Pub Date : 2025-10-14DOI: 10.1016/j.dark.2025.102134
Daniele Perri , Michele Doro , Takeshi Kobayashi
Magnetic monopoles with masses up to GeV can be accelerated to relativistic velocities in Galactic and intergalactic magnetic fields. The cosmic flux of relativistic monopoles is constrained by various experiments, with the limits given as functions of the monopole velocity (Lorentz factor) at the detectors. The velocity, however, is usually treated as a free parameter due to the ambiguity in the computation of the acceleration before the monopoles arrive at Earth. We explicitly evaluate the velocity by exploiting recent studies on cosmic magnetic fields and the monopole acceleration therein, to recast experimental limits in terms of the mass of monopoles. By applying our method to various terrestrial experiments, including the Pierre Auger Observatory, IceCube, MACRO, and the upcoming Cherenkov Telescope Array Observatory, as well as to astrophysical constraints, we report limits on the flux of monopoles for a wide range of monopole masses. We also highlight the role of monopoles as messengers of cosmic magnetic fields, and discuss the possibility of using monopole experiments to probe intergalactic magnetic fields.
{"title":"Recasting experimental constraints on relativistic magnetic monopoles","authors":"Daniele Perri , Michele Doro , Takeshi Kobayashi","doi":"10.1016/j.dark.2025.102134","DOIUrl":"10.1016/j.dark.2025.102134","url":null,"abstract":"<div><div>Magnetic monopoles with masses up to <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>14</mn></mrow></msup></mrow></math></span> GeV can be accelerated to relativistic velocities in Galactic and intergalactic magnetic fields. The cosmic flux of relativistic monopoles is constrained by various experiments, with the limits given as functions of the monopole velocity (Lorentz factor) at the detectors. The velocity, however, is usually treated as a free parameter due to the ambiguity in the computation of the acceleration before the monopoles arrive at Earth. We explicitly evaluate the velocity by exploiting recent studies on cosmic magnetic fields and the monopole acceleration therein, to recast experimental limits in terms of the mass of monopoles. By applying our method to various terrestrial experiments, including the Pierre Auger Observatory, IceCube, MACRO, and the upcoming Cherenkov Telescope Array Observatory, as well as to astrophysical constraints, we report limits on the flux of monopoles for a wide range of monopole masses. We also highlight the role of monopoles as messengers of cosmic magnetic fields, and discuss the possibility of using monopole experiments to probe intergalactic magnetic fields.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102134"},"PeriodicalIF":6.4,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320525","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 the motion of spinning charged test particles in the Schwarzschild-MOG black hole background immersed in an asymptotically uniform magnetic field. Using the Mathisson–Papapetrou–Dixon equations (MPD) under the supplementary Tulczyjew spin condition, we derive the equations governing equatorial circular motion and examine the combined effects of spin-curvature, magnetic and MOG field interactions with charged particles, contribution of MOG field in magnetic fields near the black hole and also separately the gravitational effects of the MOG field on the particle dynamics. The superluminal constraints are analyzed to identify the physically admissible range for the spin and MOG field magnitude. Furthermore, we construct the effective potential and explore how spin and magnetic coupling, together with MOG modifications to gravity, influence orbital features such as the shift in the innermost stable circular orbit (ISCO). Our findings provide a detailed characterization of the dynamics of spinning charged particles in a magnetized Schwarzschild-MOG geometry and highlight deviations from the predictions of general relativity (GR). Finally, we consider collisions of spinning-charged particles near the black hole horizon and collisions at ISCOs. Our graphical results have shown that magnetic and MOG interactions contribute to the center-of-mass energy of spinning-charged particles at ISCOs.
{"title":"Collisions and circular motion of spinning-charged particle around magnetized black holes in modified gravity","authors":"Tursinbay Oteev , Javlon Rayimbaev , Bobomurat Ahmedov , Inomjon Ibragimov , Murodbek Vapayev , Sokhibjan Muminov","doi":"10.1016/j.dark.2025.102118","DOIUrl":"10.1016/j.dark.2025.102118","url":null,"abstract":"<div><div>We investigate the motion of spinning charged test particles in the Schwarzschild-MOG black hole background immersed in an asymptotically uniform magnetic field. Using the Mathisson–Papapetrou–Dixon equations (MPD) under the supplementary Tulczyjew spin condition, we derive the equations governing equatorial circular motion and examine the combined effects of spin-curvature, magnetic and MOG field interactions with charged particles, contribution of MOG field in magnetic fields near the black hole and also separately the gravitational effects of the MOG field on the particle dynamics. The superluminal constraints are analyzed to identify the physically admissible range for the spin and MOG field magnitude. Furthermore, we construct the effective potential and explore how spin and magnetic coupling, together with MOG modifications to gravity, influence orbital features such as the shift in the innermost stable circular orbit (ISCO). Our findings provide a detailed characterization of the dynamics of spinning charged particles in a magnetized Schwarzschild-MOG geometry and highlight deviations from the predictions of general relativity (GR). Finally, we consider collisions of spinning-charged particles near the black hole horizon and collisions at ISCOs. Our graphical results have shown that magnetic and MOG interactions contribute to the center-of-mass energy of spinning-charged particles at ISCOs.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102118"},"PeriodicalIF":6.4,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320468","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 : 2025-10-13DOI: 10.1016/j.dark.2025.102119
Marcel van der Westhuizen , Amare Abebe , Eleonora Di Valentino
<div><div>Interacting dark energy (IDE) models, in which dark matter (DM) and dark energy (DE) exchange energy through a non-gravitational interaction, have long been proposed as candidates to address key challenges in modern cosmology. These include the coincidence problem, the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>8</mn></mrow></msub></math></span> tensions, and, more recently, the hints of dynamical dark energy reported by the DESI collaboration. Given the renewed interest in IDE models, it is crucial to fully understand their parameter space when constraining them observationally, especially with regard to the often-neglected issues of negative energy densities and future big rip singularities. In this work, we present a comparative study of the general linear interaction <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mrow><mo>(</mo><msub><mrow><mi>δ</mi></mrow><mrow><mi>dm</mi></mrow></msub><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>δ</mi></mrow><mrow><mi>de</mi></mrow></msub><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> and four special cases: <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mrow><mo>(</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mrow><mo>(</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>−</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub></mrow></math></span>, and <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></math></span>. For these five models, we perform a dynamical system analysis and derive new conditions that ensure positive, real, and well-defined energy densities throughout cosmic evolution, as well as criteria to avoid future big rip singularities. We obtain exact analytical solutions for <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub></math></span>, <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></math></span>, the effective equations of state (<span><math><msubsup><mrow><mi>w</mi></mrow><mrow><mi>eff</mi></mrow><mrow><mi>dm</mi></mrow></msubsup></math></span>, <span><math><msubsup><mrow><mi>w</mi></mrow><mrow><mi>eff</mi></mrow><mrow><mi>de</mi></mrow></msubsup></math></span>, <span><math><msubsup><mrow><mi>w</mi></mrow><mrow><mi>eff</mi></mrow><mrow><mi>tot</mi></mrow></msubsup></math></span>), and a reconstructed dynamical DE equation of state <span><mat
{"title":"I. Linear interacting dark energy: Analytical solutions and theoretical pathologies","authors":"Marcel van der Westhuizen , Amare Abebe , Eleonora Di Valentino","doi":"10.1016/j.dark.2025.102119","DOIUrl":"10.1016/j.dark.2025.102119","url":null,"abstract":"<div><div>Interacting dark energy (IDE) models, in which dark matter (DM) and dark energy (DE) exchange energy through a non-gravitational interaction, have long been proposed as candidates to address key challenges in modern cosmology. These include the coincidence problem, the <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>8</mn></mrow></msub></math></span> tensions, and, more recently, the hints of dynamical dark energy reported by the DESI collaboration. Given the renewed interest in IDE models, it is crucial to fully understand their parameter space when constraining them observationally, especially with regard to the often-neglected issues of negative energy densities and future big rip singularities. In this work, we present a comparative study of the general linear interaction <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mrow><mo>(</mo><msub><mrow><mi>δ</mi></mrow><mrow><mi>dm</mi></mrow></msub><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>δ</mi></mrow><mrow><mi>de</mi></mrow></msub><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> and four special cases: <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mrow><mo>(</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mrow><mo>(</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>−</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub></mrow></math></span>, and <span><math><mrow><mi>Q</mi><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></math></span>. For these five models, we perform a dynamical system analysis and derive new conditions that ensure positive, real, and well-defined energy densities throughout cosmic evolution, as well as criteria to avoid future big rip singularities. We obtain exact analytical solutions for <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub></math></span>, <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></math></span>, the effective equations of state (<span><math><msubsup><mrow><mi>w</mi></mrow><mrow><mi>eff</mi></mrow><mrow><mi>dm</mi></mrow></msubsup></math></span>, <span><math><msubsup><mrow><mi>w</mi></mrow><mrow><mi>eff</mi></mrow><mrow><mi>de</mi></mrow></msubsup></math></span>, <span><math><msubsup><mrow><mi>w</mi></mrow><mrow><mi>eff</mi></mrow><mrow><mi>tot</mi></mrow></msubsup></math></span>), and a reconstructed dynamical DE equation of state <span><mat","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102119"},"PeriodicalIF":6.4,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320466","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 : 2025-10-13DOI: 10.1016/j.dark.2025.102132
Phongsakorn Sereewat, David Senjaya
This work reports a novel investigation of the bulk and CFT thermodynamics of Kerr–EMDA–AdS black hole in 3+1-dimensional AdS spacetime. We comprehensively present the construction of mass functions, the enthalpy analog, of the black hole for both scenarios and derive thermodynamic quantities from there. In the first part of this work, we derive an analytical expression of the bulk temperature, angular momentum per unit mass, electric field, thermodynamic volume, Gibbs and Helmholtz’s free energy functions, internal energy, specific heat capacities, adiabatic compressibility and the thermodynamic black hole’s speed of sound analog. The critical point of the analog Van der Waals phase transition is also analytically investigated. The second part of this work focuses on the CFT thermodynamics counterpart, especially on the critical phenomena. The behavior of the temperature, Helmholtz’s free energy and the heat capacity are analytically and graphically explored in various thermodynamical aspects. The last part of this work is dedicated to investigate the critical phenomena in and frameworks via implicit method. Interestingly, we also find that the Kerr–EMDA–AdS black hole exhibits not only first-order phase transitions in the dual CFT, but also a reentrant phase transition, characterized by a multibranched structure of the heat capacity.
{"title":"Holographic thermodynamics of Kerr–Einstein–Maxwell–dilaton–axion–Anti-de-Sitter black hole","authors":"Phongsakorn Sereewat, David Senjaya","doi":"10.1016/j.dark.2025.102132","DOIUrl":"10.1016/j.dark.2025.102132","url":null,"abstract":"<div><div>This work reports a novel investigation of the bulk and CFT thermodynamics of Kerr–EMDA–AdS black hole in 3+1-dimensional AdS spacetime. We comprehensively present the construction of mass functions, the enthalpy analog, of the black hole for both scenarios and derive thermodynamic quantities from there. In the first part of this work, we derive an analytical expression of the bulk temperature, angular momentum per unit mass, electric field, thermodynamic volume, Gibbs and Helmholtz’s free energy functions, internal energy, specific heat capacities, adiabatic compressibility and the thermodynamic black hole’s speed of sound analog. The critical point of the analog Van der Waals phase transition is also analytically investigated. The second part of this work focuses on the CFT thermodynamics counterpart, especially on the critical phenomena. The behavior of the temperature, Helmholtz’s free energy and the heat capacity are analytically and graphically explored in various thermodynamical aspects. The last part of this work is dedicated to investigate the critical phenomena in <span><math><mrow><mover><mrow><mi>F</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>−</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover></mrow></math></span> and <span><math><mrow><mover><mrow><mi>G</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>−</mo><mover><mrow><mi>T</mi></mrow><mrow><mo>̄</mo></mrow></mover></mrow></math></span> frameworks via implicit method. Interestingly, we also find that the Kerr–EMDA–AdS black hole exhibits not only first-order phase transitions in the dual CFT, but also a reentrant phase transition, characterized by a multibranched structure of the heat capacity.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102132"},"PeriodicalIF":6.4,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320529","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 : 2025-10-11DOI: 10.1016/j.dark.2025.102130
Abdelhakim Benkrane
In this work, we derive the entropy of dark matter halos described by double (broken) power-law density profiles, motivated by Verlinde’s view of gravity as an emergent entropic phenomenon. We consider four halo models – the Dehnen-type, Hernquist, Jaffe, and Plummer spheres – along with the perfect sphere, deriving their entropy expressions and testing consistency with the second law of thermodynamics. All models, except the perfect sphere, satisfy the second law. We further extend the analysis to a cosmological framework, examining how these entropy forms affect the Friedmann equations. By plotting the energy density against the central halo radius , we find that increasing decreases the energy density.
{"title":"Entropy analysis of dark matter halo structures","authors":"Abdelhakim Benkrane","doi":"10.1016/j.dark.2025.102130","DOIUrl":"10.1016/j.dark.2025.102130","url":null,"abstract":"<div><div>In this work, we derive the entropy of dark matter halos described by double (broken) power-law density profiles, motivated by Verlinde’s view of gravity as an emergent entropic phenomenon. We consider four halo models – the Dehnen-type, Hernquist, Jaffe, and Plummer spheres – along with the perfect sphere, deriving their entropy expressions and testing consistency with the second law of thermodynamics. All models, except the perfect sphere, satisfy the second law. We further extend the analysis to a cosmological framework, examining how these entropy forms affect the Friedmann equations. By plotting the energy density against the central halo radius <span><math><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, we find that increasing <span><math><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> decreases the energy density.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102130"},"PeriodicalIF":6.4,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320465","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 : 2025-10-11DOI: 10.1016/j.dark.2025.102128
Muhammad Yasir , Tong Lining , Kazuharu Bamba
Exact black holes in the Einstein Euler-Heisenberg theory are explored with an exponential entropy framework by using the topological current -mapping theory. The topology classes are investigated through the canonical, mixed, and grand canonical ensembles. In particular, the magnetic charge is fixed for the canonical ensemble, whereas the magnetic potential is included for the mixed ensemble and the grand canonical ensemble with maintaining its consistency through the magnetic potential. The topological charges are analyzed for each ensemble through critical points. As a result, it is found that the canonical, mixed, and grand canonical ensembles lead to either 1, , or no generation/annihilation points. Moreover, it is shown how temperature and heat capacity depend on the horizon radius in order to verify the stability of a black hole. Furthermore, the behavior of the thermodynamic curvatures of a black hole is investigated through the geometric methods.
{"title":"Differential topology and micro-structure of black hole in Einstein–Euler–Heisenberg spacetimes with exponential entropy","authors":"Muhammad Yasir , Tong Lining , Kazuharu Bamba","doi":"10.1016/j.dark.2025.102128","DOIUrl":"10.1016/j.dark.2025.102128","url":null,"abstract":"<div><div>Exact black holes in the Einstein Euler-Heisenberg theory are explored with an exponential entropy framework by using the topological current <span><math><mi>Ψ</mi></math></span>-mapping theory. The topology classes are investigated through the canonical, mixed, and grand canonical ensembles. In particular, the magnetic charge is fixed for the canonical ensemble, whereas the magnetic potential is included for the mixed ensemble and the grand canonical ensemble with maintaining its consistency through the magnetic potential. The topological charges are analyzed for each ensemble through critical points. As a result, it is found that the canonical, mixed, and grand canonical ensembles lead to either 1, <span><math><mrow><mo>−</mo><mn>1</mn></mrow></math></span>, or no generation/annihilation points. Moreover, it is shown how temperature and heat capacity depend on the horizon radius in order to verify the stability of a black hole. Furthermore, the behavior of the thermodynamic curvatures of a black hole is investigated through the geometric methods.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102128"},"PeriodicalIF":6.4,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320463","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 : 2025-10-11DOI: 10.1016/j.dark.2025.102131
Rishab Singha, Ashutosh Singh
In this paper, we analyze the Generalized Brans–Dicke (GBD) cosmological model to describe the varying dark energy evolution in the homogeneous and isotropic background. The dynamical scalar field is non-minimally coupled to gravity. The influence of scalar field on the universe’s expansion has been studied wherein the coupling parameter determines the direction and magnitude of the energy transfer between matter and scalar field. In order to compare the model against observations, we perform a joint statistical analysis with the independent cosmological data sets composed of the Cosmic Chronometer (CC) data, DESI BAO, CMB and the Pantheon+SH0ES data. We adopt the Bayesian statistical analysis by using the Markov Chain Monte Carlo (MCMC) technique to constrain the model parameters. The observational constraint on indicates a substantial deviation from the General Relativity model and the corresponding constraint describes the energy transfer from the scalar field into matter. A deeper examination of cosmographic quantities indicates that the present model fits well with the late-time observations. We also discuss the issue of Hubble tension in contrast to the different models of gravity. We further analyze the model selection criterion in contrast to the CDM model.
{"title":"Non-minimally coupled scalar field model: Late-time constraints and the H0 tension","authors":"Rishab Singha, Ashutosh Singh","doi":"10.1016/j.dark.2025.102131","DOIUrl":"10.1016/j.dark.2025.102131","url":null,"abstract":"<div><div>In this paper, we analyze the Generalized Brans–Dicke (GBD) cosmological model to describe the varying dark energy evolution in the homogeneous and isotropic background. The dynamical scalar field is non-minimally coupled to gravity. The influence of scalar field on the universe’s expansion has been studied wherein the coupling parameter <span><math><mi>ɛ</mi></math></span> determines the direction and magnitude of the energy transfer between matter and scalar field. In order to compare the model against observations, we perform a joint statistical analysis with the independent cosmological data sets composed of the Cosmic Chronometer (CC) data, DESI BAO, CMB and the Pantheon+SH0ES data. We adopt the Bayesian statistical analysis by using the Markov Chain Monte Carlo (MCMC) technique to constrain the model parameters. The observational constraint on <span><math><mi>ɛ</mi></math></span> indicates a substantial deviation from the General Relativity model and the corresponding constraint describes the energy transfer from the scalar field into matter. A deeper examination of cosmographic quantities indicates that the present model fits well with the late-time observations. We also discuss the issue of Hubble tension in contrast to the different models of gravity. We further analyze the model selection criterion in contrast to the <span><math><mi>Λ</mi></math></span>CDM model.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102131"},"PeriodicalIF":6.4,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320523","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 : 2025-10-10DOI: 10.1016/j.dark.2025.102126
Matteo Forconi , Alessandro Melchiorri
The detection of non-Gaussianities (NG) in the Cosmic Microwave Background (CMB) is essential to better understand the early epochs of our Universe. One way to observe NG is to constrain the bispectrum, which usually is the largest non-trivial correlation function for most of the inflationary models. However, natural NG arise from late-time evolution and they need to be subtracted from the signal. In this work, we investigate the impact of different dark energy models to the bias induced by the cross-correlation between the Integrated Sachs–Wolfe effect and the weak lensing. More specifically, we compute the predictions for models of dynamical dark energy, and CPL parametrization, as well as different realizations of the sign-switching cosmological constant model.
{"title":"The impact on non-Gaussianities of the ISW-Lensing correlation in non-standard cosmologies","authors":"Matteo Forconi , Alessandro Melchiorri","doi":"10.1016/j.dark.2025.102126","DOIUrl":"10.1016/j.dark.2025.102126","url":null,"abstract":"<div><div>The detection of non-Gaussianities (NG) in the Cosmic Microwave Background (CMB) is essential to better understand the early epochs of our Universe. One way to observe NG is to constrain the bispectrum, which usually is the largest non-trivial correlation function for most of the inflationary models. However, natural NG arise from late-time evolution and they need to be subtracted from the signal. In this work, we investigate the impact of different dark energy models to the bias induced by the cross-correlation between the Integrated Sachs–Wolfe effect and the weak lensing. More specifically, we compute the predictions for models of dynamical dark energy, <span><math><mrow><mi>w</mi><mo>≠</mo><mo>−</mo><mn>1</mn></mrow></math></span> and CPL parametrization, as well as different realizations of the sign-switching cosmological constant model.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102126"},"PeriodicalIF":6.4,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266299","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 : 2025-10-10DOI: 10.1016/j.dark.2025.102120
Marcel van der Westhuizen , Amare Abebe , Eleonora Di Valentino
<div><div>We investigate interacting dark energy (IDE) models with phenomenological, non-linear interaction kernels <span><math><mi>Q</mi></math></span>, specifically <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mfenced><mrow><mfrac><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></mfrac></mrow></mfenced></mrow></math></span>, <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mfenced><mrow><mfrac><mrow><msubsup><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow><mrow><mn>2</mn></mrow></msubsup></mrow><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></mfrac></mrow></mfenced></mrow></math></span>, and <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mfenced><mrow><mfrac><mrow><msubsup><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow><mrow><mn>2</mn></mrow></msubsup></mrow><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></mfrac></mrow></mfenced></mrow></math></span>. Using dynamical system techniques developed in our companion paper on linear kernels, we derive new conditions that ensure positive and well-defined energy densities, as well as criteria to avoid future big rip singularities. We find that for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>, all densities remain positive, while for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> negative values of either DM or DE are unavoidable if energy flows from DM to DE. We also show that for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> a big rip singularity always arises in the phantom regime <span><math><mrow><mi>w</mi><mo><</mo><mo>−</mo><mn>1</mn></mrow></math></span>, whereas for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> this fate may be avoided if energy flows from DE to DM. In addition, we provide new exact analytical solutions for <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></math></span> in the cases of <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>Q</mi></
我们研究了具有现象学非线性相互作用核Q的相互作用暗能量（IDE）模型，具体来说，Q1= 3h δρdmρ dem +ρde, Q2=3Hδρdm2ρdm+ρde, Q3=3Hδρde2ρdm+ρde。利用我们在线性核的同伴论文中开发的动力系统技术，我们推导了确保正的和定义良好的能量密度的新条件，以及避免未来大撕裂奇点的准则。我们发现Q1,所有密度保持积极,而对于Q2和Q3负的DM或德如果能量从DM DE流动是不可避免的。我们还表明,奇点总是出现在Q1和Q2一道裂口幻影政权w<−1,而对于第三季度这种命运可能避免如果能源来自DE DM。此外,我们提供新的精确解析解的ρDM和ρDE Q2和Q3,并获得新的DM的有效状态方程表达式,德,总流体，以及重构的动力学DE状态方程（wdmeff、wdeff、wtoteff和w_）。使用这些结果，我们讨论虚交叉，评估每个内核如何解决一致性问题，并应用状态查找器诊断来比较模型。这些发现扩展了对非线性IDE模型的理论理解，并为未来的观测约束提供了分析工具。
{"title":"II. Non-linear interacting dark energy: Analytical solutions and theoretical pathologies","authors":"Marcel van der Westhuizen , Amare Abebe , Eleonora Di Valentino","doi":"10.1016/j.dark.2025.102120","DOIUrl":"10.1016/j.dark.2025.102120","url":null,"abstract":"<div><div>We investigate interacting dark energy (IDE) models with phenomenological, non-linear interaction kernels <span><math><mi>Q</mi></math></span>, specifically <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mfenced><mrow><mfrac><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></mfrac></mrow></mfenced></mrow></math></span>, <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mfenced><mrow><mfrac><mrow><msubsup><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow><mrow><mn>2</mn></mrow></msubsup></mrow><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></mfrac></mrow></mfenced></mrow></math></span>, and <span><math><mrow><msub><mrow><mi>Q</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>3</mn><mi>H</mi><mi>δ</mi><mfenced><mrow><mfrac><mrow><msubsup><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow><mrow><mn>2</mn></mrow></msubsup></mrow><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub><mo>+</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></mrow></mfrac></mrow></mfenced></mrow></math></span>. Using dynamical system techniques developed in our companion paper on linear kernels, we derive new conditions that ensure positive and well-defined energy densities, as well as criteria to avoid future big rip singularities. We find that for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>, all densities remain positive, while for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> negative values of either DM or DE are unavoidable if energy flows from DM to DE. We also show that for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> a big rip singularity always arises in the phantom regime <span><math><mrow><mi>w</mi><mo><</mo><mo>−</mo><mn>1</mn></mrow></math></span>, whereas for <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> this fate may be avoided if energy flows from DE to DM. In addition, we provide new exact analytical solutions for <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>dm</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>ρ</mi></mrow><mrow><mi>de</mi></mrow></msub></math></span> in the cases of <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>Q</mi></","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102120"},"PeriodicalIF":6.4,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362134","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 : 2025-10-10DOI: 10.1016/j.dark.2025.102129
Mariam Bouhmadi-López , Beñat Ibarra-Uriondo
In this work, we carry out a comprehensive perturbative analysis of four cosmological models featuring a sign-switching cosmological constant. Among these, we include the well-known CDM model, characterised by an abrupt transition from a negative to a positive cosmological constant. We also consider the LCDM model, which exhibits a generalised ladder-step evolution, as well as the SSCDM and ECDM models, both of which undergo a smooth sign change at comparable redshifts. We solve the linear cosmological perturbation equations from the radiation-dominated era, imposing initial adiabatic conditions for matter and radiation, for modes well outside the Hubble radius in the early Universe. We analyse the behaviour of the matter density contrast, the gravitational potential, the linear growth rate, the matter power spectrum, and the evolution . These results are contrasted with predictions from the standard CDM model and are confronted with observational data.
{"title":"Cosmological perturbations for smooth sign-switching dark energy models","authors":"Mariam Bouhmadi-López , Beñat Ibarra-Uriondo","doi":"10.1016/j.dark.2025.102129","DOIUrl":"10.1016/j.dark.2025.102129","url":null,"abstract":"<div><div>In this work, we carry out a comprehensive perturbative analysis of four cosmological models featuring a sign-switching cosmological constant. Among these, we include the well-known <span><math><msub><mrow><mi>Λ</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>CDM model, characterised by an abrupt transition from a negative to a positive cosmological constant. We also consider the L<span><math><mi>Λ</mi></math></span>CDM model, which exhibits a generalised ladder-step evolution, as well as the SSCDM and ECDM models, both of which undergo a smooth sign change at comparable redshifts. We solve the linear cosmological perturbation equations from the radiation-dominated era, imposing initial adiabatic conditions for matter and radiation, for modes well outside the Hubble radius in the early Universe. We analyse the behaviour of the matter density contrast, the gravitational potential, the linear growth rate, the matter power spectrum, and the <span><math><mrow><mi>f</mi><msub><mrow><mi>σ</mi></mrow><mrow><mn>8</mn></mrow></msub></mrow></math></span> evolution . These results are contrasted with predictions from the standard <span><math><mi>Λ</mi></math></span>CDM model and are confronted with observational data.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"50 ","pages":"Article 102129"},"PeriodicalIF":6.4,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145320528","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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