Pub Date : 2025-10-31DOI: 10.1016/j.dark.2025.102153
Allan R.P Moreira , Faizuddin Ahmed , Abdelmalek Bouzenada
In this work, we investigate a novel class of static, spherically symmetric black hole (BH) solutions that incorporate several fundamental physical features: electric charge, Lorentz symmetry violation, a surrounding cloud of strings, and an external quintessence-like field. The proposed metric generalizes earlier configurations by including a Lorentz-violating deformation inspired by the Kalb-Ramond field vacuum expectation value. We analyze the dynamics of null geodesics and characterize the effective potential, photon trajectories, and the conditions for circular orbits, photon sphere, and shadow formation. We further study the scalar perturbations by solving the Klein–Gordon equation in the BH background, revealing how various geometric and physical parameters influence the scalar potential. Additionally, we examine the thermodynamic behavior of the solution, computing key quantities such as the mass, Hawking temperature, heat capacity, and Gibbs free energy.
{"title":"Geometric properties, scalar perturbations and thermodynamics of a charged Lorentz-violating hairy black hole with quintessence-like field","authors":"Allan R.P Moreira , Faizuddin Ahmed , Abdelmalek Bouzenada","doi":"10.1016/j.dark.2025.102153","DOIUrl":"10.1016/j.dark.2025.102153","url":null,"abstract":"<div><div>In this work, we investigate a novel class of static, spherically symmetric black hole (BH) solutions that incorporate several fundamental physical features: electric charge, Lorentz symmetry violation, a surrounding cloud of strings, and an external quintessence-like field. The proposed metric generalizes earlier configurations by including a Lorentz-violating deformation inspired by the Kalb-Ramond field vacuum expectation value. We analyze the dynamics of null geodesics and characterize the effective potential, photon trajectories, and the conditions for circular orbits, photon sphere, and shadow formation. We further study the scalar perturbations by solving the Klein–Gordon equation in the BH background, revealing how various geometric and physical parameters influence the scalar potential. Additionally, we examine the thermodynamic behavior of the solution, computing key quantities such as the mass, Hawking temperature, heat capacity, and Gibbs free energy.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102153"},"PeriodicalIF":6.4,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465214","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 : 2025-10-31DOI: 10.1016/j.dark.2025.102155
Fabiola Arevalo , Luis Firinguetti , Marcos Peña
The assumption of Gaussian distribution in Type Ia supernova data underlies most cosmological parameter estimates and led to the discovery of late acceleration. In this work, we assess the validity of this assumption using the Pantheon+ dataset and analyze its impact on parameter estimation for dark energy cosmological models.
We perform a comprehensive statistical, analysis including the Lilliefors and Jarque–Bera tests, to assess the normality of both the data and model residuals. We find that the Gaussianity assumption is untenable and that the redshift distribution is more accurately described by a t-distribution, as indicated by the Kolmogorov Smirnov test.
These statistical findings are explored within the framework of a nonlinear cosmological interaction for the dark sector. Free parameters are estimated using multiple methods, and bootstrap confidence intervals are constructed for them. Our results suggest that standard Gaussian assumptions may underestimate uncertainties in cosmological inference, and we advocate for incorporating more flexible statistical models in future analyses.
{"title":"On the Gaussian assumption in the estimation of parameters for dark energy models","authors":"Fabiola Arevalo , Luis Firinguetti , Marcos Peña","doi":"10.1016/j.dark.2025.102155","DOIUrl":"10.1016/j.dark.2025.102155","url":null,"abstract":"<div><div>The assumption of Gaussian distribution in Type Ia supernova data underlies most cosmological parameter estimates and led to the discovery of late acceleration. In this work, we assess the validity of this assumption using the Pantheon+ dataset and analyze its impact on parameter estimation for dark energy cosmological models.</div><div>We perform a comprehensive statistical, analysis including the Lilliefors and Jarque–Bera tests, to assess the normality of both the data and model residuals. We find that the Gaussianity assumption is untenable and that the redshift distribution is more accurately described by a t-distribution, as indicated by the Kolmogorov Smirnov test.</div><div>These statistical findings are explored within the framework of a nonlinear cosmological interaction for the dark sector. Free parameters are estimated using multiple methods, and bootstrap confidence intervals are constructed for them. Our results suggest that standard Gaussian assumptions may underestimate uncertainties in cosmological inference, and we advocate for incorporating more flexible statistical models in future analyses.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102155"},"PeriodicalIF":6.4,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465753","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 : 2025-10-31DOI: 10.1016/j.dark.2025.102151
Luis M. Nieto , Farokhnaz Hosseinifar , Kuantay Boshkayev , Soroush Zare , Hassan Hassanabadi
In this work, we analyze some characteristics and gravitational signatures of the Schwarzschild black hole immersed in a Hernquist dark matter halo. We determine the black hole’s remnant radius and mass, which provide useful residual information at the end of its evaporation, and we then explore the luminosity of the accretion disk for the model under study. In this way, we determine the key orbital parameters of the test particles within the accretion disk, such as angular velocity, angular momentum, energy, and the radius of the innermost stable circular orbit, based on the dark matter model parameters. We also numerically estimate the accretion disk’s efficiency in converting matter into radiation. We also demonstrate that dark matter, which significantly alters the geometry surrounding a Schwarzschild black hole, influences the accretion disk’s radiative flux, temperature, differential luminosity, and spectral luminosity. The stability of a black hole spacetime is determined in the eikonal regime. The Lyapunov exponent is also analyzed to quantify the stability of the particle regime and to demonstrate the infall into or escape from the black hole to infinity, as well as the quasi-normal modes. Finally, some properties of black holes are studied from a topological perspective.
{"title":"Accretion disk luminosity and topological characteristics for a Schwarzschild black hole surrounded by a Hernquist dark matter halo","authors":"Luis M. Nieto , Farokhnaz Hosseinifar , Kuantay Boshkayev , Soroush Zare , Hassan Hassanabadi","doi":"10.1016/j.dark.2025.102151","DOIUrl":"10.1016/j.dark.2025.102151","url":null,"abstract":"<div><div>In this work, we analyze some characteristics and gravitational signatures of the Schwarzschild black hole immersed in a Hernquist dark matter halo. We determine the black hole’s remnant radius and mass, which provide useful residual information at the end of its evaporation, and we then explore the luminosity of the accretion disk for the model under study. In this way, we determine the key orbital parameters of the test particles within the accretion disk, such as angular velocity, angular momentum, energy, and the radius of the innermost stable circular orbit, based on the dark matter model parameters. We also numerically estimate the accretion disk’s efficiency in converting matter into radiation. We also demonstrate that dark matter, which significantly alters the geometry surrounding a Schwarzschild black hole, influences the accretion disk’s radiative flux, temperature, differential luminosity, and spectral luminosity. The stability of a black hole spacetime is determined in the eikonal regime. The Lyapunov exponent is also analyzed to quantify the stability of the particle regime and to demonstrate the infall into or escape from the black hole to infinity, as well as the quasi-normal modes. Finally, some properties of black holes are studied from a topological perspective.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102151"},"PeriodicalIF":6.4,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415954","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 : 2025-10-30DOI: 10.1016/j.dark.2025.102148
Yuxuan Kang, Mingzhe Li, Yeheng Tong
Recently the modified teleparallel gravity models attracted a lot of interests. In this paper we consider more extensions to the New General Relativity (NGR) model with parity violations. This extended NGR model differs from the normal NGR model by the inclusion of additional parity-odd term that is quadratic in the torsion tensor. By investigating its cosmological perturbations of this model, we find that this model can avoid ghost instabilities in certain regions of the parameter space, where the coefficient of the parity-odd term does not vanish.
{"title":"Cosmological perturbations of extended NGR model with parity violation","authors":"Yuxuan Kang, Mingzhe Li, Yeheng Tong","doi":"10.1016/j.dark.2025.102148","DOIUrl":"10.1016/j.dark.2025.102148","url":null,"abstract":"<div><div>Recently the modified teleparallel gravity models attracted a lot of interests. In this paper we consider more extensions to the New General Relativity (NGR) model with parity violations. This extended NGR model differs from the normal NGR model by the inclusion of additional parity-odd term that is quadratic in the torsion tensor. By investigating its cosmological perturbations of this model, we find that this model can avoid ghost instabilities in certain regions of the parameter space, where the coefficient of the parity-odd term does not vanish.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102148"},"PeriodicalIF":6.4,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415951","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 : 2025-10-29DOI: 10.1016/j.dark.2025.102154
Giacomo D’Amico , Michele Doro , Michela De Caria
We present a novel method for both forecasting and recasting upper limits (ULs) on dark matter (DM) annihilation cross sections, , or decay lifetime . The forecasting method relies solely on the instrument response functions (IRFs) to predict ULs for a given observational setup, without the need for full analysis pipelines. The recasting procedure uses published ULs to reinterpret constraints for alternative DM models or channels. We demonstrate its utility across a range of canonical annihilation channels, including , , , and , and apply it to several major gamma-ray experiments, including MAGIC, Fermi-LAT, and CTAO. Notably, we develop a recasting approach that remains effective even when the IRF is unavailable by extracting generalized IRF-dependent coefficients from benchmark channels. We apply this method to reinterpret ULs derived from standard spectra (e.g., PPPC4DMID) in terms of more recent DM scenarios, including a Higgsino-like model with mixed final states and spectra generated with the CosmiXs model. Extensive Monte Carlo simulations and direct comparison with published results confirm the robustness and accuracy of our method, with discrepancies remaining within statistical uncertainties. The algorithm is generally applicable to any scenario where the expected signal model is parametric, offering a powerful tool for reinterpreting existing gamma-ray limits and efficiently exploring the DM parameter space in current and future indirect detection experiments.
{"title":"Recasting and forecasting dark matter limits without raw data: A generalized algorithm for gamma-ray telescopes","authors":"Giacomo D’Amico , Michele Doro , Michela De Caria","doi":"10.1016/j.dark.2025.102154","DOIUrl":"10.1016/j.dark.2025.102154","url":null,"abstract":"<div><div>We present a novel method for both forecasting and recasting upper limits (ULs) on dark matter (DM) annihilation cross sections, <span><math><msup><mrow><mfenced><mrow><mi>σ</mi><mi>v</mi></mrow></mfenced></mrow><mrow><mi>U</mi><mi>L</mi></mrow></msup></math></span>, or decay lifetime <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mi>L</mi><mi>L</mi></mrow></msup></math></span> . The forecasting method relies solely on the instrument response functions (IRFs) to predict ULs for a given observational setup, without the need for full analysis pipelines. The recasting procedure uses published ULs to reinterpret constraints for alternative DM models or channels. We demonstrate its utility across a range of canonical annihilation channels, including <span><math><mrow><mi>b</mi><mover><mrow><mi>b</mi></mrow><mrow><mo>̄</mo></mrow></mover></mrow></math></span>, <span><math><mrow><msup><mrow><mi>W</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>W</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math></span>, <span><math><mrow><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math></span>, and <span><math><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math></span>, and apply it to several major gamma-ray experiments, including MAGIC, <em>Fermi</em>-LAT, and CTAO. Notably, we develop a recasting approach that remains effective even when the IRF is unavailable by extracting generalized IRF-dependent coefficients from benchmark channels. We apply this method to reinterpret ULs derived from standard spectra (e.g., PPPC4DMID) in terms of more recent DM scenarios, including a Higgsino-like model with mixed final states and spectra generated with the CosmiXs model. Extensive Monte Carlo simulations and direct comparison with published results confirm the robustness and accuracy of our method, with discrepancies remaining within statistical uncertainties. The algorithm is generally applicable to any scenario where the expected signal model is parametric, offering a powerful tool for reinterpreting existing gamma-ray limits and efficiently exploring the DM parameter space in current and future indirect detection experiments.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102154"},"PeriodicalIF":6.4,"publicationDate":"2025-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415955","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}
We investigate weak gravitational lensing around black holes surrounded by perfect fluid dark matter (PFDM) in the framework of Kalb–Ramond (KR) gravity, incorporating the influence of plasma environments. Starting from the static, spherically symmetric KR–PFDM solution, we derive the null geodesic equations and formulate lensing relations in the weak deflection limit. Both homogeneous and singular isothermal sphere (SIS) plasma distributions are analyzed to assess their role in modifying the trajectory of photons due to the shift of light rays from null-geodesics. Our results demonstrate that PFDM tends to enhance the bending angle, increase the angular size of Einstein rings, and amplify image magnification, thereby strengthening the observable lensing signal. In contrast, the KR parameter suppresses these effects, reflecting the role of Lorentz-violating contributions in reducing the deflection and ring size. Plasma effects are shown to be significant and highly dependent on the adopted distribution model: uniform plasma produces the strongest deviations, whereas the SIS profile leads to more moderate corrections. The interplay between PFDM, KR gravity, and plasma introduces a degree of degeneracy, as both PFDM and plasma contribute similarly to enhancing lensing, while KR corrections diminish the overall signal. This indicates that neglecting plasma may bias interpretations of astrophysical data. By applying the theoretical framework to galactic-scale strong lensing systems, we obtain preliminary bounds on the KR and PFDM parameters. The findings highlight that weak lensing observations, particularly Einstein rings and magnification measurements, can provide a valuable means to test modified gravity theories and constrain dark matter models beyond general relativity.
{"title":"Gravitational lensing by black holes surrounded by PFDM in Kalb-Ramond gravity in plasma medium","authors":"Bekzod Rahmatov , Islom Egamberdiev , Sardor Murodov , Javlon Rayimbaev , Inomjon Ibragimov , Erkaboy Davletov , Sherzod Djumanov","doi":"10.1016/j.dark.2025.102152","DOIUrl":"10.1016/j.dark.2025.102152","url":null,"abstract":"<div><div>We investigate weak gravitational lensing around black holes surrounded by perfect fluid dark matter (PFDM) in the framework of Kalb–Ramond (KR) gravity, incorporating the influence of plasma environments. Starting from the static, spherically symmetric KR–PFDM solution, we derive the null geodesic equations and formulate lensing relations in the weak deflection limit. Both homogeneous and singular isothermal sphere (SIS) plasma distributions are analyzed to assess their role in modifying the trajectory of photons due to the shift of light rays from null-geodesics. Our results demonstrate that PFDM tends to enhance the bending angle, increase the angular size of Einstein rings, and amplify image magnification, thereby strengthening the observable lensing signal. In contrast, the KR parameter suppresses these effects, reflecting the role of Lorentz-violating contributions in reducing the deflection and ring size. Plasma effects are shown to be significant and highly dependent on the adopted distribution model: uniform plasma produces the strongest deviations, whereas the SIS profile leads to more moderate corrections. The interplay between PFDM, KR gravity, and plasma introduces a degree of degeneracy, as both PFDM and plasma contribute similarly to enhancing lensing, while KR corrections diminish the overall signal. This indicates that neglecting plasma may bias interpretations of astrophysical data. By applying the theoretical framework to galactic-scale strong lensing systems, we obtain preliminary bounds on the KR and PFDM parameters. The findings highlight that weak lensing observations, particularly Einstein rings and magnification measurements, can provide a valuable means to test modified gravity theories and constrain dark matter models beyond general relativity.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102152"},"PeriodicalIF":6.4,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415950","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 : 2025-10-27DOI: 10.1016/j.dark.2025.102150
Saeed Noori Gashti , Yassine Sekhmani , Mohammad Ali S. Afshar , Mohammad Reza Alipour , Abdul Jawad , İzzet Sakallı , B. Pourhassan , Sanjar Shaymatov , J. Sadeghi , J. Rayimbaev
This work examines the thermodynamic topology of Frolov–AdS black holes with a surrounding string fluid, highlighting the role of topological charges in determining stability. By analyzing vector fields constructed from the free energy, we identify zero points corresponding to distinct topological charges, which vary with entropy-related parameters. Our findings demonstrate that the system exhibits topological charges of 1, 0, or 1, serving as a robust criterion for black hole stability classification. Furthermore, we examine photon sphere (PS) configurations, revealing that their associated (PS = 1) reflect underlying geometric and thermodynamic structures of black hole. This study establishes connections between winding numbers and black hole phase transitions. Comparative analyses with classical black holes support the universality of the topological framework. Complementarily, the analysis of quasi-periodic oscillations elucidates the intricate interplay of electric charge, spin, cosmological constant, and string-fluid background on epicyclic and precessional motions around charged AdS black holes. Electric charge diminishes gravitational binding, shifting characteristic frequencies outward, while spin-induced frame dragging enhances orbital stability and periapsis advance. The AdS curvature associated with a negative cosmological constant universally suppresses oscillatory frequencies and modifies periastron dynamics, whereas the string-fluid parameter governs asymptotic decay rates and far-field behavior. These combined effects yield comprehensive predictions for quasinormal mode spectra and potential astrophysical signatures.
{"title":"Frolov–AdS black holes immersed in a string fluid: Harmonic oscillations, phase structure, and topological classification","authors":"Saeed Noori Gashti , Yassine Sekhmani , Mohammad Ali S. Afshar , Mohammad Reza Alipour , Abdul Jawad , İzzet Sakallı , B. Pourhassan , Sanjar Shaymatov , J. Sadeghi , J. Rayimbaev","doi":"10.1016/j.dark.2025.102150","DOIUrl":"10.1016/j.dark.2025.102150","url":null,"abstract":"<div><div>This work examines the thermodynamic topology of Frolov–AdS black holes with a surrounding string fluid, highlighting the role of topological charges in determining stability. By analyzing vector fields constructed from the free energy, we identify zero points corresponding to distinct topological charges, which vary with entropy-related parameters. Our findings demonstrate that the system exhibits topological charges of <span><math><mo>+</mo></math></span>1, 0, or <span><math><mo>−</mo></math></span>1, serving as a robust criterion for black hole stability classification. Furthermore, we examine photon sphere (PS) configurations, revealing that their associated (PS = <span><math><mo>−</mo></math></span>1) reflect underlying geometric and thermodynamic structures of black hole. This study establishes connections between winding numbers and black hole phase transitions. Comparative analyses with classical black holes support the universality of the topological framework. Complementarily, the analysis of quasi-periodic oscillations elucidates the intricate interplay of electric charge, spin, cosmological constant, and string-fluid background on epicyclic and precessional motions around charged AdS black holes. Electric charge diminishes gravitational binding, shifting characteristic frequencies outward, while spin-induced frame dragging enhances orbital stability and periapsis advance. The AdS curvature associated with a negative cosmological constant universally suppresses oscillatory frequencies and modifies periastron dynamics, whereas the string-fluid parameter governs asymptotic decay rates and far-field behavior. These combined effects yield comprehensive predictions for quasinormal mode spectra and potential astrophysical signatures.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102150"},"PeriodicalIF":6.4,"publicationDate":"2025-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415952","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 : 2025-10-24DOI: 10.1016/j.dark.2025.102142
Rounak Manna, Krishna Pada Das, Ujjal Debnath
In this work, we investigate static and spherically symmetric traversable wormhole solutions within the framework of the extended symmetric teleparallel gravity, specifically the gravity theory, where , , and are the respective representations of the non-metricity scalar, the matter Lagrangian, and the trace of the energy–momentum tensor. By employing a specific redshift function and deriving the shape function through the Karmarkar condition, we examine the fundamental geometric features required for a viable wormhole structure. The analysis confirms the satisfaction of key conditions such as the throat condition, flaring-out condition, and asymptotic flatness. A detailed study of energy conditions for various values of model parameters reveals that the null energy condition and averaged null energy condition are violated near the throat, indicating the presence of exotic matter. Additionally, thermodynamic quantities such as temperature, pressure, specific heat, work density, and energy flux are analyzed, all of which support the thermal and equilibrium stability of the wormhole. Our findings demonstrate that even in extended theories like gravity, exotic matter remains essential for sustaining traversable wormholes. This work lays the foundation for further investigations into their stability under dynamical perturbations and potential astrophysical implications.
{"title":"Possible formation of traversable wormholes and their thermodynamic analysis in F(Q,Lm,T) gravity","authors":"Rounak Manna, Krishna Pada Das, Ujjal Debnath","doi":"10.1016/j.dark.2025.102142","DOIUrl":"10.1016/j.dark.2025.102142","url":null,"abstract":"<div><div>In this work, we investigate static and spherically symmetric traversable wormhole solutions within the framework of the extended symmetric teleparallel gravity, specifically the <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity theory, where <span><math><mi>Q</mi></math></span>, <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span>, and <span><math><mi>T</mi></math></span> are the respective representations of the non-metricity scalar, the matter Lagrangian, and the trace of the energy–momentum tensor. By employing a specific redshift function and deriving the shape function through the Karmarkar condition, we examine the fundamental geometric features required for a viable wormhole structure. The analysis confirms the satisfaction of key conditions such as the throat condition, flaring-out condition, and asymptotic flatness. A detailed study of energy conditions for various values of model parameters reveals that the null energy condition and averaged null energy condition are violated near the throat, indicating the presence of exotic matter. Additionally, thermodynamic quantities such as temperature, pressure, specific heat, work density, and energy flux are analyzed, all of which support the thermal and equilibrium stability of the wormhole. Our findings demonstrate that even in extended theories like <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>m</mi></mrow></msub><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity, exotic matter remains essential for sustaining traversable wormholes. This work lays the foundation for further investigations into their stability under dynamical perturbations and potential astrophysical implications.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102142"},"PeriodicalIF":6.4,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415948","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 : 2025-10-24DOI: 10.1016/j.dark.2025.102137
Anirban Chatterjee, Yungui Gong
We investigate an interacting dark energy–dark matter model within the quintessence framework, characterized by the coupling term , and the scalar field evolves under an exponential potential , with parameters , , and . Recasting the cosmological equations into a first-order autonomous system using dimensionless variables, we perform a phase space analysis to identify conditions for stable, non-phantom accelerating attractors. The Ricci scalar term, controlled by , significantly affects the stability of critical points, with attractors transitioning to repellers for higher values of . We also analyze linear scalar perturbations, focusing on the matter density contrast and the growth index . Additionally, we compute the deceleration and jerk parameters, the Hubble rate, and the distance modulus , showing good agreement with observational data. The model naturally addresses the cosmic coincidence problem through scalar field tracking behavior. For moderate parameter values, matter perturbations continue to grow into the future, capturing both background and perturbative dynamics effectively. This framework thus offers a consistent and observationally viable approach to interacting dark energy.
我们在精粹框架下研究了一个暗能量-暗物质相互作用模型，其耦合项Q0=ακρ φ (1 - β r /(6H2))，标量场在指数势V(φ)=V0e - λκ φ下演化，参数为α、λ和β。我们使用无量纲变量将宇宙学方程重铸为一阶自治系统，并进行相空间分析，以确定稳定、非幻影加速吸引子的条件。由β控制的Ricci标量项显著影响临界点的稳定性，当β值较高时，吸引子转变为排斥子。我们还分析了线性标量扰动，重点关注物质密度对比δm和生长指数γ。此外，我们还计算了减速和跳振参数、哈勃速率和距离模量μ(z)，结果与观测数据吻合良好。该模型通过标量场跟踪行为自然地解决了宇宙巧合问题。对于中等参数值，物质扰动继续增长到未来，有效地捕获背景和摄动动力学。因此，这个框架提供了一个一致的、观测上可行的方法来研究相互作用的暗能量。
{"title":"A comprehensive dynamical and phenomenological analysis of structure growth in curvature-modulated coupled quintessence scenario","authors":"Anirban Chatterjee, Yungui Gong","doi":"10.1016/j.dark.2025.102137","DOIUrl":"10.1016/j.dark.2025.102137","url":null,"abstract":"<div><div>We investigate an interacting dark energy–dark matter model within the quintessence framework, characterized by the coupling term <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mi>α</mi><mi>κ</mi><msub><mrow><mi>ρ</mi></mrow><mrow><mi>m</mi></mrow></msub><mover><mrow><mi>ϕ</mi></mrow><mrow><mo>̇</mo></mrow></mover><mfenced><mrow><mn>1</mn><mo>−</mo><mi>β</mi><mi>R</mi><mo>/</mo><mrow><mo>(</mo><mn>6</mn><msup><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></mrow></mfenced></mrow></math></span>, and the scalar field evolves under an exponential potential <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>ϕ</mi><mo>)</mo></mrow><mo>=</mo><msub><mrow><mi>V</mi></mrow><mrow><mn>0</mn></mrow></msub><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo><mi>λ</mi><mi>κ</mi><mi>ϕ</mi></mrow></msup></mrow></math></span>, with parameters <span><math><mi>α</mi></math></span>, <span><math><mi>λ</mi></math></span>, and <span><math><mi>β</mi></math></span>. Recasting the cosmological equations into a first-order autonomous system using dimensionless variables, we perform a phase space analysis to identify conditions for stable, non-phantom accelerating attractors. The Ricci scalar term, controlled by <span><math><mi>β</mi></math></span>, significantly affects the stability of critical points, with attractors transitioning to repellers for higher values of <span><math><mi>β</mi></math></span>. We also analyze linear scalar perturbations, focusing on the matter density contrast <span><math><msub><mrow><mi>δ</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span> and the growth index <span><math><mi>γ</mi></math></span>. Additionally, we compute the deceleration and jerk parameters, the Hubble rate, and the distance modulus <span><math><mrow><mi>μ</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span>, showing good agreement with observational data. The model naturally addresses the cosmic coincidence problem through scalar field tracking behavior. For moderate parameter values, matter perturbations continue to grow into the future, capturing both background and perturbative dynamics effectively. This framework thus offers a consistent and observationally viable approach to interacting dark energy.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102137"},"PeriodicalIF":6.4,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415949","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 : 2025-10-24DOI: 10.1016/j.dark.2025.102149
Adamu Issifu , Débora P. Menezes , Tobias Frederico
This work investigates the impact of dark matter (DM) on the microscopic and macroscopic properties of proto-neutron stars (PNSs). We employ a single-fluid framework in which DM interacts with ordinary matter (OM) via the Higgs portal and remains in thermal equilibrium through non-gravitational interactions. Using a quasi-static approximation, we analyze the evolution of PNSs during the Kelvin–Helmholtz phase by varying the DM mass while keeping the entropy per baryon and lepton fraction fixed. Our results show that DM absorbs thermal energy from the stellar medium without efficient re-emission, thereby altering neutrino emission and affecting the star’s thermal evolution history. Furthermore, neutrinos contribute significantly to pressure support in the PNS phase, inhibiting DM mass accretion during neutrino-trapped stages. Based on the requirement to satisfy the observed neutron star mass constraint and to maintain consistency with supernova remnant data, we suggest an upper limit of for the DM mass that can accrete in evolving PNSs, within the model framework. In contrast, we established that cold neutron stars (NSs) can support higher DM masses without compromising equilibrium stability, owing to increased central density, enhanced gravitational binding energy, and reduced thermal pressure.
{"title":"Proto-neutron stars with dark matter admixture: A single-fluid approach","authors":"Adamu Issifu , Débora P. Menezes , Tobias Frederico","doi":"10.1016/j.dark.2025.102149","DOIUrl":"10.1016/j.dark.2025.102149","url":null,"abstract":"<div><div>This work investigates the impact of dark matter (DM) on the microscopic and macroscopic properties of proto-neutron stars (PNSs). We employ a single-fluid framework in which DM interacts with ordinary matter (OM) via the Higgs portal and remains in thermal equilibrium through non-gravitational interactions. Using a quasi-static approximation, we analyze the evolution of PNSs during the Kelvin–Helmholtz phase by varying the DM mass while keeping the entropy per baryon and lepton fraction fixed. Our results show that DM absorbs thermal energy from the stellar medium without efficient re-emission, thereby altering neutrino emission and affecting the star’s thermal evolution history. Furthermore, neutrinos contribute significantly to pressure support in the PNS phase, inhibiting DM mass accretion during neutrino-trapped stages. Based on the requirement to satisfy the observed <span><math><mrow><mn>2</mn><mspace></mspace><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></mrow></math></span> neutron star mass constraint and to maintain consistency with supernova remnant data, we suggest an upper limit of <span><math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>χ</mi></mrow></msub><mo>≤</mo><mn>0</mn><mo>.</mo><mn>62</mn><mspace></mspace><mi>GeV</mi></mrow></math></span> for the DM mass that can accrete in evolving PNSs, within the model framework. In contrast, we established that cold neutron stars (NSs) can support higher DM masses without compromising equilibrium stability, owing to increased central density, enhanced gravitational binding energy, and reduced thermal pressure.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102149"},"PeriodicalIF":6.4,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362127","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}
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