Physics of the Dark Universe最新文献

Probing black hole evolution through homogeneous gravitational collapse in f(Q) gravity 通过f(Q)引力的均匀坍缩探测黑洞演化

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-18 DOI: 10.1016/j.dark.2025.102020

Shubham Sharma , Rajesh Kumar , Shibesh Kumar Jas Pacif

{"title":"Probing black hole evolution through homogeneous gravitational collapse in f(Q) gravity","authors":"Shubham Sharma , Rajesh Kumar , Shibesh Kumar Jas Pacif","doi":"10.1016/j.dark.2025.102020","DOIUrl":"10.1016/j.dark.2025.102020","url":null,"abstract":"<div><div>In this study, we investigate black hole (BH) formation resulting from the gravitational collapse of self-gravitating systems within the context of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity. This work addresses key unresolved issues in theoretical physics regarding the end stage of gravitational collapse in massive stars. Building on the foundational research of Oppenheimer and Snyder (1939), we analyze a homogeneous collapsing system with perfect fluid distributions under <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow><mo>=</mo><mi>Q</mi><mo>+</mo><mi>α</mi><msup><mrow><mi>Q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> gravity theory. To achieve this, we consider a homogeneous collapsing system with a spherically symmetric space–time geometry described by the FLRW metric with prefect fluid matter distribution. We have also discussed the junction conditions <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> theory. By employing a parametrization of the expansion scalar, we derive an exact, model-independent solution to the Einstein field equations for the collapsing system. To explore the physical viability of the model we consider some known massive stars- <span><math><mrow><mi>R</mi><mn>136</mn><mi>a</mi><mn>3</mn><mo>,</mo><mi>R</mi><mn>136</mn><mi>c</mi></mrow></math></span>, and <span><math><mrow><mi>R</mi><mn>99</mn></mrow></math></span> with their known astrophysical stellar data (masses and radii). We discuss the formation of apparent horizon and space–time singularity, which further predicts BH as the final state of these collapsing stars. Additionally, we calculate the lifespans of these stellar objects, showing that higher-mass stars have shorter lifespans compared to less massive stars. We have also applied various test, including energy conditions, the equation of state, and stability criteria, and the adiabatic index. We have also presented a comparative analysis of our solution with standard Einstein’s General Relativity.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102020"},"PeriodicalIF":5.0,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672113","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}

引用次数: 0

Analytical polyΛCDM dynamics 分析polyΛCDM动力学

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-16 DOI: 10.1016/j.dark.2025.101985

Pierros Ntelis , Jackson Levi Said

{"title":"Analytical polyΛCDM dynamics","authors":"Pierros Ntelis , Jackson Levi Said","doi":"10.1016/j.dark.2025.101985","DOIUrl":"10.1016/j.dark.2025.101985","url":null,"abstract":"<div><div>In this paper, we study the <span><math><mi>ϕ</mi></math></span>CDM and the <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM models and compare them to the standard concordance model, the vanilla <span><math><mi>Λ</mi></math></span>CDM.</div><div>Analytical solutions for the <span><math><mi>ϕ</mi></math></span>CDM model, vital for precision, show sub-% agreement with <span><math><mi>Λ</mi></math></span>CDM due to selected energy density components, yet larger differences from numerical solutions of the same equations underscore their reliability over numerical integration of stiff systems.</div><div>The <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM model is a phenomenological modified gravity model. We analyse their respective epoch evolutions, perform a detailed analytical and numerical dynamical analysis for each, and conduct a comparative study between the frameworks. Our work revitalizes these models by incorporating systems with an expanded set of variables, enabling us to derive analytical expressions for the energy density ratios of all species in both models. Moreover, the <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM model we present is both more comprehensive and streamlined compared to existing studies. It captures all known cosmic epochs, including radiation, matter, and dark energy phases, and more exotic ones. The <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM model has the cosmological constant term dominance in the far future epoch.</div><div>For the <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM model, we find <em>the global transition from a pure reflector of the dark energy dark matter exchange dominant component, to the saddle reflector points of matter, radiation, curvature, modified gravity components, and then we transit to the SVT modified gravity component attractor-saddle epoch, which also transits to the final cosmological constant, attractor epoch, in the far future. Note that there is saddle transition between the modified gravity dominant component and the SVT modified gravity component. Note that there is saddle transition between the SVT modified gravity and the cosmological constant component in the far future.</em></div><div>Our findings show that all three models effectively describe the widely accepted cosmic evolution scenario and align with current observations. While all <span><math><mi>Λ</mi></math></span>CDM, <span><math><mi>ϕ</mi></math></span>CDM, and <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM reproduce the qualitative and quantitative behaviour of the universe’s species across epochs, the <span><math><mrow><mi>p</mi><mi>o</mi><mi>l</mi><mi>y</mi><mi>Λ</mi></mrow></math></span>CDM model exhibits a richer phenomenology, ","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 101985"},"PeriodicalIF":5.0,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655801","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}

引用次数: 0

Fuzzy dark matter fails to explain dark matter cores 模糊暗物质无法解释暗物质核

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-12 DOI: 10.1016/j.dark.2025.102010

María Benito , Gert Hütsi , Kristjan Müürsepp , Jorge Sánchez Almeida , Juan Urrutia , Ville Vaskonen , Hardi Veermäe

引用次数: 0

Optical signatures of hairy black holes surrounded by plasma: Shadows and weak lensing 被等离子体包围的毛茸茸黑洞的光学特征：阴影和弱透镜效应

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-12 DOI: 10.1016/j.dark.2025.102008

Abduqodir Bakhodirov , Bakhodir Shodikulov , Farruh Atamurotov , Ahmadjon Abdujabbarov , Chen Zhou , Chengxun Yuan

{"title":"Optical signatures of hairy black holes surrounded by plasma: Shadows and weak lensing","authors":"Abduqodir Bakhodirov , Bakhodir Shodikulov , Farruh Atamurotov , Ahmadjon Abdujabbarov , Chen Zhou , Chengxun Yuan","doi":"10.1016/j.dark.2025.102008","DOIUrl":"10.1016/j.dark.2025.102008","url":null,"abstract":"<div><div>The optical properties around the hairy black hole have been studied in the presence of a plasma medium. The obtained results have shown that the effect of the hairy black hole parameter’s <span><math><mi>a</mi></math></span>, <span><math><msub><mrow><mi>l</mi></mrow><mrow><mi>o</mi></mrow></msub></math></span> and <span><math><mi>Q</mi></math></span> on the deflection angle of light rays around the black hole is perceptible. With an increase in hairs <span><math><mi>a</mi></math></span> and <span><math><msub><mrow><mi>l</mi></mrow><mrow><mi>o</mi></mrow></msub></math></span> of black hole, there is a promotion in the radius of the photon sphere and the radius of the shadow of the central object. However, an increase in primary hair <span><math><mi>Q</mi></math></span> leads to a reduction in the photon sphere and shadow of the hairy black hole, and the effect of plasma on the deflection angle is the opposite. Here, we discuss different types of plasma distributions: uniform <span><math><mrow><msub><mrow><mi>ω</mi></mrow><mrow><mi>e</mi></mrow></msub><mo>=</mo><mi>c</mi><mi>o</mi><mi>n</mi><mi>s</mi><mi>t</mi></mrow></math></span>; Singular Isothermal Sphere medium and nonuniform plasma with <span><math><mrow><msubsup><mrow><mi>ω</mi></mrow><mrow><mi>e</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>=</mo><msub><mrow><mi>z</mi></mrow><mrow><mi>o</mi></mrow></msub><mo>/</mo><mi>r</mi></mrow></math></span>. Additionally, the total magnification of the image source due to the gravitational weak lensing has also been considered taking into account the influence of parameters <span><math><mi>a</mi></math></span>, <span><math><msub><mrow><mi>l</mi></mrow><mrow><mi>o</mi></mrow></msub></math></span> and <span><math><mi>Q</mi></math></span> related to hairy spacetime in the presence of plasma around the black hole.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102008"},"PeriodicalIF":5.0,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631189","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}

引用次数: 0

Dynamical analysis of quantum matter bounces with dark sector mimickers 暗扇区模拟器对量子物质弹跳的动力学分析

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-11 DOI: 10.1016/j.dark.2025.102013

Francisco Bento Lustosa, Nelson Pinto-Neto

引用次数: 0

Attempting to circumvent the Ricci-inverse no-go theorem with complexifiable singularities: An emergent Dark Energy model 试图用可复化奇点来规避里奇逆不去定理：一个涌现的暗能量模型

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-10 DOI: 10.1016/j.dark.2025.102002

Mattia Scomparin

引用次数: 0

Neutrino oscillation measurements with KamLAND and JUNO in the presence of scalar NSI 卡姆兰和朱诺在标量NSI存在下的中微子振荡测量

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-10 DOI: 10.1016/j.dark.2025.102011

Aman Gupta , Debasish Majumdar , Suprabh Prakash

{"title":"Neutrino oscillation measurements with KamLAND and JUNO in the presence of scalar NSI","authors":"Aman Gupta , Debasish Majumdar , Suprabh Prakash","doi":"10.1016/j.dark.2025.102011","DOIUrl":"10.1016/j.dark.2025.102011","url":null,"abstract":"<div><div>Determination of neutrino mass ordering and precision measurement of neutrino oscillation parameters are the foremost goals of the JUNO experiment. Here, we explore the effects of scalar non-standard interactions (sNSI) on the electron anti-neutrino survival probability measured by JUNO. sNSI appear as corrections to the neutrino mass term in the Hamiltonian. We have considered the simplest scenario where there is only one NSI (<span><math><msub><mrow><mi>η</mi></mrow><mrow><mi>e</mi><mi>e</mi></mrow></msub></math></span>) present in the theory. Our results show that sNSI can have a significant effect on neutrino oscillation probabilities at the medium- and long-baseline reactor experiments. We fit KamLAND data assuming non-zero sNSI in theory and find that <em>estimates of</em> <span><math><mrow><mi>Δ</mi><msubsup><mrow><mi>m</mi></mrow><mrow><mn>21</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mspace></mspace></mrow></math></span><em>and</em> <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mn>12</mn></mrow></msub></math></span> <em>from KamLAND deviate significantly from their standard best-fit values</em> if one assumes sNSI in the theory. <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mi>e</mi><mi>e</mi></mrow></msub><mo>∈</mo><mrow><mo>[</mo><mo>−</mo><mn>1</mn><mo>.</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>.</mo><mn>0</mn><mo>]</mo></mrow></mrow></math></span> is allowed by KamLAND. JUNO cannot constrain sNSI but it can robustly measure <span><math><mrow><mi>Δ</mi><msubsup><mrow><mi>m</mi></mrow><mrow><mn>21</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mspace></mspace></mrow></math></span>and <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mn>12</mn></mrow></msub></math></span> even when they differ widely from their current best-fit values. <em>Our work highlights the necessity of global analysis of constraints on sNSI and standard two-flavour oscillation parameters before arduous three-flavour questions such as neutrino mass ordering or CP violation in their presence are attempted.</em></div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102011"},"PeriodicalIF":5.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614253","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}

引用次数: 0

Strong lensing effect and quasinormal modes of oscillations of black holes in f(R,T) gravity theory f（R，T）引力理论中黑洞的强透镜效应和准正态振荡模式

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-09 DOI: 10.1016/j.dark.2025.102007

Gayatri Mohan, Ronit Karmakar, Rupam Jyoti Borah, Umananda Dev Goswami

{"title":"Strong lensing effect and quasinormal modes of oscillations of black holes in f(R,T) gravity theory","authors":"Gayatri Mohan, Ronit Karmakar, Rupam Jyoti Borah, Umananda Dev Goswami","doi":"10.1016/j.dark.2025.102007","DOIUrl":"10.1016/j.dark.2025.102007","url":null,"abstract":"<div><div>In this work, we analyze the strong lensing phenomenon and quasinormal modes (QNMs) in the case of black holes (BHs) surrounded by fluids within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity, adopting a minimally coupled model of the theory. Our analysis is conducted for three surrounding fields corresponding to three different values of the parameter <span><math><mi>ω</mi></math></span> of the equations of state, each representing a unique class of BH solutions. A universal method developed by V. Bozza is employed for strong lensing analysis and the WKB approximation method to compute the QNMs of oscillation of the BHs. The influences of the model parameters <span><math><mi>β</mi></math></span> and <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> on the deflection angle and associated lensing coefficients are analyzed. Our findings on lensing reveal that smaller values of <span><math><mi>β</mi></math></span> and <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> cause photon divergence at larger impact parameters as well as the lensing results converge to the Schwarzschild limit. Extending the analysis to the supermassive BH Sgr A*, we examine the outermost Einstein rings, estimate three lensing observables: angular position <span><math><msub><mrow><mi>ϑ</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span>, angular separation <span><math><mi>s</mi></math></span> and relative magnification <span><math><msub><mrow><mi>r</mi></mrow><mrow><mtext>mag</mtext></mrow></msub></math></span> for the BHs. For a specific values of <span><math><mi>β</mi></math></span> and <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, BHs with different field configurations exhibit substantial variations in their observable properties. The variation of amplitude and damping of QNMs with respect to the model parameter <span><math><mi>β</mi></math></span> and <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> is analyzed for the BHs. We found that the <span><math><mi>β</mi></math></span> parameter has a direct correlation with the amplitude and an inverse relation with the damping of the QNMs, while <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> has direct correlation with amplitude as well as damping. Further, we use the time domain analysis to verify the results and found a good match between the two methods.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102007"},"PeriodicalIF":5.0,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589174","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}

引用次数: 0

Resilience and implications of adiabatic CMB cooling 微波背景绝热冷却的回弹性及其意义

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-07 DOI: 10.1016/j.dark.2025.101999

Ruchika , William Giarè , Elsa M. Teixeira , Alessandro Melchiorri

引用次数: 0

Could planck star remnants be dark matter? 普朗克恒星残余物可能是暗物质吗？

IF 5 2区物理与天体物理

Physics of the Dark Universe Pub Date : 2025-07-05 DOI: 10.1016/j.dark.2025.102003

Oem Trivedi , Abraham Loeb

{"title":"Could planck star remnants be dark matter?","authors":"Oem Trivedi , Abraham Loeb","doi":"10.1016/j.dark.2025.102003","DOIUrl":"10.1016/j.dark.2025.102003","url":null,"abstract":"<div><div>We explore the end state of gravitational collapse under quantum gravity effects and propose that Planck Star Remnants (PSR), formed via nonsingular bounces, could serve as viable dark matter candidates. Within the framework of Loop Quantum Cosmology, we model the collapse of a homogeneous matter distribution and show that the classical singularity is replaced by a quantum bounce at the Planck density. By analytically matching the Friedman–Lemaître–Robertson–Walker (FLRW) interior to an exterior Schwarzschild spacetime using the Israel junction conditions, we demonstrate that the bounce remains causally hidden from external observers, avoiding any observable re-expansion. This naturally leads to the formation of stable, non-radiating PSR, whose radius coincides with the Schwarzschild radius when the black hole mass approaches the Planck mass as a result of Hawking evaporation. We suggest that such remnants may originate from evaporating primordial black holes in the early universe, and estimate the relic abundance needed for PSR to account for the observed dark matter density. We also discuss some crucial differences between PSR and previous proposals of Planck mass relics. The scenario is shown to be consistent with existing astrophysical and cosmological constraints, offering a unified framework connecting quantum gravitational collapse, and the nature of dark matter.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102003"},"PeriodicalIF":5.0,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655800","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}

引用次数: 0