Pub Date : 2025-10-24DOI: 10.1016/j.dark.2025.102145
Vivekanand Mohapatra
We investigate the impact of dark matter (DM) annihilation on the global 21-cm signal during the dark ages and cosmic dawn eras. The 21-cm line provides a complementary probe for studying the nature of dark matter beyond standard cosmological observables. In the standard CDM framework, the expected absorption amplitude of the dark ages global 21-cm signal is approximately . However, energy injection from DM annihilation can significantly heat and ionize the intergalactic medium, potentially altering or even erasing this absorption feature. We evaluate the thermal and ionization history of the gas to derive an upper bound on using the dark ages signal, which is free from astrophysical uncertainties. After incorporating observational and theoretical uncertainties arising from future lunar-based experiments and variations in cosmological parameters, respectively — we obtain a conservative upper limit of . This constraint is stronger than the bounds derived from Planck (2018) data for mass .
{"title":"Cosmological bounds on dark matter annihilation using dark ages 21-cm signal","authors":"Vivekanand Mohapatra","doi":"10.1016/j.dark.2025.102145","DOIUrl":"10.1016/j.dark.2025.102145","url":null,"abstract":"<div><div>We investigate the impact of dark matter (DM) annihilation on the global 21-cm signal during the dark ages and cosmic dawn eras. The 21-cm line provides a complementary probe for studying the nature of dark matter beyond standard cosmological observables. In the standard <span><math><mi>Λ</mi></math></span>CDM framework, the expected absorption amplitude of the dark ages global 21-cm signal is approximately <span><math><mrow><mo>−</mo><mn>42</mn><mspace></mspace><mi>mK</mi></mrow></math></span>. However, energy injection from DM annihilation can significantly heat and ionize the intergalactic medium, potentially altering or even erasing this absorption feature. We evaluate the thermal and ionization history of the gas to derive an upper bound on <span><math><mrow><msubsup><mrow><mi>f</mi></mrow><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mrow><mo>〈</mo><mi>σ</mi><mi>v</mi><mo>〉</mo></mrow><mo>/</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>χ</mi></mrow></msub></mrow></math></span> using the dark ages signal, which is free from astrophysical uncertainties. After incorporating observational and theoretical uncertainties arising from future lunar-based experiments and variations in cosmological parameters, respectively — we obtain a conservative upper limit of <span><math><mrow><msubsup><mrow><mi>f</mi></mrow><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mrow><mo>〈</mo><mi>σ</mi><mi>v</mi><mo>〉</mo></mrow><mo>/</mo><msub><mrow><mi>M</mi></mrow><mrow><mi>χ</mi></mrow></msub><mo>≲</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>27</mn></mrow></msup><mspace></mspace><msup><mrow><mi>cm</mi></mrow><mrow><mn>3</mn></mrow></msup><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mspace></mspace><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. This constraint is stronger than the bounds derived from Planck (2018) data for mass <span><math><mrow><mo>≲</mo><mn>10</mn><mspace></mspace><mi>GeV</mi></mrow></math></span>.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102145"},"PeriodicalIF":6.4,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362137","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}
Pub Date : 2025-10-21DOI: 10.1016/j.dark.2025.102146
Y. Sekhmani , G.G. Luciano , S.K. Maurya , J. Rayimbaev , M.K. Jasim , I. Ibragimov , S. Muminov
We study the thermodynamic topology and microscopic interaction properties of charged black holes in RegMax gravity, focusing on the role of the coupling parameter . Using the Duan topological current method together with Ruppeiner geometry, we show that controls a sharp change in phase structure. Above a certain critical threshold, we find that the Duan defect curve develops an intermediate branch and vertical tangency points, producing continuous (second-order) critical behaviour. Furthermore, the Ruppeiner curvature becomes negative at very small horizon radii before turning positive and progressively vanishing at larger radii. By contrast, below the critical value of the coupling, the intermediate black hole phase disappears, and the system shows a simpler small/large first-order/coexistence behaviour driven by free-energy competition. In this regime, the Ruppeiner curvature remains predominantly positive. Overall, increasing enriches the thermodynamic topology (allowing for second-order criticality) while simultaneously reducing the domain in which classical energy conditions (ECs) are satisfied, thus linking exotic thermodynamic behaviour to more severe violations of standard energy conditions.
{"title":"Topological signatures and geometrothermodynamics of critical phenomena in regularized Maxwell black holes","authors":"Y. Sekhmani , G.G. Luciano , S.K. Maurya , J. Rayimbaev , M.K. Jasim , I. Ibragimov , S. Muminov","doi":"10.1016/j.dark.2025.102146","DOIUrl":"10.1016/j.dark.2025.102146","url":null,"abstract":"<div><div>We study the thermodynamic topology and microscopic interaction properties of charged black holes in RegMax gravity, focusing on the role of the coupling parameter <span><math><mi>α</mi></math></span>. Using the Duan topological current method together with Ruppeiner geometry, we show that <span><math><mi>α</mi></math></span> controls a sharp change in phase structure. Above a certain critical threshold, we find that the Duan defect curve develops an intermediate branch and vertical tangency points, producing continuous (second-order) critical behaviour. Furthermore, the Ruppeiner curvature becomes negative at very small horizon radii before turning positive and progressively vanishing at larger radii. By contrast, below the critical value of the coupling, the intermediate black hole phase disappears, and the system shows a simpler small/large first-order/coexistence behaviour driven by free-energy competition. In this regime, the Ruppeiner curvature remains predominantly positive. Overall, increasing <span><math><mi>α</mi></math></span> enriches the thermodynamic topology (allowing for second-order criticality) while simultaneously reducing the domain in which classical energy conditions (ECs) are satisfied, thus linking exotic thermodynamic behaviour to more severe violations of standard energy conditions.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102146"},"PeriodicalIF":6.4,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362129","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}
Pub Date : 2025-10-20DOI: 10.1016/j.dark.2025.102138
Viktor Stasenko
Primordial black hole (PBH) binaries experience strong gravitational perturbations in the case of their initial clustering, which significantly affects the dynamics of their mergers. In this work, we develop a new formalism to account for these perturbations and track the evolution of the binary orbital parameters distribution. Based on this approach, we calculate the merger rate of PBH binaries and demonstrate that its temporal evolution differs greatly from that of isolated binary systems. Moreover, PBH clustering produces distinctive features in the stochastic gravitational-wave background: the canonical spectral slope transforms to in a certain frequency band. These predictions can be probed in future gravitational wave observations, opening up new opportunities to test the clustering of PBHs and their contribution to dark matter.
{"title":"Merger history of clustered primordial black holes","authors":"Viktor Stasenko","doi":"10.1016/j.dark.2025.102138","DOIUrl":"10.1016/j.dark.2025.102138","url":null,"abstract":"<div><div>Primordial black hole (PBH) binaries experience strong gravitational perturbations in the case of their initial clustering, which significantly affects the dynamics of their mergers. In this work, we develop a new formalism to account for these perturbations and track the evolution of the binary orbital parameters distribution. Based on this approach, we calculate the merger rate of PBH binaries and demonstrate that its temporal evolution differs greatly from that of isolated binary systems. Moreover, PBH clustering produces distinctive features in the stochastic gravitational-wave background: the canonical <span><math><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></math></span> spectral slope transforms to <span><math><mrow><msub><mrow><mi>Ω</mi></mrow><mrow><mi>gw</mi></mrow></msub><mo>∝</mo><msup><mrow><mi>ν</mi></mrow><mrow><mo>−</mo><mn>65</mn><mo>/</mo><mn>28</mn></mrow></msup></mrow></math></span> in a certain frequency band. These predictions can be probed in future gravitational wave observations, opening up new opportunities to test the clustering of PBHs and their contribution to dark matter.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102138"},"PeriodicalIF":6.4,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362130","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}
Pub Date : 2025-10-19DOI: 10.1016/j.dark.2025.102143
Kang Jiao , Tong-Jie Zhang , Liang Gao , Yun Chen
We present a geometric embedding method that exploits the exact kinematic relation to transform redshift misalignment between Cosmic Chronometer (CC) and Sandage-Loeb (SL) datasets into fundamental constraints in observable space. The approach recognizes that encodes the orientation of the FLRW observational plane defined by coordinates, enabling direct algebraic determination without parametric assumptions or interpolation schemes. Validation using available CC measurements and forecasted redshift drift data from FAST, CHIME, SKA, and ELT demonstrates 1.9% precision for optimal data combinations, yielding km s−1 Mpc−1 while maintaining complete cosmological model independence. While no actual SL measurements currently exist, requiring us to rely on simulations for validation, our geometric constraints show superior resilience against sparse redshift coverage compared to Gaussian Process (GP) methods, which exhibit systematic biases and large uncertainties when datasets lack substantial overlap. This kinematic framework establishes geometric embedding as a robust tool for precision cosmological measurements, offering a fundamentally different approach to determination through pure observational analysis based on FLRW kinematic principles. The full potential of this method awaits implementation with real SL measurements from next-generation facilities.
我们提出了一种几何嵌入方法，利用精确的运动学关系z0 =H0(1+z)−H(z)将Cosmic Chronometer （CC）和Sandage-Loeb （SL）数据集之间的红移错位转换为可观测空间中的基本约束。该方法认识到H0编码由（z，H(z), z）坐标定义的FLRW观测平面的方向，无需参数假设或插值方案即可直接进行代数确定。利用现有的CC测量数据和来自FAST、CHIME、SKA和ELT的预测红移漂移数据进行验证，结果表明，最佳数据组合的精度为1.9%，得到的H0=66.26±1.26 km s−1 Mpc−1，同时保持了完全的宇宙学模型独立性。虽然目前没有实际的SL测量，需要我们依靠模拟来验证，但与高斯过程（GP）方法相比，我们的几何约束显示出对稀疏红移覆盖的优越弹性，高斯过程（GP）方法在数据集缺乏大量重叠时表现出系统偏差和较大的不确定性。该运动学框架建立了几何嵌入作为精确宇宙学测量的强大工具，提供了一种完全不同的方法，通过基于FLRW运动学原理的纯观测分析来确定H0。该方法的全部潜力有待于下一代设备的实际SL测量实现。
{"title":"FLRW kinematic-induced measurement of the Hubble constant from Cosmic Chronometer and redshift drift observations","authors":"Kang Jiao , Tong-Jie Zhang , Liang Gao , Yun Chen","doi":"10.1016/j.dark.2025.102143","DOIUrl":"10.1016/j.dark.2025.102143","url":null,"abstract":"<div><div>We present a geometric embedding method that exploits the exact kinematic relation <span><math><mrow><mover><mrow><mi>z</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>=</mo><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow><mo>−</mo><mi>H</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> to transform redshift misalignment between Cosmic Chronometer (CC) and Sandage-Loeb (SL) datasets into fundamental constraints in observable space. The approach recognizes that <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> encodes the orientation of the FLRW observational plane defined by <span><math><mrow><mo>(</mo><mi>z</mi><mo>,</mo><mi>H</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow><mo>,</mo><mover><mrow><mi>z</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>)</mo></mrow></math></span> coordinates, enabling direct algebraic determination without parametric assumptions or interpolation schemes. Validation using available CC measurements and forecasted redshift drift data from FAST, CHIME, SKA, and ELT demonstrates 1.9% precision for optimal data combinations, yielding <span><math><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mn>66</mn><mo>.</mo><mn>26</mn><mo>±</mo><mn>1</mn><mo>.</mo><mn>26</mn></mrow></math></span> km s<sup>−1</sup> Mpc<sup>−1</sup> while maintaining complete cosmological model independence. While no actual SL measurements currently exist, requiring us to rely on simulations for validation, our geometric constraints show superior resilience against sparse redshift coverage compared to Gaussian Process (GP) methods, which exhibit systematic biases and large uncertainties when datasets lack substantial overlap. This kinematic framework establishes geometric embedding as a robust tool for precision cosmological measurements, offering a fundamentally different approach to <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> determination through pure observational analysis based on FLRW kinematic principles. The full potential of this method awaits implementation with real SL measurements from next-generation facilities.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102143"},"PeriodicalIF":6.4,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362131","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}
Pub Date : 2025-10-18DOI: 10.1016/j.dark.2025.102139
Mohammad Reza Alipour , Yassine Sekhmani , Saeed Noori Gashti , Mohammad Ali S. Afshar , Behnam Pourhassan , İzzet Sakallı , Jafar Sadeghi , Javlon Rayimbaev
This study investigates the thermodynamic topology of charged black holes within a Lorentz symmetry violation framework, examining how key parameters influence the distribution and nature of topological charges. By parametrically examining the black hole, we found two distinct topological charges, which sum to zero, indicating Reissner–Nordström phase transitions in the black hole system. Our analysis of charged black holes with Kalb–Ramond field modifications reveals consistent topological patterns that align with established Reissner–Nordström thermodynamic behaviors. The investigation of photon sphere topology demonstrates discrete topological charges that depend on orientation while maintaining fixed total charge across parameter variations. These findings illuminate the intricate relationship between thermodynamic topology and gravitational structures, advancing the classification and stability analysis of black holes subject to Lorentz symmetry violation. Additionally, we analyze vertical and azimuthal frequencies alongside periastron precession rates in charged Kalb–Ramond black hole spacetimes. Our results show that electric charge enhances oscillation frequencies and precession peaks, while Kalb–Ramond coupling mitigates these effects by reducing oscillation rates and precession in the strong-field regime. These modulations are most pronounced near the innermost stable circular orbit and diminish at larger radii, confirming that Kalb–Ramond corrections are localized to the near-horizon region. Such characteristic signatures in quasi-periodic oscillations and orbital precession provide valuable observational probes for testing theoretical extensions to General Relativity that incorporate electromagnetic and Kalb–Ramond fields.
{"title":"Topological thermodynamics and observable signatures of charged black holes in modified gravity","authors":"Mohammad Reza Alipour , Yassine Sekhmani , Saeed Noori Gashti , Mohammad Ali S. Afshar , Behnam Pourhassan , İzzet Sakallı , Jafar Sadeghi , Javlon Rayimbaev","doi":"10.1016/j.dark.2025.102139","DOIUrl":"10.1016/j.dark.2025.102139","url":null,"abstract":"<div><div>This study investigates the thermodynamic topology of charged black holes within a Lorentz symmetry violation framework, examining how key parameters influence the distribution and nature of topological charges. By parametrically examining the black hole, we found two distinct topological charges, which sum to zero, indicating Reissner–Nordström phase transitions in the black hole system. Our analysis of charged black holes with Kalb–Ramond field modifications reveals consistent topological patterns that align with established Reissner–Nordström thermodynamic behaviors. The investigation of photon sphere topology demonstrates discrete topological charges that depend on orientation while maintaining fixed total charge across parameter variations. These findings illuminate the intricate relationship between thermodynamic topology and gravitational structures, advancing the classification and stability analysis of black holes subject to Lorentz symmetry violation. Additionally, we analyze vertical and azimuthal frequencies alongside periastron precession rates in charged Kalb–Ramond black hole spacetimes. Our results show that electric charge enhances oscillation frequencies and precession peaks, while Kalb–Ramond coupling mitigates these effects by reducing oscillation rates and precession in the strong-field regime. These modulations are most pronounced near the innermost stable circular orbit and diminish at larger radii, confirming that Kalb–Ramond corrections are localized to the near-horizon region. Such characteristic signatures in quasi-periodic oscillations and orbital precession provide valuable observational probes for testing theoretical extensions to General Relativity that incorporate electromagnetic and Kalb–Ramond fields.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102139"},"PeriodicalIF":6.4,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362136","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}
Pub Date : 2025-10-18DOI: 10.1016/j.dark.2025.102141
Shuo Lu, Tao Zhu
In this work, we investigate the gravitational wave emission from the periodic orbital motion of a test particle around two specific types of black holes in Einstein-Æther theory, a modified gravity that locally breaks Lorentz symmetry while remaining consistent with theoretical and observational constraints through a careful selection of its four coupling constants . Focusing on the impact of the æther field, we examine the properties of periodic orbits, which are characterized by a set of three topological integers that uniquely classify their trajectories. We then calculate the gravitational waveforms generated by these periodic orbits, identifying potential observational signatures. Our analysis reveals a direct connection between the zoom-whirl orbital behavior of the small compact object and the gravitational waveforms it emits: higher zoom numbers lead to increasingly intricate waveform substructures. Moreover, the presence of the æther field introduces significant modifications to these waveforms, imprinting measurable deviations that could be potentially tested or constrained by future space-based gravitational wave detectors.
{"title":"Gravitational radiations from periodic orbits around Einstein-Æther black holes","authors":"Shuo Lu, Tao Zhu","doi":"10.1016/j.dark.2025.102141","DOIUrl":"10.1016/j.dark.2025.102141","url":null,"abstract":"<div><div>In this work, we investigate the gravitational wave emission from the periodic orbital motion of a test particle around two specific types of black holes in Einstein-Æther theory, a modified gravity that locally breaks Lorentz symmetry while remaining consistent with theoretical and observational constraints through a careful selection of its four coupling constants <span><math><msub><mrow><mi>c</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>. Focusing on the impact of the æther field, we examine the properties of periodic orbits, which are characterized by a set of three topological integers <span><math><mrow><mo>(</mo><mi>z</mi><mo>,</mo><mi>w</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></math></span> that uniquely classify their trajectories. We then calculate the gravitational waveforms generated by these periodic orbits, identifying potential observational signatures. Our analysis reveals a direct connection between the zoom-whirl orbital behavior of the small compact object and the gravitational waveforms it emits: higher zoom numbers lead to increasingly intricate waveform substructures. Moreover, the presence of the æther field introduces significant modifications to these waveforms, imprinting measurable deviations that could be potentially tested or constrained by future space-based gravitational wave detectors.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102141"},"PeriodicalIF":6.4,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362135","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}
Pub Date : 2025-10-17DOI: 10.1016/j.dark.2025.102136
Saeed Noori Gashti , Ankit Anand , Aditya Singh , Anshul Mishra , Mohammad Ali S. Afshar , Mohammad Reza Alipour , İzzet Sakallı , Behnam Pourhassan , Jafar Sadeghi
This work investigates the thermodynamic topology of accelerating charged Anti-de Sitter (AdS) black holes within the framework of Rainbow Gravity. By examining vector field configurations, we identify distinct zero points that correspond to localized topological charges. These topological characteristics remain globally conserved under variations of physical parameters, highlighting the robustness of the system’s topological structure—closely resembling the behavior seen in AdS Reissner–Nordström black holes. The acceleration parameter is shown to play a decisive role in shaping these configurations. In addition, the extended thermodynamic formalism is applied to construct a geometric description in the entropy–pressure plane, allowing microscopic interactions to be characterized through scalar curvature analysis. This thermodynamic curvature effectively encodes stability properties and phase transitions, distinguishing between attractive and repulsive interactions within the black hole microstructure. Overall, the findings provide new insights into the microstructure, stability, and phase behavior of black holes, clarifying the interplay between acceleration and Rainbow Gravity effects.
{"title":"Thermodynamic scalar curvature and topological classification in accelerating charged AdS black holes under rainbow gravity","authors":"Saeed Noori Gashti , Ankit Anand , Aditya Singh , Anshul Mishra , Mohammad Ali S. Afshar , Mohammad Reza Alipour , İzzet Sakallı , Behnam Pourhassan , Jafar Sadeghi","doi":"10.1016/j.dark.2025.102136","DOIUrl":"10.1016/j.dark.2025.102136","url":null,"abstract":"<div><div>This work investigates the thermodynamic topology of accelerating charged Anti-de Sitter (AdS) black holes within the framework of Rainbow Gravity. By examining vector field configurations, we identify distinct zero points that correspond to localized topological charges. These topological characteristics remain globally conserved under variations of physical parameters, highlighting the robustness of the system’s topological structure—closely resembling the behavior seen in AdS Reissner–Nordström black holes. The acceleration parameter is shown to play a decisive role in shaping these configurations. In addition, the extended thermodynamic formalism is applied to construct a geometric description in the entropy–pressure <span><math><mrow><mo>(</mo><mi>S</mi><mo>,</mo><mi>P</mi><mo>)</mo></mrow></math></span> plane, allowing microscopic interactions to be characterized through scalar curvature analysis. This thermodynamic curvature effectively encodes stability properties and phase transitions, distinguishing between attractive and repulsive interactions within the black hole microstructure. Overall, the findings provide new insights into the microstructure, stability, and phase behavior of black holes, clarifying the interplay between acceleration and Rainbow Gravity effects.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102136"},"PeriodicalIF":6.4,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362132","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}
The Einstein–Cartan (EC) theory of gravity provides a natural extension of general relativity by incorporating spacetime torsion to account for the intrinsic spin of matter. In this work, we investigate Yukawa-Casimir traversable wormholes supported by three distinct Yukawa-Casimir energy density profiles within the framework of EC gravity. The resulting shape functions are shown to satisfy all the fundamental requirements for traversable wormhole geometries. Our analysis reveals that the presence of exotic matter is unavoidable in sustaining these wormholes, and we quantify its total amount through the volume integral quantifier. Furthermore, the equilibrium of the wormhole configurations is established by examining the Tolman–Oppenheimer–Volkoff equation. To enhance the physical relevance of the present work, we study several key features of the wormholes, including the embedding surface, proper radial distance, tidal forces, and total gravitational energy. In addition, we analyze the optical properties of wormholes by examining both the shadow and the strong deflection angle. All the findings collectively demonstrate the physical plausibility of Yukawa-Casimir traversable wormholes within the EC gravity framework.
{"title":"Yukawa-Casimir wormholes within Einstein–Cartan gravity framework","authors":"Nayan Sarkar , Susmita Sarkar , Abdelmalek Bouzenada","doi":"10.1016/j.dark.2025.102122","DOIUrl":"10.1016/j.dark.2025.102122","url":null,"abstract":"<div><div>The Einstein–Cartan (EC) theory of gravity provides a natural extension of general relativity by incorporating spacetime torsion to account for the intrinsic spin of matter. In this work, we investigate Yukawa-Casimir traversable wormholes supported by three distinct Yukawa-Casimir energy density profiles within the framework of EC gravity. The resulting shape functions are shown to satisfy all the fundamental requirements for traversable wormhole geometries. Our analysis reveals that the presence of exotic matter is unavoidable in sustaining these wormholes, and we quantify its total amount through the volume integral quantifier. Furthermore, the equilibrium of the wormhole configurations is established by examining the Tolman–Oppenheimer–Volkoff equation. To enhance the physical relevance of the present work, we study several key features of the wormholes, including the embedding surface, proper radial distance, tidal forces, and total gravitational energy. In addition, we analyze the optical properties of wormholes by examining both the shadow and the strong deflection angle. All the findings collectively demonstrate the physical plausibility of Yukawa-Casimir traversable wormholes within the EC gravity framework.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102122"},"PeriodicalIF":6.4,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362133","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}
Pub Date : 2025-10-15DOI: 10.1016/j.dark.2025.102135
Othman Abdullah Almatroud , M. Rizwan , M.Z. Bhatti , Mohammad Alshammari , Saleh Alshammari , Z. Yousaf
Within the framework of a specific type of dark matter halo, this article attempts to provide evidence for the existence of charged, traversable, and stable wormhole solutions. We study novel analytic and exact solutions of the Einstein–Maxwell equations, considering the impact of the Einasto density model, which describes fuzzy wormholes. To achieve this, we study the wormhole geometry by developing a shape function via the Einasto density model. The shape function that emerges from this process meets all the required criteria and connects the asymptotically flat spacetime regions. Analyzing the existence of stable traversable wormhole geometry involves checking the behavior of energy conditions, equation of state, conservation equation, and active gravitational mass in the presence of an electromagnetic field. Within this framework of dark matter haloes, traversable wormhole solutions are found to be both viable and stable. Moreover, the complexity factor analysis reveals that these solutions for wormholes are less complex.
{"title":"Electromagnetic fields and fuzzy wormholes","authors":"Othman Abdullah Almatroud , M. Rizwan , M.Z. Bhatti , Mohammad Alshammari , Saleh Alshammari , Z. Yousaf","doi":"10.1016/j.dark.2025.102135","DOIUrl":"10.1016/j.dark.2025.102135","url":null,"abstract":"<div><div>Within the framework of a specific type of dark matter halo, this article attempts to provide evidence for the existence of charged, traversable, and stable wormhole solutions. We study novel analytic and exact solutions of the Einstein–Maxwell equations, considering the impact of the Einasto density model, which describes fuzzy wormholes. To achieve this, we study the wormhole geometry by developing a shape function via the Einasto density model. The shape function that emerges from this process meets all the required criteria and connects the asymptotically flat spacetime regions. Analyzing the existence of stable traversable wormhole geometry involves checking the behavior of energy conditions, equation of state, conservation equation, and active gravitational mass in the presence of an electromagnetic field. Within this framework of dark matter haloes, traversable wormhole solutions are found to be both viable and stable. Moreover, the complexity factor analysis reveals that these solutions for wormholes are less complex.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102135"},"PeriodicalIF":6.4,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320524","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}
Pub Date : 2025-10-14DOI: 10.1016/j.dark.2025.102133
Tayyab Naseer , M. Sharif , Aleena Tehreem
In the context of the Einstein gravity theory, this investigation uses minimal geometric deformation to develop two exact extensions of the existing anisotropic solutions. In order to do this, we consider a static spherical interior that is initially filled with the anisotropic fluid, referred to a seed source. A Lagrangian corresponding to a new source is then introduced, taking into consideration that the parent fluid distribution is gravitationally linked with the new source. Two distinct systems of equations are produced after applying a transformation to the radial component following the computation of the field equations for the entire matter setup. Using different constraints, these sets are solved separately, producing novel solutions. Furthermore, matching criteria between the exterior and interior geometries are used to determine the constants appeared in the interior solutions. Afterwards, the graphical examination of the proposed models is carried out using the estimated mass and radius of a star candidate . Finally, we conclude that, for the considered choices of the decoupling parameter, our resulting relativistic models agree well with the acceptance criteria.
{"title":"Impact of gravitational decoupling on relativistic compact models admitting a linear equation of state","authors":"Tayyab Naseer , M. Sharif , Aleena Tehreem","doi":"10.1016/j.dark.2025.102133","DOIUrl":"10.1016/j.dark.2025.102133","url":null,"abstract":"<div><div>In the context of the Einstein gravity theory, this investigation uses minimal geometric deformation to develop two exact extensions of the existing anisotropic solutions. In order to do this, we consider a static spherical interior that is initially filled with the anisotropic fluid, referred to a seed source. A Lagrangian corresponding to a new source is then introduced, taking into consideration that the parent fluid distribution is gravitationally linked with the new source. Two distinct systems of equations are produced after applying a transformation to the radial component following the computation of the field equations for the entire matter setup. Using different constraints, these sets are solved separately, producing novel solutions. Furthermore, matching criteria between the exterior and interior geometries are used to determine the constants appeared in the interior solutions. Afterwards, the graphical examination of the proposed models is carried out using the estimated mass and radius of a star candidate <span><math><mrow><mi>V</mi><mi>e</mi><mi>l</mi><mi>a</mi><mspace></mspace><mi>X</mi><mo>−</mo><mn>1</mn></mrow></math></span>. Finally, we conclude that, for the considered choices of the decoupling parameter, our resulting relativistic models agree well with the acceptance criteria.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102133"},"PeriodicalIF":6.4,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320527","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号