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International Journal of Modern Physics D最新文献

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Confronting the Chaplygin gas with data: background and perturbed cosmic dynamics 用数据面对Chaplygin气体:背景和扰动的宇宙动力学
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-11-07 DOI: 10.1142/s0218271823500906
Shambel Sahlu, Heba Sami, Renier Hough, Maye Elmardi, Anna-Mia Swart, Amare Abebe
{"title":"Confronting the Chaplygin gas with data: background and perturbed cosmic dynamics","authors":"Shambel Sahlu, Heba Sami, Renier Hough, Maye Elmardi, Anna-Mia Swart, Amare Abebe","doi":"10.1142/s0218271823500906","DOIUrl":"https://doi.org/10.1142/s0218271823500906","url":null,"abstract":"In this paper, we undertake a unified study of background dynamics and cosmological perturbations in the presence of the Chaplygin gas (CG). This is done by first constraining the background cosmological parameters of different Chaplygin gas models with SNeIa and [Formula: see text] data for detailed statistical analysis of the CG models. Based on the statistical criteria we followed, none of the models has substantial observational support, but we show that the so-called “original” and “extended/generalised” Chaplygin gas models have some observational support and less observational support, respectively, whereas the “modified” and “modified generalised” Chaplygin gas models miss out on the category less observational support, but cannot be ruled out. The so-called “generalised” cosmic Chaplygin gas model, on the other hand, falls under the no observational support category of the statistical criterion and can be ruled out. The models which are statistically accepted are considered for perturbation level in both theoretical and observational aspects. We also apply the [Formula: see text] covariant formalism of perturbation theory and derive the evolution equations of the fluctuations in the matter density contrast of the matter–Chaplygin gas system for the models with some or less statistical support. The solutions to these coupled systems of equations are then computed in both short-wavelength and long-wavelength modes. Then we feed these observationally restricted parameters into the analysis of cosmological perturbations to address the growth of density contrast through redshift. Using the most recent linear growth of the data [Formula: see text], CG models are considered to study the linear growth of the structure.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135432005","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}
引用次数: 3
Smooth extensions of black holes in loop quantum gravity 环量子引力中黑洞的平滑延伸
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-11-03 DOI: 10.1142/s0218271823501018
Rodolfo Gambini, Javier Olmedo, Jorge Pullin
{"title":"Smooth extensions of black holes in loop quantum gravity","authors":"Rodolfo Gambini, Javier Olmedo, Jorge Pullin","doi":"10.1142/s0218271823501018","DOIUrl":"https://doi.org/10.1142/s0218271823501018","url":null,"abstract":"Vacuum spherically symmetric loop quantum gravity in the midi-superspace approximation using inhomogeneous horizon-penetrating slices has been studied for a decade, and it has been noted that the singularity is eliminated. It is replaced by a region of high curvature and potentially large quantum fluctuations. It was recently pointed out that the effective semiclassical metric implies the existence of a shell of effective matter which violates energy conditions in regions where the curvature is largest. Here we propose an alternative way of treating the problem that is free from the shells. The ambiguity in the treatment is related with the existence of new observables in the quantum theory that characterize the area excitations, and how the counterpart of diffeomorphisms in the discrete quantum theory is mapped to the continuum semi-classical picture. The resulting space-time in the high curvature region inside the horizon is approximated by a metric of the type of the Simpson--Visser wormhole and it connects the black hole interior to a white hole in a smooth manner.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135868807","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}
引用次数: 0
Analytical Models of Hyperbolical Gravitational Sources 双曲型引力源的解析模型
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-11-01 DOI: 10.1142/s021827182350089x
Z. Yousaf, M. Z. Bhattti, H. Asad
{"title":"Analytical Models of Hyperbolical Gravitational Sources","authors":"Z. Yousaf, M. Z. Bhattti, H. Asad","doi":"10.1142/s021827182350089x","DOIUrl":"https://doi.org/10.1142/s021827182350089x","url":null,"abstract":"This paper aims to conduct an extensive examination of hyperbolically symmetrical static fluid distributions, wherein a precise analysis of their physical characteristics is carried out in the background of modified [Formula: see text] gravity, where [Formula: see text] and [Formula: see text] stands for Gauss Bonnet invariant and energy-momentum trace, respectively. The outcomes reveal that the energy density exhibits negative value, thus implying that any utilization of such fluids necessitates extremely demanding circumstances where quantum effects would be significantly influential. Furthermore, it has been determined that these fluid distributions cannot take the vicinity surrounding their central point of symmetry and leave behind an empty vacuum cavity in its place. Additionally, an appropriate definition for mass function and the complexity factor is determined. Eventually, we exhibit a broad strategy for accomplishing particular solutions and showcase several instances of exact analytical solutions in the presence of [Formula: see text] correction terms.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135011743","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}
引用次数: 0
Black Holes, Equilibrium, and Cosmology 黑洞、平衡和宇宙学
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-28 DOI: 10.1142/s0218271823420233
Fil Simovic
{"title":"Black Holes, Equilibrium, and Cosmology","authors":"Fil Simovic","doi":"10.1142/s0218271823420233","DOIUrl":"https://doi.org/10.1142/s0218271823420233","url":null,"abstract":"We trace the origins and development of black hole thermodynamics across the past half-century, emphasizing the framework’s relation to classical thermodynamics, and the vital role played by the notions of equilibrium, stationarity and symmetry. We discuss different interpretations of the first law of black hole mechanics, and assess the validity of its mechanical, process-based interpretation for evaporating black holes. We bring these ideas to the cosmological realm, and highlight the various difficulties that arise when formulating thermodynamics for black holes in asymptotically de Sitter backgrounds. We discuss a number of proposed solutions and the open questions that arise therein.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136157331","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}
引用次数: 0
The trustees are pleased to announce the Awards for Essays for 2023 受托人很高兴地宣布2023年论文奖
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-28 DOI: 10.1142/s0218271823020029
{"title":"The trustees are pleased to announce the Awards for Essays for 2023","authors":"","doi":"10.1142/s0218271823020029","DOIUrl":"https://doi.org/10.1142/s0218271823020029","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136232743","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}
引用次数: 0
Cosmographic and Phase Space Analysis of Dynamical Chern-Simons Modified and Fractal Gravities 动态chen - simons修正和分形引力的宇宙学和相空间分析
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-27 DOI: 10.1142/s0218271823501006
Muhammad Usman, Abdul Jawad
{"title":"Cosmographic and Phase Space Analysis of Dynamical Chern-Simons Modified and Fractal Gravities","authors":"Muhammad Usman, Abdul Jawad","doi":"10.1142/s0218271823501006","DOIUrl":"https://doi.org/10.1142/s0218271823501006","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136261568","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}
引用次数: 0
Holographic description of the dissipative unified dark fluid model with axion field 具有轴子场的耗散统一暗流体模型的全息描述
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-27 DOI: 10.1142/s0218271823500852
I. Brevik, A. V. Timoshkin
{"title":"Holographic description of the dissipative unified dark fluid model with axion field","authors":"I. Brevik, A. V. Timoshkin","doi":"10.1142/s0218271823500852","DOIUrl":"https://doi.org/10.1142/s0218271823500852","url":null,"abstract":"In this paper, we extend an axion [Formula: see text] gravity model, and apply the holographic principle to describe in a unifying manner the early and the late-time universe when the general equation-of-state (EoS) contains a bulk viscosity. We assume a spatially flat Friedmann–Robertson–Walker (FRW) universe model. We use a description based on the generalized infrared-cutoff holographic dark energy proposed by Nojiri and Odintsov [Eur. Phys. J. C 77 (2017) 528; Gen. Relativ. Gravit. 38 (2006) 1285], and explore the evolution of the universe when the EoS describes the asymptotic behavior between the dust in the early universe and the late universe. We explore various forms of the bulk viscosity, and calculate analytical expressions for the infrared cutoffs in terms of the particle horizon. In this way, we obtain a unifying description of the early and the late-time universe in the presence of axion matter, via a viscous holographic fluid model.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136233156","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}
引用次数: 0
Quintessential Inflation and curvaton reheating 典型的膨胀和曲率再加热
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-21 DOI: 10.1142/s021827182350092x
Abhineet Agarwal, Sabit Bekov, Kairat Myrzakulov
{"title":"Quintessential Inflation and curvaton reheating","authors":"Abhineet Agarwal, Sabit Bekov, Kairat Myrzakulov","doi":"10.1142/s021827182350092x","DOIUrl":"https://doi.org/10.1142/s021827182350092x","url":null,"abstract":"In this paper, we consider a model of quintessential inflation based upon inverse hyperbolic potential. We employ curvaton mechanism for reheating which is more efficient than gravitational particle production; the mechanism complies with nucleosynthesis constraint due to relic gravity waves. We obtain a lower bound on the coupling constant [Formula: see text] that governs the interaction of curvaton with matter fields. We study curvaton decay before domination and decay after domination and plot the allowed region in the parameter space in both cases.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135463809","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}
引用次数: 3
Stability and pair production of scalars in the charged Einstein-ModMax black hole spacetime 带电爱因斯坦- modmax黑洞时空中标量的稳定性和对产生
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-20 DOI: 10.1142/s0218271823500992
Haryanto M. Siahaan
{"title":"Stability and pair production of scalars in the charged Einstein-ModMax black hole spacetime","authors":"Haryanto M. Siahaan","doi":"10.1142/s0218271823500992","DOIUrl":"https://doi.org/10.1142/s0218271823500992","url":null,"abstract":"","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135567074","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}
引用次数: 0
General formulae for the periapsis shift of a quasi-circular orbit in static spherically symmetric spacetimes and the active gravitational mass density 静态球对称时空中准圆轨道近点位移和活动重力质量密度的一般公式
4区 物理与天体物理
International Journal of Modern Physics D Pub Date : 2023-10-20 DOI: 10.1142/s0218271823500980
Tomohiro Harada, Takahisa Igata, Hiromi Saida, Yohsuke Takamori
{"title":"General formulae for the periapsis shift of a quasi-circular orbit in static spherically symmetric spacetimes and the active gravitational mass density","authors":"Tomohiro Harada, Takahisa Igata, Hiromi Saida, Yohsuke Takamori","doi":"10.1142/s0218271823500980","DOIUrl":"https://doi.org/10.1142/s0218271823500980","url":null,"abstract":"We study the periapsis shift of a quasi-circular orbit in general static spherically symmetric spacetimes. We derive two formulae in full order with respect to the gravitational field, one in terms of the gravitational mass $m$ and the Einstein tensor and the other in terms of the orbital angular velocity and the Einstein tensor. These formulae reproduce the well-known ones for the forward shift in the Schwarzschild spacetime. In a general case, the shift deviates from that in the vacuum spacetime due to a particular combination of the components of the Einstein tensor at the radius $r$ of the orbit. The formulae give a backward shift due to the extended-mass effect in Newtonian gravity. In general relativity, in the weak-field and diffuse regime, the active gravitational mass density, $rho_{A}=(epsilon+p_{r}+2p_{t})/c^{2}$, plays an important role, where $epsilon$, $p_{r}$, and $p_{t}$ are the energy density, the radial stress, and the tangential stress of the matter field, respectively. We show that the shift is backward if $rho_{A}$ is beyond a critical value $rho_{c}simeq 2.8times 10^{-15} mbox{g}/mbox{cm}^{3} (m/M_{odot})^{2}(r/mbox{au})^{-4}$, while a forward shift greater than that in the vacuum spacetime instead implies $rho_{A}<0$, i.e., the violation of the strong energy condition, and thereby provides evidence for dark energy. We obtain new observational constraints on $rho_{A}$ in the Solar System and the Galactic Centre.","PeriodicalId":50307,"journal":{"name":"International Journal of Modern Physics D","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135566613","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}
引用次数: 0
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