Pub Date : 2025-02-15DOI: 10.1016/j.dark.2025.101858
Guangjun Nan , I. Sabir , B. Almutairi , M.Z. Bhatti , Z. Yousaf
In this paper, we study non-static spherically symmetric shear-free anisotropic dissipative fluid distribution coupled with Maxwell field equations to find the solutions for dynamical equations Herrera et al. (2023) in gravity and use a physically realistic model, i.e., , where represents the Ricci scalar. We compute gravitational mass (Misner–Sharp) to explore matching conditions. We also construct conservation equations for ordinary, effective dark source terms and electromagnetic stress–energy tensors using Bianchi identities in gravity. Further, we utilize constraints like vanishing expansion scalar and complexity factor to derive exact analytical solutions for gravitational equations in gravity.
{"title":"Anisotropic fluid dynamics with vanishing complexity and expansion-free constraints: Exploring analytical solutions in charged modified gravity","authors":"Guangjun Nan , I. Sabir , B. Almutairi , M.Z. Bhatti , Z. Yousaf","doi":"10.1016/j.dark.2025.101858","DOIUrl":"10.1016/j.dark.2025.101858","url":null,"abstract":"<div><div>In this paper, we study non-static spherically symmetric shear-free anisotropic dissipative fluid distribution coupled with Maxwell field equations to find the solutions for dynamical equations Herrera et al. (2023) in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity and use a physically realistic model, i.e., <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>δ</mi><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>, where <span><math><mi>R</mi></math></span> represents the Ricci scalar. We compute gravitational mass (Misner–Sharp) to explore matching conditions. We also construct conservation equations for ordinary, effective dark source terms and electromagnetic stress–energy tensors using Bianchi identities in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity. Further, we utilize constraints like vanishing expansion scalar and complexity factor to derive exact analytical solutions for gravitational equations in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101858"},"PeriodicalIF":5.0,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419376","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 : 2025-02-13DOI: 10.1016/j.dark.2025.101854
Lucia A. Popa
Finding the origins of the primordial Gravitational Waves (GWs) background by the near-future Cosmic Microwave Background (CMB) polarization experiments is expected to open a new window Beyond the Standard Model (BSM) of particle physics, allowing to investigate the possible connections between the Electroweak (EW) symmetry breaking scale and the energy scale of inflation. We investigate the GWs dynamics in a set-up where the inflation sector is represented by a mixture of the SM Higgs boson and an U(1) scalar singlet field non-minimally coupled to gravity and a spectator sector represented by an U(1) axion and a SU(2) non-Abelian gauge field, assuming that there is no coupling, up to gravitational interactions, between inflation and spectator sectors.
We show that a mixture of Higgs boson with a heavy scalar singlet with large vacuum expectation value (vev) is a viable model of inflation that satisfy the existing observational data and the perturbativity constraints, avoiding in the same time the EW vacuum metastability as long as the Higgs portal interactions lead to positive tree-level threshold corrections for SM Higgs quartic coupling. We evaluate the impact of the Higgs quartic coupling threshold corrections on the GW sourced tensor modes while accounting for the consistency and backreaction constraints and show that the Higgs portal interactions enhance the GW signal sourced by the gauge field fluctuations in the CMB B-mode polarization power spectra.
We address the detectability of the GW sourced by the gauge field fluctuations in presence of Higgs portal interactions for the experimental configuration of the future CMB polarization LiteBird space mission. We find that the sourced GW tensor-to-scalar ratio in presence of Higgs portal interactions is enhanced to a level that overcomes the vacuum tensor-to-scalar ratio by a factor , much above the detection threshold of the LiteBird experiment, in agreement with the existing observational constraints on the curvature fluctuations and the allowed parameter space of Higgs portal interactions.
A large enhancement of the sourced GW can be also detected by experiments such as pulsar timing arrays and laser/atomic interferometers. Moreover, a significant Higgs–singlet mixing can be probed at LHC by the measurement of the production cross sections for Higgs-like states, while a significant tree level threshold correction of the Higgs quartic coupling can be measured at colliders by ATLAS and CMS experiments.
{"title":"Gravitational waves dynamics with Higgs portal and U(1) x SU(2) interactions","authors":"Lucia A. Popa","doi":"10.1016/j.dark.2025.101854","DOIUrl":"10.1016/j.dark.2025.101854","url":null,"abstract":"<div><div>Finding the origins of the primordial Gravitational Waves (GWs) background by the near-future Cosmic Microwave Background (CMB) polarization experiments is expected to open a new window Beyond the Standard Model (BSM) of particle physics, allowing to investigate the possible connections between the Electroweak (EW) symmetry breaking scale and the energy scale of inflation. We investigate the GWs dynamics in a set-up where the inflation sector is represented by a mixture of the SM Higgs boson and an U(1) scalar singlet field non-minimally coupled to gravity and a spectator sector represented by an U(1) axion and a SU(2) non-Abelian gauge field, assuming that there is no coupling, up to gravitational interactions, between inflation and spectator sectors.</div><div>We show that a mixture of Higgs boson with a heavy scalar singlet with large vacuum expectation value (<em>vev</em>) is a viable model of inflation that satisfy the existing observational data and the perturbativity constraints, avoiding in the same time the EW vacuum metastability as long as the Higgs portal interactions lead to positive tree-level threshold corrections for SM Higgs quartic coupling. We evaluate the impact of the Higgs quartic coupling threshold corrections on the GW sourced tensor modes while accounting for the consistency and backreaction constraints and show that the Higgs portal interactions enhance the GW signal sourced by the gauge field fluctuations in the CMB B-mode polarization power spectra.</div><div>We address the detectability of the GW sourced by the gauge field fluctuations in presence of Higgs portal interactions for the experimental configuration of the future CMB polarization LiteBird space mission. We find that the sourced GW tensor-to-scalar ratio in presence of Higgs portal interactions is enhanced to a level that overcomes the vacuum tensor-to-scalar ratio by a factor <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mn>10</mn><mo>)</mo></mrow></mrow></math></span>, much above the detection threshold of the LiteBird experiment, in agreement with the existing observational constraints on the curvature fluctuations and the allowed parameter space of Higgs portal interactions.</div><div>A large enhancement of the sourced GW can be also detected by experiments such as pulsar timing arrays and laser/atomic interferometers. Moreover, a significant Higgs–singlet mixing can be probed at LHC by the measurement of the production cross sections for Higgs-like states, while a significant tree level threshold correction of the Higgs quartic coupling can be measured at colliders by ATLAS and CMS experiments.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101854"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403086","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 : 2025-02-12DOI: 10.1016/j.dark.2025.101846
Bobomurat Ahmedov , Maria Caruana , Konstantinos F. Dialektopoulos , Jackson Levi Said , Abdurakhmon Nosirov , Zinovia Oikonomopoulou , Odil Yunusov
We present in the form of a catalogue the cosmological perturbations within the Bahamonde–Dialektopoulos–Levi Said (BDLS) theory, which serves as the teleparallel counterpart of Horndeski gravity. To understand structure formation in cosmological models, it is essential to study both the background and perturbative aspects of their cosmology. While extensive analysis of both Horndeski gravity and its teleparallel analog exists in the literature, a quantitative understanding requires a detailed examination of their cosmological perturbations. We review here all the different gauges for the scalar, vector and tensor perturbations of a cosmological background up to second order and we hope this will help people who work with observations, to incorporate it in existing codes.
{"title":"Gauge invariant perturbations in teleparallel Horndeski gravity","authors":"Bobomurat Ahmedov , Maria Caruana , Konstantinos F. Dialektopoulos , Jackson Levi Said , Abdurakhmon Nosirov , Zinovia Oikonomopoulou , Odil Yunusov","doi":"10.1016/j.dark.2025.101846","DOIUrl":"10.1016/j.dark.2025.101846","url":null,"abstract":"<div><div>We present in the form of a catalogue the cosmological perturbations within the Bahamonde–Dialektopoulos–Levi Said (BDLS) theory, which serves as the teleparallel counterpart of Horndeski gravity. To understand structure formation in cosmological models, it is essential to study both the background and perturbative aspects of their cosmology. While extensive analysis of both Horndeski gravity and its teleparallel analog exists in the literature, a quantitative understanding requires a detailed examination of their cosmological perturbations. We review here all the different gauges for the scalar, vector and tensor perturbations of a cosmological background up to second order and we hope this will help people who work with observations, to incorporate it in existing codes.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101846"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-12DOI: 10.1016/j.dark.2025.101852
Bastián Díaz Sáez
We study the thermal freeze-out of a dark photon dark matter in the so-called dark-axion portal - a triple coupling among a dark photon, an axion-like particle and the SM or boson. We analyze in detail the thermal production regimes: coscattering (aka conversion driven freeze-out), mediator freeze-out, and coannihilations. We found viable DM scenarios fulfilling the correct relic abundance in the three regimes. Apart of analyzing the parameter space for dark state masses between the GeV-TeV scale, we explore the prospects of having the axion-like field as a long-lived particle, possibly to be observed at the LHC and future detectors.
{"title":"Thermal dark photon dark matter, coscattering, and long-lived ALPs","authors":"Bastián Díaz Sáez","doi":"10.1016/j.dark.2025.101852","DOIUrl":"10.1016/j.dark.2025.101852","url":null,"abstract":"<div><div>We study the thermal freeze-out of a dark photon dark matter in the so-called <em>dark-axion portal</em> - a triple coupling among a dark photon, an axion-like particle and the SM <span><math><mi>γ</mi></math></span> or <span><math><mi>Z</mi></math></span> boson. We analyze in detail the thermal production regimes: coscattering (aka conversion driven freeze-out), mediator freeze-out, and coannihilations. We found viable DM scenarios fulfilling the correct relic abundance in the three regimes. Apart of analyzing the parameter space for dark state masses between the GeV-TeV scale, we explore the prospects of having the axion-like field as a long-lived particle, possibly to be observed at the LHC and future detectors.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101852"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419374","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}
In the current study, we have reconstructed variable modified Chaplygin gas in the Barrow holographic dark energy framework motivated by many recent studies. We have validated the generalized second law of thermodynamics for the reconstructed model. The permissible values of the reconstructed model have been determined by the recent astrophysical and cosmological observational data. The Hubble parameter is presented in terms of the observable parameters and redshift and other model parameters. From the Stern data set and joint data set of Stern with BAO and CMB observations, the bounds of the model parameters are obtained by the minimization procedure. The best-fit value of the distance modulus against redshift is obtained for the reconstructed model and it is consistent with the SNe Ia union2 sample data.
{"title":"A comprehensive analysis of Barrow holographic Chaplygin gas model reconstruction and its cosmological consequences","authors":"Sanjeeda Sultana , Chayan Ranjit , Surajit Chattopadhyay","doi":"10.1016/j.dark.2025.101843","DOIUrl":"10.1016/j.dark.2025.101843","url":null,"abstract":"<div><div>In the current study, we have reconstructed variable modified Chaplygin gas in the Barrow holographic dark energy framework motivated by many recent studies. We have validated the generalized second law of thermodynamics for the reconstructed model. The permissible values of the reconstructed model have been determined by the recent astrophysical and cosmological observational data. The Hubble parameter is presented in terms of the observable parameters and redshift <span><math><mi>z</mi></math></span> and other model parameters. From the Stern data set and joint data set of Stern with BAO and CMB observations, the bounds of the model parameters <span><math><mrow><mo>(</mo><msub><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>,</mo><msub><mrow><mi>Ω</mi></mrow><mrow><mi>b</mi><mi>h</mi><mi>d</mi><mn>0</mn></mrow></msub><mo>)</mo></mrow></math></span> are obtained by the <span><math><msup><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> minimization procedure. The best-fit value of the distance modulus <span><math><mrow><mi>μ</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> against redshift <span><math><mi>z</mi></math></span> is obtained for the reconstructed model and it is consistent with the SNe Ia union2 sample data.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101843"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419375","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}
This study aims to elucidate the nature of isotropic static spherically symmetric gravastars within the framework of braneworld gravity. Focusing on the dimensionally reduced Randall–Sundrum II scenario with positive brane tension, we utilize a physically acceptable Durgapal-V type metric potential that ensures non-singularity and stability. In alignment with the Mazur-Mottola conjecture, we derive the expressions for Durgapal-V parameters by applying junction conditions derived from a Schwarzschild vacuum, excluding a cosmological constant. Our framework envisions the inner area filled with a substance resembling an exotic energy field, while the surrounding layer is described as an ultrarelativistic stiff fluid. Through this model, we analyze multiple physical attributes of gravastars, including spatial dimensions, energy contained in the shell, entropy measurements, surface redshift due to gravitational effects, and the mass of the inner region and its thin envelope. The results provide fruitful insights into gravastars under Durgapal-V metric functions in the braneworld scenario.
{"title":"Gravastar models in braneworld scenario: The influence of Durgapal-V metric potential","authors":"Sunaiha Naeem , Arfa Waseem , Bander Almutairi , Faisal Javed","doi":"10.1016/j.dark.2025.101849","DOIUrl":"10.1016/j.dark.2025.101849","url":null,"abstract":"<div><div>This study aims to elucidate the nature of isotropic static spherically symmetric gravastars within the framework of braneworld gravity. Focusing on the dimensionally reduced Randall–Sundrum II scenario with positive brane tension, we utilize a physically acceptable Durgapal-V type metric potential that ensures non-singularity and stability. In alignment with the Mazur-Mottola conjecture, we derive the expressions for Durgapal-V parameters by applying junction conditions derived from a Schwarzschild vacuum, excluding a cosmological constant. Our framework envisions the inner area filled with a substance resembling an exotic energy field, while the surrounding layer is described as an ultrarelativistic stiff fluid. Through this model, we analyze multiple physical attributes of gravastars, including spatial dimensions, energy contained in the shell, entropy measurements, surface redshift due to gravitational effects, and the mass of the inner region and its thin envelope. The results provide fruitful insights into gravastars under Durgapal-V metric functions in the braneworld scenario.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101849"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403085","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 influence of model parameters on the orbital and epicyclic motion of test particles around a spinning Einstein-Yang–Mills-Higgs black hole. A black hole having four defining parameters is its mass , its rotation parameter , a constant, and the theory parameter . Formulas for the specific energy and angular momentum of the circular orbits in an equatorial plane are derived analytically. The stability of the spherical equatorial orbit is also examined using the effective potential method. We obtain analytical formulas for the particle frequencies of the radial, vertical, and orbital oscillations in relation to the properties of the black hole model under consideration. The main characteristics of quasi-periodic oscillations close to the stable circular orbits are discussed. Furthermore, we examine the precessions of Periastron and Lense-Thirring. It is concluded that the parameters of the consider black hole model strongly influence the motion of the particles around the black hole.
{"title":"Testing of rotating Einstein-Yang–Mills-Higgs black hole through QPOs","authors":"Asifa Ashraf , Faisal Javed , S.K. Maurya , Phongpichit Channuie , Arzu Cilli , Ertan Güdekli","doi":"10.1016/j.dark.2025.101853","DOIUrl":"10.1016/j.dark.2025.101853","url":null,"abstract":"<div><div>We investigate the influence of model parameters on the orbital and epicyclic motion of test particles around a spinning Einstein-Yang–Mills-Higgs black hole. A black hole having four defining parameters is its mass <span><math><mi>M</mi></math></span>, its rotation parameter <span><math><mi>a</mi></math></span>, a constant, <span><math><mi>β</mi></math></span> and the theory parameter <span><math><mi>B</mi></math></span>. Formulas for the specific energy and angular momentum of the circular orbits in an equatorial plane are derived analytically. The stability of the spherical equatorial orbit is also examined using the effective potential method. We obtain analytical formulas for the particle frequencies of the radial, vertical, and orbital oscillations in relation to the properties of the black hole model under consideration. The main characteristics of quasi-periodic oscillations close to the stable circular orbits are discussed. Furthermore, we examine the precessions of Periastron and Lense-Thirring. It is concluded that the parameters of the consider black hole model strongly influence the motion of the particles around the black hole.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101853"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387318","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 : 2025-02-10DOI: 10.1016/j.dark.2025.101851
M.R. Shahzad , Liaba Fakhar , H. Nazar , Asifa Ashraf , Awatef Abidi
In the present work, we proposed a new class of well-behaved charged spherical stellar models in gravity. A short review of the formulation of field equations is presented by taking the linear model of torsion function as , where is the coupling parameter of the theory, which is responsible for the deviation from the slandered General Relativity () theory and explains the matter field’s tendency to couple with geometry. To obtain a realistic solution to the established field equations we have selected a well-behaved ansatz of generalized Tolman–Kuchowicz (GTK) potential functions and the well-studied MIT bag model equation of state. As an external geometry, we include the Reissner–Nordström solution for matching conditions to identify the unknown constants resulting from the metric. The proposed model undergoes comprehensive validation to confirm its viability as a physically consistent compact object within the framework of gravity. We meticulously analyze two critical parameters: and , examining their effects on the mass, radius, and overall stability of the stellar configuration. Our investigations reveal that the model demonstrates stable behavior, devoid of singularities, and successfully accounts for a diverse array of observed compact objects in astrophysics. This thorough examination ensures that the model adheres to necessary physical criteria, reinforcing its potential applicability to understanding compact star phenomena.
{"title":"A new generic class of charged stellar structure in extended teleparallel gravity","authors":"M.R. Shahzad , Liaba Fakhar , H. Nazar , Asifa Ashraf , Awatef Abidi","doi":"10.1016/j.dark.2025.101851","DOIUrl":"10.1016/j.dark.2025.101851","url":null,"abstract":"<div><div>In the present work, we proposed a new class of well-behaved charged spherical stellar models in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity. A short review of the formulation of field equations is presented by taking the linear model of torsion function as <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>α</mi><mi>T</mi><mo>+</mo><mi>β</mi></mrow></math></span>, where <span><math><mi>α</mi></math></span> is the coupling parameter of the theory, which is responsible for the deviation from the slandered General Relativity (<span><math><mrow><mi>G</mi><mi>R</mi></mrow></math></span>) theory and explains the matter field’s tendency to couple with geometry. To obtain a realistic solution to the established field equations we have selected a well-behaved ansatz of generalized Tolman–Kuchowicz (GTK) potential functions and the well-studied MIT bag model equation of state. As an external geometry, we include the Reissner–Nordström solution for matching conditions to identify the unknown constants resulting from the <span><math><mrow><mi>G</mi><mi>T</mi><mi>K</mi></mrow></math></span> metric. The proposed model undergoes comprehensive validation to confirm its viability as a physically consistent compact object within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity. We meticulously analyze two critical parameters: <span><math><mi>α</mi></math></span> and <span><math><mi>n</mi></math></span>, examining their effects on the mass, radius, and overall stability of the stellar configuration. Our investigations reveal that the model demonstrates stable behavior, devoid of singularities, and successfully accounts for a diverse array of observed compact objects in astrophysics. This thorough examination ensures that the model adheres to necessary physical criteria, reinforcing its potential applicability to understanding compact star phenomena.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101851"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387317","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 : 2025-02-06DOI: 10.1016/j.dark.2025.101842
A.D. Alruwaili , N. Azhar , A. Jawad , A.B. Albarrak
In this research, we investigate the phenomenon of gravitational baryogenesis and generalized gravitational baryogenesis within the framework of gravity where expresses the non-metricity scalar and is the boundary term. To explore this mechanism, we utilize four distinct minimal and non-minimal models and analyze the evolution of the baryon to entropy ratio in relation to a scale factor in the form of a power-law ( , where and are nonzero constants). By studying the CP-violating interaction terms and , we derive expressions for the baryon asymmetry and examine its behavior across different cosmological epochs. The results obtained from all four models demonstrate compatibility with current observational data on baryon asymmetry, suggesting that gravity offer a robust explanation for the matter–antimatter imbalance in the universe. Our findings reinforce the potential of this modified gravity theory to extend the understanding of baryogenesis beyond the scope of standard models, offering new insights into early universe cosmology and the mechanisms driving the generation of baryon asymmetry.
{"title":"Probing gravitational baryogenesis phenomenon in specific modified gravity","authors":"A.D. Alruwaili , N. Azhar , A. Jawad , A.B. Albarrak","doi":"10.1016/j.dark.2025.101842","DOIUrl":"10.1016/j.dark.2025.101842","url":null,"abstract":"<div><div>In this research, we investigate the phenomenon of gravitational baryogenesis and generalized gravitational baryogenesis within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>B</mi><mo>)</mo></mrow></mrow></math></span> gravity where <span><math><mi>Q</mi></math></span> expresses the non-metricity scalar and <span><math><mi>B</mi></math></span> is the boundary term. To explore this mechanism, we utilize four distinct minimal and non-minimal <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>B</mi><mo>)</mo></mrow></mrow></math></span> models and analyze the evolution of the baryon to entropy ratio in relation to a scale factor in the form of a power-law ( <span><math><mrow><mi>a</mi><mo>=</mo><mi>Υ</mi><mspace></mspace><msup><mrow><mi>t</mi></mrow><mrow><mi>γ</mi></mrow></msup></mrow></math></span>, where <span><math><mi>Υ</mi></math></span> and <span><math><mi>γ</mi></math></span> are nonzero constants). By studying the CP-violating interaction terms <span><math><mrow><msub><mrow><mi>∂</mi></mrow><mrow><mi>μ</mi></mrow></msub><mrow><mo>(</mo><mi>Q</mi><mo>+</mo><mi>B</mi><mo>)</mo></mrow></mrow></math></span> and <span><math><mrow><msub><mrow><mi>∂</mi></mrow><mrow><mi>μ</mi></mrow></msub><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>+</mo><mi>B</mi><mo>)</mo></mrow></mrow></math></span>, we derive expressions for the baryon asymmetry and examine its behavior across different cosmological epochs. The results obtained from all four models demonstrate compatibility with current observational data on baryon asymmetry, suggesting that <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>B</mi><mo>)</mo></mrow></mrow></math></span> gravity offer a robust explanation for the matter–antimatter imbalance in the universe. Our findings reinforce the potential of this modified gravity theory to extend the understanding of baryogenesis beyond the scope of standard models, offering new insights into early universe cosmology and the mechanisms driving the generation of baryon asymmetry.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"48 ","pages":"Article 101842"},"PeriodicalIF":5.0,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143369841","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 : 2025-02-05DOI: 10.1016/j.dark.2025.101841
M. Yousaf, H. Asad
In this study, the possibility of constructing wormhole geometries is explored within the framework of gravity, where is Ricci scalar and represents the trace of the energy–momentum tensor. We employ the Visser cut-and-paste technique to construct thin-shell wormholes by joining two identical copies of the Reissner-Nordström (RN) spacetime which allows the formulation of wormhole geometries by introducing a throat, the boundary of the two spacetime copies, where the stress–energy tensor components are determined using the Lanczos equations. To derive wormhole solutions, our analyses focus on a static, spherically symmetric spacetime and incorporate the modified Chaplygin gas (MCG) equation of state (EoS) as a source of exotic matter. The dynamical equation governing the system is examined under the assumption of small linear perturbations around a static equilibrium state within an isotropic background which is critical in assessing the stability of the wormhole configurations. We present our findings theoretically and graphically, highlighting the behavior of wormhole solutions for various parametric choices of the model and the EoS. The results indicate that distinct parameters set yield stable and unstable wormhole solutions, demonstrating the feasibility of maintaining traversable wormhole geometries in this modified gravity framework. Our considered minimally coupling gravity model supports a variety of wormhole configurations, some of which can achieve stability under linear perturbations. These findings contribute to the broader understanding of exotic structures in modified theories of gravity and their astrophysical implications.
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