravastars
Structure, thermodynamics, and stability of Gravastars, Quark Stars, and Neutron Stars.
□ Quantum Entanglement & Complexity
Quantum complexity inside black holes and Holographic Action Growth Rates.
□ Quantum Optics in Curved Spacetimes
Behavior and propagation of quantum optical signals near curved relativistic backgrounds.
□️ Modified Gravity Theories
Bumblebee Lorentz-violating gravity, Gauss-Bonnet gravity, f(R) gravity, and Symmergent gravity models.
□‍□ Thesis Supervisorships & Co-Supervisorships
PhD Supervisor — Yashmitha Kumaran
Thesis: Weak Deflection Angle via Gauss-Bonnet Theorem (Eastern Mediterranean University)
2018 – 2023
MSc Supervisor — Flora Babayeva
Thesis: Shadow Cast of The Schwarzschild-like Black Holes (EMU)
2020 – 2022
MSc Supervisor — Hamza Saber Zebari
Thesis: Newtonian Cosmology (EMU)
2018 – 2020
MSc Supervisor — Gabriel Wirdzelii Joseph
Thesis: Cosmology with Varying Physical Constants (EMU)
2018 – 2020
MSc Supervisor — Hüseyin Karyal
Thesis: Geodesics of Black Holes in Bumblebee Gravity Theory (EMU)
2018 – 2020
MSc Co-Supervisor — İlim İrfan Çimdiker
Project: Black Hole Shadow in Symmergent Gravity (Sabancı University, Supervisor: Prof. Dr. Durmuş Ali Demir)
2021
BSc Co-Supervisor — Mert Okyay
Publication: Nonlinear electrodynamics effects on black hole shadow, deflection angle, QNMs and greybody factors, JCAP 2022 (Miami University, USA)
2022
BSc Co-Supervisor — Ceren H. Bayraktar
Publication: Thermodynamics of regular black holes with cosmic strings, EPJ Plus 2018 (IZTECH, Supervisor: Prof. Dr. Durmuş Ali Demir)
2018
Student Research Projects
Student Research Project — Cem Kalkanlı
Project: Black Hole Physics (Istanbul Technical University, Turkey)
2025
Student Research Project — Sıla Karip
Project: Beyond Standard FLRW: How a Time-Dependent Conformal Factor Alters Cosmic Expansion (Eastern Mediterranean University)
2026
Student Research Project — Kadir Akıcı
Project: Relativistic Light-Sail Propulsion to Proxima Centauri (Eastern Mediterranean University)
2026