Pub Date : 2025-02-01DOI: 10.1016/j.dark.2024.101755
Chandra Rekha Mahanta, Dibyajyoti Das
In this paper, we investigate a spatially homogeneous and anisotropic Bianchi type-I universe filled with cold dark matter and Tsallis holographic dark energy within the framework of General Relativity. We assume the cold dark matter and the Tsallis holographic dark energy to be non-interacting and obtain exact solutions of the Einstein field equations by considering a linearly varying deceleration parameter. The physical and kinematical properties of the resulting model are explored through different parameters of cosmological importance such as the Hubble parameter, the anisotropy parameter, the equation of state parameter, the jerk parameter, the snap parameter, the lerk parameter etc. The validation or violation of the four energy conditions are also checked. We find that the Weak and Dominant Energy Conditions are fulfilled but the Null and Strong Energy Conditions are violated at late time which supports the accelerated expansion of the universe. In addition, we establish the correspondence between phantom scalar field model and Tsallis holographic dark energy model.
{"title":"Tsallis holographic dark energy model in an anisotropic universe with linearly varying deceleration parameter and its correspondence with phantom","authors":"Chandra Rekha Mahanta, Dibyajyoti Das","doi":"10.1016/j.dark.2024.101755","DOIUrl":"10.1016/j.dark.2024.101755","url":null,"abstract":"<div><div>In this paper, we investigate a spatially homogeneous and anisotropic Bianchi type-I universe filled with cold dark matter and Tsallis holographic dark energy within the framework of General Relativity. We assume the cold dark matter and the Tsallis holographic dark energy to be non-interacting and obtain exact solutions of the Einstein field equations by considering a linearly varying deceleration parameter. The physical and kinematical properties of the resulting model are explored through different parameters of cosmological importance such as the Hubble parameter, the anisotropy parameter, the equation of state parameter, the jerk parameter, the snap parameter, the lerk parameter etc. The validation or violation of the four energy conditions are also checked. We find that the Weak and Dominant Energy Conditions are fulfilled but the Null and Strong Energy Conditions are violated at late time which supports the accelerated expansion of the universe. In addition, we establish the correspondence between phantom scalar field model and Tsallis holographic dark energy model.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101755"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100012","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 : 2025-02-01DOI: 10.1016/j.dark.2024.101756
Hauke Fischer, Christian Käding, Mario Pitschmann
Light scalar fields play a variety of roles in modern physics, especially in cosmology and modified theories of gravity. For this reason, there is a zoo of experiments actively trying to find evidence for many scalar field models that have been proposed in theoretical considerations. Among those are setups in which the pressures expected to be induced by light scalar fields between two parallel plates are studied, for example, Casimir force experiments. While it is known that classical and quantum pressures caused by light scalar fields could have significant impacts on such experiments, in this article, we show that this can also be the case for thermal pressure. More specifically, we derive expressions for the quantum and thermal pressures induced by exchanges of light scalar field fluctuations between two thin parallel plates. As particular examples, we then look at screened scalar fields. For chameleon, symmetron and environment-dependent dilaton models, we find large regions in their parameter spaces that allow for thermal pressures to equal or exceed the quantum pressures. By comparing with earlier constraints from quantum pressure calculations, we conclude that thermal pressures induced by chameleons are actually of experimental significance.
{"title":"Quantum and thermal pressures from light scalar fields","authors":"Hauke Fischer, Christian Käding, Mario Pitschmann","doi":"10.1016/j.dark.2024.101756","DOIUrl":"10.1016/j.dark.2024.101756","url":null,"abstract":"<div><div>Light scalar fields play a variety of roles in modern physics, especially in cosmology and modified theories of gravity. For this reason, there is a zoo of experiments actively trying to find evidence for many scalar field models that have been proposed in theoretical considerations. Among those are setups in which the pressures expected to be induced by light scalar fields between two parallel plates are studied, for example, Casimir force experiments. While it is known that classical and quantum pressures caused by light scalar fields could have significant impacts on such experiments, in this article, we show that this can also be the case for thermal pressure. More specifically, we derive expressions for the quantum and thermal pressures induced by exchanges of light scalar field fluctuations between two thin parallel plates. As particular examples, we then look at screened scalar fields. For chameleon, symmetron and environment-dependent dilaton models, we find large regions in their parameter spaces that allow for thermal pressures to equal or exceed the quantum pressures. By comparing with earlier constraints from quantum pressure calculations, we conclude that thermal pressures induced by chameleons are actually of experimental significance.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101756"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100014","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 : 2025-02-01DOI: 10.1016/j.dark.2024.101791
Simony Santos da Costa
In this work, I investigate the impact of Dark Energy Spectroscopic Instrument (DESI) Baryonic Acoustic Oscillations (BAO) data on cosmological parameters, focusing on the inflationary spectral index , the amplitude of scalar perturbations , and the matter density parameter . By examining different models of late-time new physics, the inflationary parameters were revealed to be stable when compared with the baseline dataset that used the earlier BAO data from the SDSS collaboration. When combined with Cosmic Microwave Background (CMB) and type Ia supernovae (SNeIa), DESI BAO data leads to a slight reduction in (less than 2%) and modest changes in and , if compared with the same combination but using SDSS BAO data instead, suggesting a subtle shift in matter clustering. These effects may be attributed to a higher expansion rate from dynamical dark energy, changes in the recombination period, or modifications to the matter–radiation equality time. Further analyses of models with dynamical dark energy and free curvature show a consistent trend of reduced , accompanied by slight increases in both and . The results emphasize the importance of the DESI BAO data in refining cosmological parameter estimates and highlight the stability of inflationary parameters across different late-time cosmological models.
{"title":"Impact of DESI BAO Data on Inflationary Parameters: Stability against late-time new physics","authors":"Simony Santos da Costa","doi":"10.1016/j.dark.2024.101791","DOIUrl":"10.1016/j.dark.2024.101791","url":null,"abstract":"<div><div>In this work, I investigate the impact of Dark Energy Spectroscopic Instrument (DESI) Baryonic Acoustic Oscillations (BAO) data on cosmological parameters, focusing on the inflationary spectral index <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>, the amplitude of scalar perturbations <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>, and the matter density parameter <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span>. By examining different models of late-time new physics, the inflationary parameters were revealed to be stable when compared with the baseline dataset that used the earlier BAO data from the SDSS collaboration. When combined with Cosmic Microwave Background (CMB) and type Ia supernovae (SNeIa), DESI BAO data leads to a slight reduction in <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span> (less than 2%) and modest changes in <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>, if compared with the same combination but using SDSS BAO data instead, suggesting a subtle shift in matter clustering. These effects may be attributed to a higher expansion rate from dynamical dark energy, changes in the recombination period, or modifications to the matter–radiation equality time. Further analyses of models with dynamical dark energy and free curvature show a consistent trend of reduced <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>m</mi></mrow></msub></math></span>, accompanied by slight increases in both <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>. The results emphasize the importance of the DESI BAO data in refining cosmological parameter estimates and highlight the stability of inflationary parameters across different late-time cosmological models.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101791"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100215","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 : 2025-02-01DOI: 10.1016/j.dark.2025.101810
Shun-Jia Huang , En-Kun Li , Jian-dong Zhang , Xian Chen , Zucheng Gao , Xin-yi Lin , Yi-Ming Hu
The cosmic distance duality relation (CDDR), expressed as , plays an important role in modern cosmology. In this paper, we propose a new method of testing CDDR using strongly lensed gravitational wave (SLGW) signals. Under the geometric optics approximation, we calculate the gravitational lens effects of two lens models, the point mass and singular isothermal sphere. We use functions of and to parameterize the deviation of CDDR. By reparameterizing the SLGW waveform with CDDR and the distance-redshift relation, we include the deviation parameters of CDDR as waveform parameters. We evaluate the ability of this method by calculating the parameter estimation of simulated SLGW signals from massive binary black holes. We apply the Fisher information matrix and Markov Chain Monte Carlo methods to calculate parameter estimation. We find that with only one SLGW signal, the measurement precision of can reach a considerable level of 0.5-1.3% for and 1.1-2.6% for , depending on the lens model and parameters.
{"title":"An opacity-free method of testing the cosmic distance duality relation using strongly lensed gravitational wave signals","authors":"Shun-Jia Huang , En-Kun Li , Jian-dong Zhang , Xian Chen , Zucheng Gao , Xin-yi Lin , Yi-Ming Hu","doi":"10.1016/j.dark.2025.101810","DOIUrl":"10.1016/j.dark.2025.101810","url":null,"abstract":"<div><div>The cosmic distance duality relation (CDDR), expressed as <span><math><mrow><msub><mrow><mi>D</mi></mrow><mrow><mi>L</mi></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow><mo>=</mo><msup><mrow><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow></mrow><mrow><mn>2</mn></mrow></msup><msub><mrow><mi>D</mi></mrow><mrow><mi>A</mi></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span>, plays an important role in modern cosmology. In this paper, we propose a new method of testing CDDR using strongly lensed gravitational wave (SLGW) signals. Under the geometric optics approximation, we calculate the gravitational lens effects of two lens models, the point mass and singular isothermal sphere. We use functions of <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow><mo>=</mo><mn>1</mn><mo>+</mo><msub><mrow><mi>η</mi></mrow><mrow><mn>0</mn></mrow></msub><mi>z</mi></mrow></math></span> and <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow><mo>=</mo><mn>1</mn><mo>+</mo><msub><mrow><mi>η</mi></mrow><mrow><mn>0</mn></mrow></msub><mi>z</mi><mo>/</mo><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> to parameterize the deviation of CDDR. By reparameterizing the SLGW waveform with CDDR and the distance-redshift relation, we include the deviation parameters <span><math><msub><mrow><mi>η</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> of CDDR as waveform parameters. We evaluate the ability of this method by calculating the parameter estimation of simulated SLGW signals from massive binary black holes. We apply the Fisher information matrix and Markov Chain Monte Carlo methods to calculate parameter estimation. We find that with only one SLGW signal, the measurement precision of <span><math><msub><mrow><mi>η</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> can reach a considerable level of 0.5-1.3% for <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> and 1.1-2.6% for <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span>, depending on the lens model and parameters.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101810"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100224","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 this present work, we introduce a completely new wormhole shape function satisfying the Karmarkar condition that constructs static, spherically symmetric wormhole solutions in the framework of modified gravity. The proposed shape function generating wormholes are asymptotically flat by satisfying the essential conditions. Here, we consider two well-known gravity models, namely the exponential gravity model, and the Tsujikawa gravity model, interestingly, the reported shape function generating wormholes are static, and spherically symmetric structures in the circumstances of the non-existence theorem and supported by the non-exotic matter in those gravity models corresponding to the suitable values of free parameters. Moreover, the non-exotic matter supporting wormholes are in the equilibrium state by satisfying the ToV-equation in both the considered gravity models. We also study the weak gravitational lensing in the spacetime of the present wormhole structures and estimate the deflection angle of light that decreases for increasing values of the impact parameter.
{"title":"Traversable wormholes satisfying the Karmarkar condition in f(R) gravity with deflection angle of light","authors":"Nayan Sarkar , Susmita Sarkar , Moumita Sarkar , Farook Rahaman","doi":"10.1016/j.dark.2025.101828","DOIUrl":"10.1016/j.dark.2025.101828","url":null,"abstract":"<div><div>In this present work, we introduce a completely new wormhole shape function satisfying the Karmarkar condition that constructs static, spherically symmetric wormhole solutions in the framework of modified <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity. The proposed shape function generating wormholes are asymptotically flat by satisfying the essential conditions. Here, we consider two well-known <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity models, namely the exponential <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity model, and the Tsujikawa <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity model, interestingly, the reported shape function generating wormholes are static, and spherically symmetric structures in the circumstances of the non-existence theorem and supported by the non-exotic matter in those <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity models corresponding to the suitable values of free parameters. Moreover, the non-exotic matter supporting wormholes are in the equilibrium state by satisfying the ToV-equation in both the considered <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity models. We also study the weak gravitational lensing in the spacetime of the present wormhole structures and estimate the deflection angle of light that decreases for increasing values of the impact parameter.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101828"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100227","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 : 2025-02-01DOI: 10.1016/j.dark.2025.101813
Mario Ballardini , Alessandro Davoli, Salvatore Samuele Sirletti
<div><div>We investigate the primordial power spectra (PPS) of scalar and tensor perturbations, derived through the slow-roll approximation. By solving the Mukhanov-Sasaki equation and the tensor perturbation equation with Green’s function techniques, we extend the PPS calculations to third-order corrections, providing a comprehensive expansion in terms of slow-roll parameters with an independent approach to the solution of the integrals compared to the one previously presented in the literature. We investigate the accuracy of the analytic predictions starting from first-order corrections up to third-order ones with the numerical solutions of the perturbation equations for a selection of single-field slow-roll inflationary models. We derive the constraints on the Hubble flow functions <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> from <em>Planck</em>, ACT, SPT, and BICEP/Keck data. We find an upper bound <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>≲</mo><mn>0</mn><mo>.</mo><mn>002</mn></mrow></math></span> at 95% CL dominated by BICEP/Keck data and robust to all the different combination of datasets. We derive the constraint <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>≃</mo><mn>0</mn><mo>.</mo><mn>031</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>004</mn></mrow></math></span> at 68% confidence level (CL) from the combination of <em>Planck</em> data and late-time probes such as baryon acoustic oscillations, redshift space distortions, and supernovae data at first order in the slow-roll expansion. The uncertainty on <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> gets larger including second- and third-order corrections, allowing for a non-vanishing running and running of the running respectively, leading to <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>≃</mo><mn>0</mn><mo>.</mo><mn>034</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>007</mn></mrow></math></span> at 68% CL. We find <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>≃</mo><mn>0</mn><mo>.</mo><mn>1</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>4</mn></mrow></math></span> at 95% CL both at second and at third order in the slow-roll expansion of the spectra. <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> remains always unconstrained. The combination of <em>Planck</em> and SPT data, compatible among each others, leads to slightly tighter constraints on <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span>. On the contrary, the combination of <em>Planck</em> data with ACT measurements, which point to higher values of the scalar spectral index compared to <em>Planck</em> findings, leads to shifts in the means and maximum likelihood values for
{"title":"Third-order corrections to the slow-roll expansion: Calculation and constraints with Planck, ACT, SPT, and BICEP/Keck","authors":"Mario Ballardini , Alessandro Davoli, Salvatore Samuele Sirletti","doi":"10.1016/j.dark.2025.101813","DOIUrl":"10.1016/j.dark.2025.101813","url":null,"abstract":"<div><div>We investigate the primordial power spectra (PPS) of scalar and tensor perturbations, derived through the slow-roll approximation. By solving the Mukhanov-Sasaki equation and the tensor perturbation equation with Green’s function techniques, we extend the PPS calculations to third-order corrections, providing a comprehensive expansion in terms of slow-roll parameters with an independent approach to the solution of the integrals compared to the one previously presented in the literature. We investigate the accuracy of the analytic predictions starting from first-order corrections up to third-order ones with the numerical solutions of the perturbation equations for a selection of single-field slow-roll inflationary models. We derive the constraints on the Hubble flow functions <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> from <em>Planck</em>, ACT, SPT, and BICEP/Keck data. We find an upper bound <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>≲</mo><mn>0</mn><mo>.</mo><mn>002</mn></mrow></math></span> at 95% CL dominated by BICEP/Keck data and robust to all the different combination of datasets. We derive the constraint <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>≃</mo><mn>0</mn><mo>.</mo><mn>031</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>004</mn></mrow></math></span> at 68% confidence level (CL) from the combination of <em>Planck</em> data and late-time probes such as baryon acoustic oscillations, redshift space distortions, and supernovae data at first order in the slow-roll expansion. The uncertainty on <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> gets larger including second- and third-order corrections, allowing for a non-vanishing running and running of the running respectively, leading to <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>≃</mo><mn>0</mn><mo>.</mo><mn>034</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>007</mn></mrow></math></span> at 68% CL. We find <span><math><mrow><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>≃</mo><mn>0</mn><mo>.</mo><mn>1</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>4</mn></mrow></math></span> at 95% CL both at second and at third order in the slow-roll expansion of the spectra. <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> remains always unconstrained. The combination of <em>Planck</em> and SPT data, compatible among each others, leads to slightly tighter constraints on <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span>. On the contrary, the combination of <em>Planck</em> data with ACT measurements, which point to higher values of the scalar spectral index compared to <em>Planck</em> findings, leads to shifts in the means and maximum likelihood values for ","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101813"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100230","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 : 2025-02-01DOI: 10.1016/j.dark.2025.101821
D.D. Pawar , P.S. Gaikwad , Shah Muhammad , Euaggelos E. Zotos
In this study, we explore cosmological models within the framework of gravity by utilizing the energy–momentum tensor for a perfect fluid to solve the corresponding field equations. We derive key cosmological parameters, including the Hubble parameter . Parameter constraints were applied using the test, resulting in best-fit values of and , with a strong alignment with the CDM model (; RMSE = 11.4068). The deceleration parameter, calculated in terms of cosmic time and redshift, indicates a transition from deceleration to acceleration, consistent with current observations of an accelerating universe. Additionally, we examined the pressure , energy density , and equation of state parameter for two specific models: Model-I for and Model-II for . The Om diagnostic plotted against redshift for shows that stabilizes around 0.3 after a slight deviation at , with a narrow uncertainty band. The model closely aligns with CDM at higher redshifts. The pair of statefinder diagnostics vs. is also discussed, and our model for represents the CDM model.
{"title":"Perfect fluid dynamics with observational constraint in the framework of f(T) gravity","authors":"D.D. Pawar , P.S. Gaikwad , Shah Muhammad , Euaggelos E. Zotos","doi":"10.1016/j.dark.2025.101821","DOIUrl":"10.1016/j.dark.2025.101821","url":null,"abstract":"<div><div>In this study, we explore cosmological models within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity by utilizing the energy–momentum tensor for a perfect fluid to solve the corresponding field equations. We derive key cosmological parameters, including the Hubble parameter <span><math><mi>H</mi></math></span>. Parameter constraints were applied using the <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> test, resulting in best-fit values of <span><math><mrow><mi>β</mi><mo>=</mo><mn>108</mn><mo>.</mo><mn>5</mn><msubsup><mrow><mn>1</mn></mrow><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>40</mn></mrow><mrow><mo>+</mo><mn>0</mn><mo>.</mo><mn>41</mn></mrow></msubsup></mrow></math></span> and <span><math><mrow><msub><mrow><mi>ξ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mo>−</mo><msubsup><mrow><mn>0</mn><mo>.</mo><mn>14717</mn></mrow><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>00096</mn></mrow><mrow><mo>+</mo><mn>0</mn><mo>.</mo><mn>00094</mn></mrow></msubsup></mrow></math></span>, with a strong alignment with the <span><math><mi>Λ</mi></math></span>CDM model (<span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>9280</mn></mrow></math></span>; RMSE = 11.4068). The deceleration parameter, calculated in terms of cosmic time and redshift, indicates a transition from deceleration to acceleration, consistent with current observations of an accelerating universe. Additionally, we examined the pressure <span><math><mi>p</mi></math></span>, energy density <span><math><mi>ρ</mi></math></span>, and equation of state parameter <span><math><mi>ω</mi></math></span> for two specific models: Model-I for <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>λ</mi><mi>T</mi></mrow></math></span> and Model-II for <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>T</mi><mo>+</mo><mi>β</mi><msup><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>. The Om diagnostic plotted against redshift for <span><math><msub><mrow><mi>ξ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> shows that <span><math><mrow><mi>Ω</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> stabilizes around 0.3 after a slight deviation at <span><math><mrow><mi>z</mi><mo>≈</mo><mn>0</mn></mrow></math></span>, with a narrow uncertainty band. The model closely aligns with <span><math><mi>Λ</mi></math></span>CDM at higher redshifts. The pair of statefinder diagnostics <span><math><mi>r</mi></math></span> vs. <span><math><mi>s</mi></math></span> is also discussed, and our model for <span><math><mrow><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>s</mi><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo>)</mo></mrow></mrow></math></span> represents the <span><math><mi>Λ</mi></math></span>CDM model.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101821"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100689","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 : 2025-02-01DOI: 10.1016/j.dark.2024.101770
Bo Yang , Yi Xie , Wenbin Lin
Following the works of Rahaman et al. (2018) and Chen et al. (2024) in which the dyon black holes and covariant loop quantum black holes were respectively taken as effective descriptions of the exterior field of the Sun and tested by the motion of planets of the Solar System, we hypothesize that the exterior solution of a regular black hole with an asymptotically Minkowski core might be adopted to describe the external field of a spherical celestial body featuring a suppression parameter and constrain such a parameter. We calculate the first-order post-Newtonian relativistic periastron advance of a timelike particle in this spacetime. We then test this model in the five binary pulsars and Solar System, determining its upper limits as . Compared with the result of obtained from the shadow of Sgr A*, our result is improved by 10 orders of magnitude.
{"title":"Probing the regular spacetime with an asymptotically Minkowski core by precessing motion","authors":"Bo Yang , Yi Xie , Wenbin Lin","doi":"10.1016/j.dark.2024.101770","DOIUrl":"10.1016/j.dark.2024.101770","url":null,"abstract":"<div><div>Following the works of Rahaman et al. (2018) and Chen et al. (2024) in which the dyon black holes and covariant loop quantum black holes were respectively taken as effective descriptions of the exterior field of the Sun and tested by the motion of planets of the Solar System, we hypothesize that the exterior solution of a regular black hole with an asymptotically Minkowski core might be adopted to describe the external field of a spherical celestial body featuring a suppression parameter <span><math><mi>ℓ</mi></math></span> and constrain such a parameter. We calculate the first-order post-Newtonian relativistic periastron advance of a timelike particle in this spacetime. We then test this model in the five binary pulsars and Solar System, determining its upper limits as <span><math><mrow><mi>ℓ</mi><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mspace></mspace><mi>m</mi></mrow></math></span>. Compared with the result of <span><math><mrow><mi>ℓ</mi><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>8</mn></mrow></msup><mspace></mspace><mi>m</mi></mrow></math></span> obtained from the shadow of Sgr A*, our result is improved by 10 orders of magnitude.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101770"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095536","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 : 2025-02-01DOI: 10.1016/j.dark.2024.101774
Gabriel Brandão de Gracia , Roldão da Rocha , Rodolfo José Bueno Rogerio , Cheng-Yang Lee
In this paper, we provide a set of Hermitian interactions for quantum fields based on Elko, considering the recent achievements concerning the most general form of singular spinors and Wigner degeneracy. We consider Hermiticity and renormalizability a criterion to define the derivative Elko–Higgs interaction as the suitable candidate for a dark coupling. Then, the free parameters of the model are fixed by cosmological constraints on the dark matter abundance and limits on the electron-dark matter scattering mediated by the Higgs.
{"title":"On Wigner degeneracy in Elko theory: Hermiticity and dark matter","authors":"Gabriel Brandão de Gracia , Roldão da Rocha , Rodolfo José Bueno Rogerio , Cheng-Yang Lee","doi":"10.1016/j.dark.2024.101774","DOIUrl":"10.1016/j.dark.2024.101774","url":null,"abstract":"<div><div>In this paper, we provide a set of Hermitian interactions for quantum fields based on Elko, considering the recent achievements concerning the most general form of singular spinors and Wigner degeneracy. We consider Hermiticity and renormalizability a criterion to define the derivative Elko–Higgs interaction as the suitable candidate for a dark coupling. Then, the free parameters of the model are fixed by cosmological constraints on the dark matter abundance and limits on the electron-dark matter scattering mediated by the Higgs.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101774"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099711","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 this study, we examine the effects of weak gravitational lensing and determine the shadow radius around black holes within the regular scale-dependent spacetime, also accounting for both uniform and nonuniform plasma models. By analyzing various gravitational lens, we compare corrections to vacuum lensing due to gravitational effects within plasma and plasma inhomogeneity, finding that these effects could be observed in hot gas within galaxy clusters. Starting with the orbits of photons around a regular scale-dependent black hole, we investigate the shadow and weak gravitational lensing phenomena. Utilizing observational data from the Event Horizon Telescope (EHT) for SgrA*, we constrain on parameter within regular scale-dependent gravity. To connect our findings to observations, we examine the magnification and positioning of lensed images, along with the weak deflection angle and magnification for sources near different galaxies.
{"title":"Testing regular scale-dependent black hole space time using particle dynamics: Shadow and gravitational weak lensing","authors":"Tolibjon Ibrokhimov , Ziyodulla Turakhonov , Farruh Atamurotov , Ahmadjon Abdujabbarov , Koblandy Yerzhanov , Gulnur Bauyrzhan , Alisher Abduvokhidov","doi":"10.1016/j.dark.2024.101778","DOIUrl":"10.1016/j.dark.2024.101778","url":null,"abstract":"<div><div>In this study, we examine the effects of weak gravitational lensing and determine the shadow radius around black holes within the regular scale-dependent spacetime, also accounting for both uniform and nonuniform plasma models. By analyzing various gravitational lens, we compare corrections to vacuum lensing due to gravitational effects within plasma and plasma inhomogeneity, finding that these effects could be observed in hot gas within galaxy clusters. Starting with the orbits of photons around a regular scale-dependent black hole, we investigate the shadow and weak gravitational lensing phenomena. Utilizing observational data from the Event Horizon Telescope (EHT) for SgrA*, we constrain on parameter within regular scale-dependent gravity. To connect our findings to observations, we examine the magnification and positioning of lensed images, along with the weak deflection angle and magnification for sources near different galaxies.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"47 ","pages":"Article 101778"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100214","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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