Physics of the Dark Universe最新文献

{"title":"Line-of-sight acceleration as a test of the Galactic Yukawa potential","authors":"Felipe A. da Silva Barbosa ,&nbsp;Luca Amendola ,&nbsp;Davi C. Rodrigues ,&nbsp;Roberto Capuzzo-Dolcetta","doi":"10.1016/j.dark.2025.102087","DOIUrl":"10.1016/j.dark.2025.102087","url":null,"abstract":"<div><div>We forecast the impact of direct radial acceleration measurements, based on two redshift measurements of the same target one decade apart, on constraining the Yukawa correction to the Newtonian potential in the Milky Way. The Galaxy’s matter distribution is modeled as the sum of a spherical bulge, a spherical dark matter halo, and two axially symmetric disks. Considering a sample of 165 Milky Way globular clusters, we find that the precision of next-generation spectrographs (<span><math><mo>∼</mo></math></span> 10 cm s⁻¹) is not sufficient to provide competitive constraints compared to rotation curve data using the same baryonic matter distribution. The latter sample only becomes competitive for a precision better than 0.6 cm s⁻¹. On the other hand, we find that adopting a population of <span><math><mrow><mn>1</mn><mo>.</mo><mn>3</mn><mspace></mspace><mo>×</mo><mspace></mspace><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span> RR Lyrae stars as targets, a precision of <span><math><mo>∼</mo></math></span> 10 cm s⁻¹ can achieve constraints on the Yukawa parameters as strong as with the rotation curves.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102087"},"PeriodicalIF":6.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling gravastar structure admitting Kuchowicz spacetime in Rastall gravity theory","authors":"Tayyab Naseer ,&nbsp;M. Sharif ,&nbsp;Areej Tabassum","doi":"10.1016/j.dark.2025.102088","DOIUrl":"10.1016/j.dark.2025.102088","url":null,"abstract":"<div><div>This paper investigates the gravastar model as a potential alternative to black holes, utilizing the Kuchowicz metric in the context of Rastall gravity. The model comprises three distinct regions: an interior with positive energy density and negative pressure, a thin intermediate shell made of ultra-relativistic stiff fluid, and an exterior vacuum. The negative pressure within the interior generates an outward force exerted on the shell, fulfilling the Zel’dovich criterion. This configuration eliminates the central singularity and replaces the event horizon with the shell. We then derive the radial metric functions for both the inner and thin region, yielding a non-singular solution. Furthermore, we examine the physical properties of the shell, such as its energy, proper length, entropy, equation of state parameter, gravitational redshift and adiabatic index, across a range of Rastall parameter values. We conclude that the resulting gravastar model offers a promising solution to the singularity problem of conventional black holes within the context of this non-conservative theory.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102088"},"PeriodicalIF":6.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bardeen thin-shell wormholes surrounded by fluid of strings","authors":"Arfa Waseem ,&nbsp;A. Eid ,&nbsp;Faisal Javed ,&nbsp;G. Mustafa","doi":"10.1016/j.dark.2025.102084","DOIUrl":"10.1016/j.dark.2025.102084","url":null,"abstract":"<div><div>This study investigates the construction and stability of thin-shell wormholes formed by gluing two identical forms of Bardeen-AdS black holes, surrounded by a fluid of strings, within the framework of nonlinear electrodynamics. Using the cut-and-paste method and the Israel-Darmois formalism, we analytically derive the surface stress–energy components and formulate the corresponding effective potential governing the dynamics of the wormhole throat. To assess stability under linear radial perturbations, we analyze the second derivative of the potential and derive exact expressions for the equation of state parameters for three different matter models: barotropic, phantomlike variable, and Chaplygin variable equation of state. These expressions are inserted to obtain physically consistent and constraint-driven stability conditions. Our results show that the stability of the wormhole configurations is highly sensitive to the black hole parameters. We find that increasing the charge significantly enhances the stability regions, while moderate values of <span><math><mrow><mi>β</mi><mo>≈</mo><mn>2</mn></mrow></math></span> yield optimal stability. Among the three equation of state models, the Chaplygin variable equation of state offers the most robust and extended stable configurations, particularly for small values of the radial dependence parameter <span><math><mi>n</mi></math></span>, outperforming the barotropic and phantomlike models in maintaining equilibrium with minimal exotic matter.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102084"},"PeriodicalIF":6.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal phase transitions, evaporation, and shadows of regular black holes in extended gravity with stringy matter","authors":"Muhammad Danish Sultan ,&nbsp;Shahid Chaudhary ,&nbsp;Talha Anwar ,&nbsp;Asifa Ashraf ,&nbsp;Ali M. Mubaraki ,&nbsp;Farruh Atamurotov ,&nbsp;Awatef Abidi","doi":"10.1016/j.dark.2025.102077","DOIUrl":"10.1016/j.dark.2025.102077","url":null,"abstract":"<div><div>The thermodynamics and quantum nature of black holes remain central to advancing our understanding of gravity, quantum mechanics, and high-energy physics. Motivated by the inadequacy of classical electrodynamics in extreme gravitational regimes and inspired by string theory’s prediction of extended matter structures, this work explores the rich interplay between nonlinear electrodynamics (NLED) and a surrounding cloud of strings on black hole physics. We present a novel class of regular AdS black holes within the framework of Einstein gravity, modified by both magnetic NLED sources and a cloud of strings, and perform an extensive investigation into their thermodynamic behavior, evaporation dynamics, and observational characteristics. A key motivation is to uncover whether exotic fields and high-energy corrections can alter classical predictions and stabilize black holes against evaporation. Our analysis reveals several striking results: (i) the deviation parameter <span><math><mi>k</mi></math></span>, magnetic charge <span><math><mi>g</mi></math></span>, and string cloud parameter <span><math><mi>a</mi></math></span> act as regulators of black hole thermodynamics, significantly suppressing Hawking radiation and extending black hole lifetimes; (ii) Joule–Thomson expansion shows that increasing <span><math><mi>k</mi></math></span> and <span><math><mi>a</mi></math></span> enhances thermal stability by eliminating heating phases and broadening cooling regions; (iii) quantum gravity corrections to entropy induce richer and more complex phase transitions than those in classical models, with the HPEM thermodynamic geometry consistently identifying critical points; (iv) scalar perturbation and greybody factor analyses indicate stronger damping and reduced radiation escape under higher <span><math><mi>k</mi></math></span>, <span><math><mi>a</mi></math></span>, or <span><math><mi>g</mi></math></span>, suggesting suppressed quasinormal modes and observable deviations in gravitational wave signatures; and (v) the black hole shadow radius shrinks under the influence of all three parameters, opening new possibilities for observational constraints via horizon-scale imaging.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102077"},"PeriodicalIF":6.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dark matter and collider phenomenology in radiative Type-III seesaw model with two inert doublets","authors":"Tapender,&nbsp;Labh Singh,&nbsp;Surender Verma","doi":"10.1016/j.dark.2025.102085","DOIUrl":"10.1016/j.dark.2025.102085","url":null,"abstract":"<div><div>We investigate a minimal Type-III scotogenic model featuring two inert scalar doublets and a hyperchargeless triplet fermion. The scalar sector, in addition to the Standard Model Higgs, includes a rich spectrum of dark scalars comprising two CP-even, two CP-odd, and two charged states. This framework gives rise to two viable dark matter candidates: the lightest CP-even dark scalar and the neutral component of the triplet fermion. We perform a comprehensive analysis of both dark matter scenarios, carefully examining their viability under the umbrella of theoretical consistency conditions and experimental constraints. In the inert scalar DM scenario, a significant parameter space emerges below 500 GeV—a region often dubbed the “desert region” in the conventional inert doublet model. Also, in the fermionic DM scenario, a new viable region is identified for DM mass below 2.5 TeV. Furthermore, our extended framework predicts distinctive and novel signatures beyond the conventional collider signatures anticipated for Type-III scotogenic model with one inert doublet.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102085"},"PeriodicalIF":6.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Black holes in Lorentz-violating gravity: Thermodynamics, geometry, and particle dynamics","authors":"Ankit Anand ,&nbsp;Aditya Singh ,&nbsp;Anshul Mishra ,&nbsp;Saeed Noori Gashti ,&nbsp;Takol Tangphati ,&nbsp;Phongpichit Channuie","doi":"10.1016/j.dark.2025.102086","DOIUrl":"10.1016/j.dark.2025.102086","url":null,"abstract":"<div><div>We investigate the thermodynamics, topology, and geometry of black holes in Lorentz-violating gravity. Modifications in the theory by perturbative parameter lead to coupled changes in horizon structure and thermodynamic behavior, allowing us to derive generalized universal relations and explore implications for the Weak Gravity Conjecture. The thermodynamic topology reveals distinct topological charges, with photon spheres identified as robust topological defects. Our analysis shows that the Ruppeiner curvature remains universally negative across thermodynamic ensembles, indicating dominant attractive interactions among microstructures. This ensemble-independent behavior highlights a fundamental thermodynamic universality in Lorentz-violating settings. Together, these results provide a consistent and rich framework for understanding black hole microphysics and gravitational consistency in modified theories. We further study the motion of timelike test particles in these black hole spacetimes by analyzing the effective potential shaped by the Lorentz-violating couplings. The resulting dynamics reveal the existence of bound orbits and stable circular trajectories, with the location of the innermost stable circular orbit and turning points significantly influenced by the parameters <span><math><msub><mrow><mi>ℓ</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></math></span>, and the cosmological constant. Numerical simulations of trajectories in the <span><math><mrow><mi>x</mi><mo>−</mo><mi>y</mi><mo>,</mo><mspace></mspace><mi>x</mi><mo>−</mo><mi>z</mi></mrow></math></span>, and 3D planes show precessing, bounded, and plunging orbits, depending on the particle’s specific energy and angular momentum. These results highlight how Lorentz-violating effects alter the structure of geodesic motion and provide potential observational signatures in the dynamics of massive particles near black holes.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102086"},"PeriodicalIF":6.4,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scalar perturbations of spacetime, greybody factors, weak deflection angles and shadows of black holes in Weyl geometric gravity theory","authors":"Shahid Chaudhary ,&nbsp;Muhammad Danish Sultan ,&nbsp;Asifa Ashraf ,&nbsp;Ali M. Mubaraki ,&nbsp;Saad Althobaiti ,&nbsp;Farruh Atamurotov ,&nbsp;Awatef Abidi","doi":"10.1016/j.dark.2025.102083","DOIUrl":"10.1016/j.dark.2025.102083","url":null,"abstract":"<div><div>We present a comprehensive theoretical investigation of black holes within the framework of Weyl geometric gravity which is a conformally invariant extension of General Relativity that naturally incorporates scalar and vector fields. Motivated by the growing need to explore gravitational dynamics beyond Einsteins theory particularly in regimes involving dark energy, dark matter, and quantum gravity we analyze a recently proposed Weyl black hole solution and uncover rich physical phenomena that depart significantly from classical expectations. Our study spans scalar perturbation dynamics, Hawking radiation via greybody factors, gravitational lensing in both vacuum and plasma environments, and shadow formation under infalling spherical accretion. We find that the Weyl coupling parameter <span><math><mi>δ</mi></math></span> and the cosmological curvature term <span><math><mrow><mn>1</mn><mo>/</mo><msup><mrow><mi>l</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> act as powerful deformation parameters which significantly enhancing the black holes stability, effecting Hawking radiation, and enlarging and distorting shadow images. Using the Gauss–Bonnet theorem and Jacobi metric formalism, we derive novel analytical expressions for the deflection angles of photons and massive particles demonstrating pronounced velocity dependence and curvature-induced amplification of gravitational lensing. Furthermore, our optical modeling reveals that Weyl geometric effects leave distinct imprints on observed intensities and photon rings.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102083"},"PeriodicalIF":6.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Particle dynamics and thermal properties in Kalb–Ramond ModMax black holes: Theoretical predictions for observational tests of exotic physics","authors":"Ahmad Al-Badawi ,&nbsp;Faizuddin Ahmed ,&nbsp;İzzet Sakallı","doi":"10.1016/j.dark.2025.102076","DOIUrl":"10.1016/j.dark.2025.102076","url":null,"abstract":"<div><div>We present a comprehensive theoretical study of geodesic motion and thermodynamic behavior in Kalb–Ramond (KR) black hole (BH) spacetimes sourced by ModMax electrodynamics. Both neutral and charged test particle dynamics are investigated, highlighting how the Lorentz symmetry breaking (LSB) parameter <span><math><mi>ℓ</mi></math></span>, the ModMax nonlinearity parameter <span><math><mi>γ</mi></math></span>, and the discrete branch parameter <span><math><mi>ζ</mi></math></span> significantly modify orbital structures compared to classical Schwarzschild and Reissner–Nordström (RN) solutions. Effective potential analysis reveals notable shifts in the innermost stable circular orbit (ISCO): ordinary branches allow stable orbits closer to the horizon, while phantom branches shift them outward by factors of 5–10. For charged particles, the combined influence of modified gravity and nonlinear electromagnetic fields may induce chaotic trajectories in certain regimes. On the thermodynamic side, we derive full expressions for Hawking temperature, entropy, and Helmholtz free energy. Ordinary branches exhibit divergent specific heat indicating second-order phase transitions, whereas phantom branches yield consistently negative specific heat, implying thermal instability. Phantom BHs are found to possess higher Hawking temperatures and show distinct thermodynamic phase structures, including Hawking–Page-type transitions. Observational features such as BH shadows and gravitational lensing are explored, revealing parameter-dependent changes in photon sphere radii and deflection angles. Notably, the deflection angle analysis via the Gauss–Bonnet theorem method (GBTm) shows opposite-sign electromagnetic corrections for phantom versus ordinary branches, suggesting potential observational discriminants.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102076"},"PeriodicalIF":6.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Minimally complex fuzzy wormhole models in Einstein-Cartan theory of gravity","authors":"Z. Yousaf ,&nbsp;M. Rizwan ,&nbsp;Mohammad Alshammari ,&nbsp;Othman Abdullah Almatroud ,&nbsp;Saleh Alshammari ,&nbsp;M. Mossa Al-sawalha","doi":"10.1016/j.dark.2025.102082","DOIUrl":"10.1016/j.dark.2025.102082","url":null,"abstract":"<div><div>In this work, we explore the possibility of constructing minimally complex wormhole geometries supported by fuzzy dark matter, framed within the Einstein-Cartan gravity model. By using the realistic Einasto density profile to model dark matter haloes, we reveal how dark matter distributions can form and affect wormhole structures. The matter content is an anisotropic fluid with Weyssenhoff spin contributions, effectively including quantum spin effects in the relativistic anisotropic energy–momentum tensor. The wormhole shape function is determined by solving the field equations and the Einasto profile. We then probe further into the dark matter’s role in dictating important physical properties of the wormhole, such as the complexity factor, equation of state, equilibrium status, energy limits, and active gravitational mass. To further complement our results, a detailed graphical analysis is included, illustrating how dark matter can dictate the geometry and physical feasibility of such extreme spacetime geometries.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102082"},"PeriodicalIF":6.4,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lorentz-violating ModMax black holes in phantom-enhanced Kalb–Ramond gravity: Thermodynamics and topological charges","authors":"Y. Sekhmani ,&nbsp;S.K. Maurya ,&nbsp;J. Rayimbaev ,&nbsp;M. Altanji ,&nbsp;I. Ibragimov ,&nbsp;S. Muminov","doi":"10.1016/j.dark.2025.102079","DOIUrl":"10.1016/j.dark.2025.102079","url":null,"abstract":"<div><div>We derive exact static, spherically symmetric black hole (BH) solutions within the framework of four-dimensional Einstein gravity, coupled to ModMax nonlinear electrodynamics and a Kalb–Ramond two-form. This coupling is governed by a discrete sign parameter, denoted as <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>±</mo><mn>1</mn></mrow></math></span>. In the ”ordinary” branch (<span><math><mrow><mi>ζ</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span>), the metric features both Cauchy and event horizons, while the electromagnetic stress–energy adheres to all classical energy conditions. In contrast, the ”phantom” branch (<span><math><mrow><mi>ζ</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span>) accommodates only a single horizon and simultaneously violates the weak, null, and strong conditions, which reflects genuine ghost-matter behaviour. The thermodynamic behaviour for <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span> results in multiple divergences in heat capacity and presents a distinctive swallowtail pattern in the AdS Gibbs free energy, indicative of a first-order phase transition that encompasses small, intermediate, and large phases. In contrast, for <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span>, there is only a single divergence observed, accompanied by a smooth Gibbs curve with no van der Waals-type oscillatory behaviour, which precludes the possibility of true coexistence. Topological analysis using Duan’s <span><math><mi>φ</mi></math></span>-mapping in AdS further differentiates the branches by examining their winding numbers. For <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span>, the winding numbers are <span><math><mrow><mo>(</mo><mo>+</mo><mn>1</mn><mo>,</mo><mo>−</mo><mn>1</mn><mo>,</mo><mo>+</mo><mn>1</mn><mo>)</mo></mrow></math></span>, resulting in a total topological charge (net winding number) of <span><math><mrow><mi>W</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span>. In contrast, for <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span>, the winding numbers are <span><math><mrow><mo>(</mo><mo>−</mo><mn>1</mn><mo>,</mo><mo>+</mo><mn>1</mn><mo>)</mo></mrow></math></span>, leading to a total topological charge of <span><math><mrow><mi>W</mi><mo>=</mo><mn>0</mn></mrow></math></span>. This distinction assigns a clear topological charge, which differentiates between the first-order transitions associated with <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span> and the smooth, latent-heat-free phase changes linked to <span><math><mrow><mi>ζ</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span>. Overall, <span><math><mi>ζ</mi></math></span> serves as the primary determinant influencing causal structure, energy condition profiles, critical phenomena, and topological charge in ModMax-Kalb-Ramond BH.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102079"},"PeriodicalIF":6.4,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}