Pub Date : 2026-03-01Epub Date: 2026-01-09DOI: 10.1016/j.jheap.2026.100553
N. Sadeghnezhad , R. Jalalzadeh , Z. Davari , B. Afshar
The cosmological implications of New Tsallis holographic dark energy (NTHDE) in Rastall theory have been studied. Using the data set that includes DESI BAO (DR2), PantheonPlus SNe Ia, H(z) measurements, and BBN and the MCMC analysis, the key cosmological and model-specific parameters are constrained. The result is compared with that of the ΛCDM model indicating that in addition to providing a viable dynamical dark energy framework, predictions for H(z) are slightly more consistent with intermediate-redshift observations. Generally, the model remains compatible with current data and offers testable deviations from ΛCDM for upcoming surveys. It is also seen that when the energy density of quantum fields in vacuum, exposed by NTHDE, is combined with the Rastall correction term to the general relativity, a plausible candidate for dynamical dark energy is obtained that mimic the current value of the dark energy density parameter reported in the ΛCDM model. The latter cannot be repeated by NTHDE alone. Although NTHDE is not always classically stable, dynamical stability analysis reveals a stable de-Sitter fate for the Cosmos. The study also confirms previous theoretical and observational constraints on the Rastall parameter obtained by focusing on the thermodynamics, early universe, pulsars, and the early-type galaxies.
研究了新萨利斯全息暗能量(NTHDE)在拉斯托尔理论中的宇宙学意义。利用包括DESI BAO (DR2)、PantheonPlus snia、H(z)测量和BBN以及MCMC分析在内的数据集,对关键的宇宙学和模型特定参数进行了约束。结果与ΛCDM模型的结果进行了比较,表明除了提供一个可行的动态暗能量框架外,对H(z)的预测与中间红移观测结果略微一致。一般来说,该模型与当前数据保持兼容,并为即将进行的调查提供ΛCDM的可测试偏差。当NTHDE暴露的真空中量子场的能量密度与广义相对论的Rastall修正项相结合时,可以得到一个模拟ΛCDM模型中报告的暗能量密度参数当前值的动态暗能量候选者。后者不能仅由NTHDE来重复。虽然NTHDE并不总是经典稳定的,但动态稳定性分析揭示了宇宙的稳定de-Sitter命运。该研究还证实了先前通过热力学、早期宇宙、脉冲星和早期型星系获得的拉斯托参数的理论和观测约束。
{"title":"Observational constraints on New Tsallis holographic energy in Rastall theory","authors":"N. Sadeghnezhad , R. Jalalzadeh , Z. Davari , B. Afshar","doi":"10.1016/j.jheap.2026.100553","DOIUrl":"10.1016/j.jheap.2026.100553","url":null,"abstract":"<div><div>The cosmological implications of New Tsallis holographic dark energy (NTHDE) in Rastall theory have been studied. Using the data set that includes DESI BAO (DR2), PantheonPlus SNe Ia, <em>H</em>(<em>z</em>) measurements, and BBN and the MCMC analysis, the key cosmological and model-specific parameters are constrained. The result is compared with that of the ΛCDM model indicating that in addition to providing a viable dynamical dark energy framework, predictions for <em>H</em>(<em>z</em>) are slightly more consistent with intermediate-redshift observations. Generally, the model remains compatible with current data and offers testable deviations from ΛCDM for upcoming surveys. It is also seen that when the energy density of quantum fields in vacuum, exposed by NTHDE, is combined with the Rastall correction term to the general relativity, a plausible candidate for dynamical dark energy is obtained that mimic the current value of the dark energy density parameter reported in the ΛCDM model. The latter cannot be repeated by NTHDE alone. Although NTHDE is not always classically stable, dynamical stability analysis reveals a stable de-Sitter fate for the Cosmos. The study also confirms previous theoretical and observational constraints on the Rastall parameter obtained by focusing on the thermodynamics, early universe, pulsars, and the early-type galaxies.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100553"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-03-01Epub Date: 2025-12-23DOI: 10.1016/j.jheap.2025.100537
Guoying Zhao , Weikang Zheng , Rong-Feng Shen , Qingcang Shui , Dongyue Li , Chang Zhou , Tianci Zheng , Weimin Yuan , HeYang Liu , Junfeng Wang , Alexei V. Filippenko , Thomas G. Brink , Chong Ge , Jordan Forman , Mayra Gutierrez , Isabelle Jones , Ravjit Kaur , Naunet Leonhardes-Barboza , Petra Mengistu , Avi Patel , Michele N. Woodland
Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1–0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221–0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the Hα emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of ∼ 7.1 ks. The peak luminosity in the 0.5–4.0 keV energy band reached ∼ 1.3 × 1031 erg s, with a total energy release of ∼ 9.1 × 1034 erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and Hα-X-ray energy correlation. This discovery underscores EP’s capability in understanding stellar magnetic activity via observing stellar transients.
{"title":"Einstein Probe discovery of an X-ray flare from K-type star PM J23221-0301","authors":"Guoying Zhao , Weikang Zheng , Rong-Feng Shen , Qingcang Shui , Dongyue Li , Chang Zhou , Tianci Zheng , Weimin Yuan , HeYang Liu , Junfeng Wang , Alexei V. Filippenko , Thomas G. Brink , Chong Ge , Jordan Forman , Mayra Gutierrez , Isabelle Jones , Ravjit Kaur , Naunet Leonhardes-Barboza , Petra Mengistu , Avi Patel , Michele N. Woodland","doi":"10.1016/j.jheap.2025.100537","DOIUrl":"10.1016/j.jheap.2025.100537","url":null,"abstract":"<div><div>Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1–0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221–0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the H<em>α</em> emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of ∼ 7.1 ks. The peak luminosity in the 0.5–4.0 keV energy band reached ∼ 1.3 × 10<sup>31</sup> erg s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>, with a total energy release of ∼ 9.1 × 10<sup>34</sup> erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and H<em>α</em>-X-ray energy correlation. This discovery underscores EP’s capability in understanding stellar magnetic activity via observing stellar transients.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100537"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 particle dynamics and observational signatures in the spacetime of a charged black hole arising from effective quantum gravity. Starting from the geodesic motion of neutral particles, we derive the equations of motion and analyze the impact of quantum corrections on the effective potential, the stability of circular orbits, and the innermost stable circular orbit (ISCO). The results show that quantum effects can significantly shift the ISCO radius and alter orbital stability compared to the Schwarzschild case. The analysis is further extended to the motion of charged particles in the presence of an external magnetic field, revealing strong dependencies on the sign and magnitude of the particle’s charge. The Lorentz force is found to modify the ISCO location and allow for trapping or escape trajectories, highlighting the importance of electromagnetic interactions in realistic astrophysical environments. Finally, by performing a MCMC fitting to the orbital motion of the S2 star around Sgr A*, we constrain the black hole parameters and find them consistent with current observational bounds. Our results suggest that quantum corrected charged black holes can imprint measurable effects on particle dynamics, offering potential tests of alternative gravity models through high-precision astrophysical observations.
我们研究了由有效量子引力引起的带电黑洞的粒子动力学和观测特征。从中性粒子的测地线运动出发,推导了运动方程,分析了量子修正对有效势、圆轨道稳定性和最内层稳定圆轨道(ISCO)的影响。结果表明,与史瓦西情况相比,量子效应可以显著改变ISCO半径并改变轨道稳定性。分析进一步扩展到带电粒子在外部磁场存在下的运动,揭示了对粒子电荷的符号和大小的强烈依赖。发现洛伦兹力可以改变ISCO的位置,并允许捕获或逃逸轨迹,突出了电磁相互作用在现实天体物理环境中的重要性。最后,通过对Sgr a *周围S2恒星的轨道运动进行MCMC拟合,我们约束了黑洞参数,并发现它们与当前的观测范围一致。我们的研究结果表明,量子修正带电黑洞可以对粒子动力学产生可测量的影响,通过高精度天体物理观测为替代引力模型提供了潜在的测试。
{"title":"Testing quantum-corrected black hole through particle dynamics and S2 star observations","authors":"Bakhodirkhon Saidov , Bakhtiyor Narzilloev , Ahmadjon Abdujabbarov , Ibrar Hussain , Bobomurat Ahmedov , Chengxun Yuan , Chen Zhou","doi":"10.1016/j.jheap.2025.100543","DOIUrl":"10.1016/j.jheap.2025.100543","url":null,"abstract":"<div><div>We investigate particle dynamics and observational signatures in the spacetime of a charged black hole arising from effective quantum gravity. Starting from the geodesic motion of neutral particles, we derive the equations of motion and analyze the impact of quantum corrections on the effective potential, the stability of circular orbits, and the innermost stable circular orbit (ISCO). The results show that quantum effects can significantly shift the ISCO radius and alter orbital stability compared to the Schwarzschild case. The analysis is further extended to the motion of charged particles in the presence of an external magnetic field, revealing strong dependencies on the sign and magnitude of the particle’s charge. The Lorentz force is found to modify the ISCO location and allow for trapping or escape trajectories, highlighting the importance of electromagnetic interactions in realistic astrophysical environments. Finally, by performing a MCMC fitting to the orbital motion of the S2 star around Sgr A*, we constrain the black hole parameters and find them consistent with current observational bounds. Our results suggest that quantum corrected charged black holes can imprint measurable effects on particle dynamics, offering potential tests of alternative gravity models through high-precision astrophysical observations.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100543"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-03-01Epub Date: 2025-12-17DOI: 10.1016/j.jheap.2025.100533
Andronikos Paliathanasis , Genly Leon , Yoelsy Leyva , Giuseppe Gaetano Luciano , Amare Abebe
We study quantum corrections to the ΛCDM model arising from a minimum measurable length in Heisenberg’s uncertainty principle. We focus on a higher-order Generalized Uncertainty Principle, beyond the quadratic form. This generalized GUP introduces two free parameters, and we determine the modified Friedmann equation. This framework leads to a perturbative cosmological model that naturally reduces to ΛCDM in an appropriate limiting case of the deformation parameters. We construct the modified cosmological scenario, analyze its deviations from the standard case, and examine it as a mechanism for the description of dynamical dark energy. To constrain the model, we employ Cosmic Chronometers, the latest Baryon Acoustic Oscillations from the DESI DR2 release, and Supernova data from the PantheonPlus and Union3 catalogues. Our analysis indicates that the modified GUP model is statistically competitive with the ΛCDM scenario, providing comparable or even improved fits to some of the combined datasets. Moreover, the data constrain the deformation parameter of the GUP model, with the preferred value found to be negative, which corresponds to a phantom regime in the effective dynamical dark energy description.
{"title":"Challenging ΛCDM with higher-order GUP corrections","authors":"Andronikos Paliathanasis , Genly Leon , Yoelsy Leyva , Giuseppe Gaetano Luciano , Amare Abebe","doi":"10.1016/j.jheap.2025.100533","DOIUrl":"10.1016/j.jheap.2025.100533","url":null,"abstract":"<div><div>We study quantum corrections to the ΛCDM model arising from a minimum measurable length in Heisenberg’s uncertainty principle. We focus on a higher-order Generalized Uncertainty Principle, beyond the quadratic form. This generalized GUP introduces two free parameters, and we determine the modified Friedmann equation. This framework leads to a perturbative cosmological model that naturally reduces to ΛCDM in an appropriate limiting case of the deformation parameters. We construct the modified cosmological scenario, analyze its deviations from the standard case, and examine it as a mechanism for the description of dynamical dark energy. To constrain the model, we employ Cosmic Chronometers, the latest Baryon Acoustic Oscillations from the DESI DR2 release, and Supernova data from the PantheonPlus and Union3 catalogues. Our analysis indicates that the modified GUP model is statistically competitive with the ΛCDM scenario, providing comparable or even improved fits to some of the combined datasets. Moreover, the data constrain the deformation parameter of the GUP model, with the preferred value found to be negative, which corresponds to a phantom regime in the effective dynamical dark energy description.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100533"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-03-01Epub Date: 2025-11-24DOI: 10.1016/j.jheap.2025.100517
Manuel Gonzalez-Espinoza , Genly Leon , Yoelsy Leyva , Giovanni Otalora , Andronikos Paliathanasis , Aleksander Kozak
We study scalar field cosmologies in higher-order gravity, inspired by the Pais–Uhlenbeck oscillator, which admits a fourth-order ghost-free sector. By recasting the equations as a slow–fast system, we analyze phase-space evolution under exponential, power-law, and arbitrary potentials using both analytical and geometric methods. The full system exhibits a rational structure with singular surfaces and, under a slow manifold constraint, reduces to a regular four-dimensional form that supports global analysis and perturbative stability. The -deviser technique reconstructs potential-adapted functions , enabling attractor classification and center manifold analysis. Two-field extensions yield scaling laws and tracking behavior in the quintom regime. In the quintessence regime, we examine de Sitter stability, incorporating radiation and dust to model realistic transitions, and derive analytic expressions for and across reconstructed inflationary potentials-obtained from standard, Gaussian, hybrid, extended, and logarithmic expansions of the scale factor-with a scalar field evolving linearly in time. Our results confirm the viability of Pais–Uhlenbeck scalar models for inflation and dark energy, offering tools to study attractors and bifurcations in higher-derivative cosmology.
{"title":"Slow–fast evolution of scalar fields in higher-order cosmological gravity dynamics inspired by the Pais–Uhlenbeck oscillator","authors":"Manuel Gonzalez-Espinoza , Genly Leon , Yoelsy Leyva , Giovanni Otalora , Andronikos Paliathanasis , Aleksander Kozak","doi":"10.1016/j.jheap.2025.100517","DOIUrl":"10.1016/j.jheap.2025.100517","url":null,"abstract":"<div><div>We study scalar field cosmologies in higher-order gravity, inspired by the Pais–Uhlenbeck oscillator, which admits a fourth-order ghost-free sector. By recasting the equations as a slow–fast system, we analyze phase-space evolution under exponential, power-law, and arbitrary potentials using both analytical and geometric methods. The full system exhibits a rational structure with singular surfaces and, under a slow manifold constraint, reduces to a regular four-dimensional form that supports global analysis and perturbative stability. The <span><math><mi>f</mi></math></span>-deviser technique reconstructs potential-adapted functions <span><math><mrow><mi>f</mi><mo>(</mo><mi>λ</mi><mo>)</mo></mrow></math></span>, enabling attractor classification and center manifold analysis. Two-field extensions yield scaling laws and tracking behavior in the quintom regime. In the quintessence regime, we examine de Sitter stability, incorporating radiation and dust to model realistic transitions, and derive analytic expressions for <span><math><msub><mi>n</mi><mi>s</mi></msub></math></span> and <span><math><mi>r</mi></math></span> across reconstructed inflationary potentials-obtained from standard, Gaussian, hybrid, extended, and logarithmic expansions of the scale factor-with a scalar field evolving linearly in time. Our results confirm the viability of Pais–Uhlenbeck scalar models for inflation and dark energy, offering tools to study attractors and bifurcations in higher-derivative cosmology.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"51 ","pages":"Article 100517"},"PeriodicalIF":10.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-02-01Epub Date: 2025-09-29DOI: 10.1016/j.jheap.2025.100487
Giuseppe Gaetano Luciano
In the framework of entropic cosmology, entropic forces arising at the cosmological horizon have been proposed as an alternative mechanism to explain the Universe's current accelerated phase. However, recent studies have shown that, under the Clausius relation and assuming a linear mass-to-horizon (MHR) relation, all entropic force models reduce to the original Bekenstein-Hawking formulation, regardless of the specific form of the horizon entropy. As a result, they inherit the same observational limitations in accounting for cosmic dynamics. To address this issue, a generalized MHR has been introduced, providing the foundation for a modified cosmological scenario rooted in the gravity-thermodynamics conjecture. In this work, we explore the implications of this generalized framework for early-Universe dynamics. Specifically, we analyze the growth of matter perturbations within the spherical Top-Hat formalism in the linear regime, showing that the density contrast profile is significantly influenced by the modified background dynamics predicted by the model. Moreover, considering the sensitivity of upcoming gravitational wave detectors in the sub- range, we examine the impact on the relic abundance of Primordial Gravitational Waves (PGWs), identifying parameter regions where deviations from standard cosmology may arise through an enhanced PGW spectrum.
{"title":"Modified cosmology through generalized mass-to-horizon entropy: Implications for structure growth and primordial gravitational waves","authors":"Giuseppe Gaetano Luciano","doi":"10.1016/j.jheap.2025.100487","DOIUrl":"10.1016/j.jheap.2025.100487","url":null,"abstract":"<div><div>In the framework of entropic cosmology, entropic forces arising at the cosmological horizon have been proposed as an alternative mechanism to explain the Universe's current accelerated phase. However, recent studies have shown that, under the Clausius relation and assuming a linear mass-to-horizon (MHR) relation, all entropic force models reduce to the original Bekenstein-Hawking formulation, regardless of the specific form of the horizon entropy. As a result, they inherit the same observational limitations in accounting for cosmic dynamics. To address this issue, a generalized MHR has been introduced, providing the foundation for a modified cosmological scenario rooted in the gravity-thermodynamics conjecture. In this work, we explore the implications of this generalized framework for early-Universe dynamics. Specifically, we analyze the growth of matter perturbations within the spherical Top-Hat formalism in the linear regime, showing that the density contrast profile is significantly influenced by the modified background dynamics predicted by the model. Moreover, considering the sensitivity of upcoming gravitational wave detectors in the sub-<span><math><msup><mrow><mn>10</mn></mrow><mrow><mn>3</mn></mrow></msup><mspace></mspace><mrow><mi>Hz</mi></mrow></math></span> range, we examine the impact on the relic abundance of Primordial Gravitational Waves (PGWs), identifying parameter regions where deviations from standard cosmology may arise through an enhanced PGW spectrum.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"50 ","pages":"Article 100487"},"PeriodicalIF":10.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-02-01Epub Date: 2025-09-22DOI: 10.1016/j.jheap.2025.100471
S.D. Odintsov , V.K. Oikonomou , G.S. Sharov
A class of viable gravity models which can provide a unified description of inflation with the dark energy era is confronted with the latest observational data on the dark energy era. These models have the unique characteristic that the de Sitter scalaron mass in the Einstein frame counterpart theory is a monotonic function of the curvature, which renders them viable descriptions for both the inflationary and the late-time acceleration eras. We also compare these models with other well-known viable gravity models and with the Λ-Cold-Dark-Matter model. As we show, the most phenomenologically successful models are those which deviate significantly from the Λ-Cold-Dark-Matter model. Also some of the models presented, provide a statistically favorable description of the dark energy eras, compared with the exponential gravity model and of course compared with the Λ-Cold-Dark-Matter model. All the models we present in this article are confronted with the observational data from the Planck collaboration, the Pantheon plus data from Type Ia supernovae, the two rounds of observations of the Dark Energy Spectroscopic Instrument, data from baryon acoustic oscillations and the Hubble constant measurements. As we show, two of the models are statistically favorable by the data.
{"title":"Dynamical dark energy from F(R) gravity models unifying inflation with dark energy: Confronting the latest observational data","authors":"S.D. Odintsov , V.K. Oikonomou , G.S. Sharov","doi":"10.1016/j.jheap.2025.100471","DOIUrl":"10.1016/j.jheap.2025.100471","url":null,"abstract":"<div><div>A class of viable <span><math><mi>F</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span> gravity models which can provide a unified description of inflation with the dark energy era is confronted with the latest observational data on the dark energy era. These models have the unique characteristic that the de Sitter scalaron mass in the Einstein frame counterpart theory is a monotonic function of the curvature, which renders them viable descriptions for both the inflationary and the late-time acceleration eras. We also compare these models with other well-known viable <span><math><mi>F</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span> gravity models and with the Λ-Cold-Dark-Matter model. As we show, the most phenomenologically successful models are those which deviate significantly from the Λ-Cold-Dark-Matter model. Also some of the models presented, provide a statistically favorable description of the dark energy eras, compared with the exponential <span><math><mi>F</mi><mo>(</mo><mi>R</mi><mo>)</mo></math></span> gravity model and of course compared with the Λ-Cold-Dark-Matter model. All the models we present in this article are confronted with the observational data from the Planck collaboration, the Pantheon plus data from Type Ia supernovae, the two rounds of observations of the Dark Energy Spectroscopic Instrument, data from baryon acoustic oscillations and the Hubble constant measurements. As we show, two of the models are statistically favorable by the data.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"50 ","pages":"Article 100471"},"PeriodicalIF":10.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-02-01Epub Date: 2025-10-15DOI: 10.1016/j.jheap.2025.100495
Amit Samaddar, S. Surendra Singh
We examine a modified teleparallel gravity model defined by by introducing an exponential diagnostic of the form . This novel form captures smooth redshift evolution and allows for a flexible, model-independent probe of dark energy dynamics. We derive a Hubble function from this expression and use MCMC analysis with 31 CC, 26 BAO and 1701 Pantheon+ data points to constrain the model parameters. The best-fit results yield km/s/Mpc, and which is consistent with local values. Statistical model selection using AIC and BIC shows that while our model fits the data comparably to ΛCDM, AIC indicates only moderate disfavor, whereas BIC—due to its stronger penalty for additional parameters—provides strong to very strong evidence in favor of the simpler ΛCDM model. Our model predicts a transition redshift , present , and . It satisfies NEC and DEC, closely tracks ΛCDM in the statefinder plane and estimates a cosmic age of Gyr which confirms its strength in explaining late-time acceleration. Our findings demonstrate that the exponential parameterization provides a robust and insightful approach to trace dark energy evolution within modified gravity frameworks.
{"title":"Cosmological insights from an exponential Om(z) function in f(T,TG) gravity framework","authors":"Amit Samaddar, S. Surendra Singh","doi":"10.1016/j.jheap.2025.100495","DOIUrl":"10.1016/j.jheap.2025.100495","url":null,"abstract":"<div><div>We examine a modified teleparallel gravity model defined by <span><math><mi>f</mi><mo>(</mo><mi>T</mi><mo>,</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>)</mo><mo>=</mo><mi>T</mi><mo>+</mo><mi>γ</mi><msqrt><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>G</mi></mrow></msub></mrow></msqrt><mo>+</mo><mi>δ</mi><msqrt><mrow><mi>T</mi></mrow></msqrt></math></span> by introducing an exponential <span><math><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo></math></span> diagnostic of the form <span><math><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>=</mo><mi>α</mi><msup><mrow><mi>e</mi></mrow><mrow><mfrac><mrow><mi>z</mi></mrow><mrow><mn>1</mn><mo>+</mo><mi>z</mi></mrow></mfrac></mrow></msup><mo>+</mo><mi>β</mi></math></span>. This novel form captures smooth redshift evolution and allows for a flexible, model-independent probe of dark energy dynamics. We derive a Hubble function from this expression and use MCMC analysis with 31 CC, 26 BAO and 1701 Pantheon+ data points to constrain the model parameters. The best-fit results yield <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>∈</mo><mo>[</mo><mn>68.46</mn><mo>,</mo><mn>77.38</mn><mo>]</mo></math></span> km/s/Mpc, <span><math><mi>α</mi><mo>∈</mo><mo>[</mo><mo>−</mo><mn>0.232</mn><mo>,</mo><mo>−</mo><mn>0.068</mn><mo>]</mo></math></span> and <span><math><mi>β</mi><mo>∈</mo><mo>[</mo><mn>0.218</mn><mo>,</mo><mn>0.560</mn><mo>]</mo></math></span> which is consistent with local <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> values. Statistical model selection using AIC and BIC shows that while our model fits the data comparably to ΛCDM, AIC indicates only moderate disfavor, whereas BIC—due to its stronger penalty for additional parameters—provides strong to very strong evidence in favor of the simpler ΛCDM model. Our model predicts a transition redshift <span><math><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi><mi>r</mi></mrow></msub><mo>≈</mo><mo>(</mo><mn>0.48</mn><mo>−</mo><mn>0.54</mn><mo>)</mo></math></span>, present <span><math><msub><mrow><mi>q</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>≈</mo><mo>−</mo><mn>0.34</mn></math></span>, and <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>≈</mo><mo>−</mo><mn>0.33</mn></math></span>. It satisfies NEC and DEC, closely tracks ΛCDM in the statefinder plane and estimates a cosmic age of <span><math><mo>(</mo><mn>13.28</mn><mo>−</mo><mn>13.87</mn><mo>)</mo></math></span> Gyr which confirms its strength in explaining late-time acceleration. Our findings demonstrate that the exponential <span><math><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo></math></span> parameterization provides a robust and insightful approach to trace dark energy evolution within modified gravity frameworks.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"50 ","pages":"Article 100495"},"PeriodicalIF":10.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-02-01Epub Date: 2025-09-25DOI: 10.1016/j.jheap.2025.100486
Meghanil Sinha, S. Surendra Singh
This manuscript studies the Bose-Einstein condensate (BEC) stars in the light of gravity here with Durgapal-Fuloria (DP) metric ansatz. The function under this study features as , where η represents the coupling constant. With the help of it, we have formulated a stellar model describing the isotropic matter here within. Our analysis covers energy conditions, equation of state (EoS) parameter and gradients of the energy-momentum tensor components for a valid BEC stellar framework within gravitational theory with satisfactory results. The model's stability has been validated via multiple stability criteria viz., the velocity of sound, study of adiabatic index and surface redshift where all are found to be lying within the acceptable range for our stellar model. Thus in all the cases we have found our model to be stable and realistic. From the graphical representations the impact of the coupling constant and the parameter of the DP metric potential are clearly visible. Thus we can state that with all the above-mentioned features we have introduced new stellar solutions for BEC stars with enhanced precise results in this modified gravity.
{"title":"Durgapal-Fuloria Bose-Einstein condensate stars within f(R,T) gravity theory","authors":"Meghanil Sinha, S. Surendra Singh","doi":"10.1016/j.jheap.2025.100486","DOIUrl":"10.1016/j.jheap.2025.100486","url":null,"abstract":"<div><div>This manuscript studies the Bose-Einstein condensate (BEC) stars in the light of <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></math></span> gravity here with Durgapal-Fuloria (DP) metric ansatz. The function under this study features as <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo><mo>=</mo><mi>R</mi><mo>+</mo><mn>2</mn><mi>η</mi><mi>T</mi></math></span>, where <em>η</em> represents the coupling constant. With the help of it, we have formulated a stellar model describing the isotropic matter here within. Our analysis covers energy conditions, equation of state (EoS) parameter and gradients of the energy-momentum tensor components for a valid BEC stellar framework within <span><math><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></math></span> gravitational theory with satisfactory results. The model's stability has been validated via multiple stability criteria viz., the velocity of sound, study of adiabatic index and surface redshift where all are found to be lying within the acceptable range for our stellar model. Thus in all the cases we have found our model to be stable and realistic. From the graphical representations the impact of the coupling constant and the parameter of the DP metric potential are clearly visible. Thus we can state that with all the above-mentioned features we have introduced new stellar solutions for BEC stars with enhanced precise results in this modified gravity.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"50 ","pages":"Article 100486"},"PeriodicalIF":10.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2026-02-01Epub Date: 2025-09-24DOI: 10.1016/j.jheap.2025.100483
Rahul Bhagat, B. Mishra
We have performed the dynamical system analysis to obtain the critical point in which, the value of the geometric and dynamical parameters satisfy the late-time cosmic behavior of the Universe. At the outset, the modified Friedmann equations have been reformulated into a system of coupled differential equations to ensure that the minimal set of equations required for a second-order gravity. Then these equations are solved numerically to constrain the parameters with Markov Chain Monte Carlo (MCMC) techniques. Cosmic Chronometers (CC) and high-precision Pantheon+ Type Ia Supernovae datasets are used to constrain the parameters. The evolution of key cosmological parameters indicates that the model exhibits quintessence-like behavior at present, with a tendency to converge towards the ΛCDM model at late-times. The dynamic system analysis provided the critical points that correspond to different phases of the Universe, which are analyzed in detail. The existence of a stable de Sitter attractor confirms the accelerating behavior of the model.
{"title":"Accelerating behavior from dynamical system analysis parameters","authors":"Rahul Bhagat, B. Mishra","doi":"10.1016/j.jheap.2025.100483","DOIUrl":"10.1016/j.jheap.2025.100483","url":null,"abstract":"<div><div>We have performed the dynamical system analysis to obtain the critical point in which, the value of the geometric and dynamical parameters satisfy the late-time cosmic behavior of the Universe. At the outset, the modified Friedmann equations have been reformulated into a system of coupled differential equations to ensure that the minimal set of equations required for a second-order <span><math><mi>f</mi><mo>(</mo><mi>Q</mi><mo>)</mo></math></span> gravity. Then these equations are solved numerically to constrain the parameters with Markov Chain Monte Carlo (MCMC) techniques. Cosmic Chronometers (CC) and high-precision Pantheon<sup>+</sup> Type Ia Supernovae datasets are used to constrain the parameters. The evolution of key cosmological parameters indicates that the model exhibits quintessence-like behavior at present, with a tendency to converge towards the ΛCDM model at late-times. The dynamic system analysis provided the critical points that correspond to different phases of the Universe, which are analyzed in detail. The existence of a stable de Sitter attractor confirms the accelerating behavior of the model.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"50 ","pages":"Article 100483"},"PeriodicalIF":10.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}