arXiv subjects

S. Saoud

Publications and source records attributed to S. Saoud.

4 recordsLinked to original sources

arXiv2026

Optics and Thermodynamics of Charged BTZ Black Holes with Exotic Matter Sources

We study a modified charged BTZ black hole in $(2+1)$--dimensional anti-de Sitter spacetime, where the standard geometry is surrounded by quintessence-like anisotropic matter and a cloud of strings. The corresponding metric function incorporates the effects of the electric charge and the two matter sources. The optical analysis reveals that their combined influence gives rise to a stable circular photon orbit, leading to distinctive modifications of photon dynamics and the associated energy emission. The thermodynamic analysis in a finite cavity further shows that the electric charge and exotic matter sources significantly affect the local thermal stability and phase structure of the black hole. The combined effects of these matter sources give rise to a stable photon sphere and novel thermodynamic behavior absent in the standard charged BTZ solution.

hep-th↗

arXiv2026

A Swampland-modified Hod bound for charged black holes with exotic matter

In this paper, we study the quasinormal modes (QNMs) of a charged black hole in the presence of both quintessence and a cloud of strings using the Pade-averaged higher-order WKB approximation method. We investigate the effect of the quintessence parameter $\alpha$ and the cloud of strings parameter $\lambda$ on the stability as well as the oscillation frequency of perturbations. The validity of Hod's conjecture, which relates quasinormal frequencies to the black hole temperature, is tested throughout the physically allowed parameter space. Our results show that both the effective potential and the decay rate of perturbations depend on the values of $\alpha$ and $\lambda$, leading to either enhancement or suppression of the conditions required to satisfy Hod's bound. Furthermore, we discuss how these parameters modify the black hole shadow and the corresponding energy emission rate, revealing correlations with observable signatures. Finally, we establish a connection with the Swampland Distance Conjecture by expressing the Hawking temperature in terms of the scalar field excursion. Our analysis leads to a modified Hod bound and identifies a region of parameter space in which both the modified Hod bound and the Swampland constraints are simultaneously satisfied, ensuring consistency between black hole thermodynamics, observational properties, and quantum gravity constraints.

hep-th↗

arXiv2025

Compactified 2HDM under the Non-SUSY AdS instability conjecture

We investigate how extra-dimensional dynamics influence Higgs-sector phenomenology by compactifying a Two-Higgs-Doublet Model (2HDM) coupled to 4D gravity on a circle $S^1$. The resulting effective potential includes tree-level 2HDM interactions, one-loop Coleman--Weinberg corrections from the Kaluza--Klein towers, and an effective radion stabilization contribution inspired by the broader modulus-stabilization literature. We derive the corresponding 3D effective action and show that, for the observed Higgs mass $m_h=125\,\mathrm{GeV}$, the compactified potential admits a stabilized configuration with near-zero vacuum energy. By imposing the non-supersymmetric AdS instability conjecture as a quantum-gravity consistency requirement, we obtain a constraint within our numerical setup on the heavy Higgs sector, finding that the additional scalar states must satisfy approximately $M_H \gtrsim 680\,\mathrm{GeV}$ in order to avoid perturbatively stable non-supersymmetric AdS$_3$ minima. Our results demonstrate how Swampland-inspired constraints can yield phenomenologically relevant predictions for extended Higgs sectors.

hep-ph↗

arXiv2025

Swampland bound on quintessential inflation in IDM

We study a quintessential inflation scenario based on the Inert Doublet Model (IDM) coupled to a quintessence field via an exponential potential $V_0e^{-\beta\phi/M_p}$. Using a conformal transformation from the Jordan frame to the Einstein frame, we derive an effective Starobinsky-type potential modulated by an exponential factor that naturally unifies the inflationary epoch with the late-time accelerated expansion of the Universe. We analyze the resulting two-field dynamics, compute the slow-roll parameters, the primordial perturbation spectrum, as well as the inflationary observables $n_s$ and $r$, and then confront the predictions with the latest $Planck$ and $BICEP/Keck$ data. We find amongst others that the quintessence inflaton coupling must remain extremely weak, in the order of $\beta \lesssim 4\times10^{-3}$, to satisfy current $CMB$ data, whereas swampland dS conjecture favors a step potential with $\beta\sim\mathcal{O}(1)$, signaling a significant tension between quantum gravity consistency and cosmological viability. We conclude by discussing possible extensions and stabilization mechanisms that could help reconcile the inflationary predictions with swampland constraints.

hep-ph↗