Physics of the Dark Universe最新文献

{"title":"Fuzzy dark matter fails to explain dark matter cores","authors":"María Benito ,&nbsp;Gert Hütsi ,&nbsp;Kristjan Müürsepp ,&nbsp;Jorge Sánchez Almeida ,&nbsp;Juan Urrutia ,&nbsp;Ville Vaskonen ,&nbsp;Hardi Veermäe","doi":"10.1016/j.dark.2025.102010","DOIUrl":"10.1016/j.dark.2025.102010","url":null,"abstract":"<div><div>Ultrafaint dwarf galaxies (UFDs) are ideal for studying dark matter (DM) due to minimal baryonic effects. UFD observations suggest cored DM profiles. We find that the core radius–stellar mass scaling predicted by fuzzy dark matter (FDM) is at <span><math><mrow><mn>6</mn><mo>.</mo><mn>1</mn><mi>σ</mi></mrow></math></span> tension with UFD observations. Combining observations from 27 UFDs, the required FDM mass <span><math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>=</mo><mn>3</mn><mo>.</mo><msubsup><mrow><mn>2</mn></mrow><mrow><mo>−</mo><mn>0</mn><mo>.</mo><mn>6</mn></mrow><mrow><mo>+</mo><mn>0</mn><mo>.</mo><mn>8</mn></mrow></msubsup><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>21</mn></mrow></msup><mspace></mspace><mi>eV</mi></mrow></math></span> is also in conflict with existing Lyman-<span><math><mi>α</mi></math></span> bounds. Our results suggest that FDM cannot provide a consistent explanation for DM cores and imply <span><math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>&gt;</mo><mn>2</mn><mo>.</mo><mn>2</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>21</mn></mrow></msup><mspace></mspace><mi>eV</mi></mrow></math></span> at to <span><math><mrow><mn>2</mn><mi>σ</mi></mrow></math></span> CL.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102010"},"PeriodicalIF":5.0,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144634481","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}

{"title":"Optical signatures of hairy black holes surrounded by plasma: Shadows and weak lensing","authors":"Abduqodir Bakhodirov ,&nbsp;Bakhodir Shodikulov ,&nbsp;Farruh Atamurotov ,&nbsp;Ahmadjon Abdujabbarov ,&nbsp;Chen Zhou ,&nbsp;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}

{"title":"Dynamical analysis of quantum matter bounces with dark sector mimickers","authors":"Francisco Bento Lustosa,&nbsp;Nelson Pinto-Neto","doi":"10.1016/j.dark.2025.102013","DOIUrl":"10.1016/j.dark.2025.102013","url":null,"abstract":"<div><div>We study the effects of the inclusion of fluids In bounce scenarios driven by an exponential potential scalar field. Most solutions exhibit well known tracking behavior between the fluids and the scalar field. This tracking behavior can model transitions between different phases of cosmic evolution. We will focus on an interesting bouncing model with a dust matter fluid, where the scalar field can drive an early dark energy expanding period with a radiation-like dominated phase just after it, and then tracks the dust matter fluid with energy density compatible with the dark matter energy density. The model is dust dominated in the far past of the contracting phase, and has stiff matter behavior when approaching the singularity, allowing well known quantum bounce transitions to the expanding era. Hence, it is a quantum matter bounce scenario with an inflationary phase together with a smooth transition through a radiation era to matter domination with a possible scalar field dark matter candidate.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102013"},"PeriodicalIF":5.0,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631188","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}

{"title":"Attempting to circumvent the Ricci-inverse no-go theorem with complexifiable singularities: An emergent Dark Energy model","authors":"Mattia Scomparin","doi":"10.1016/j.dark.2025.102002","DOIUrl":"10.1016/j.dark.2025.102002","url":null,"abstract":"<div><div>Ricci-inverse gravity is a new type of fourth-order gravity theory based on the anti-curvature tensor, that is, the inverse of the Ricci tensor. In this context, we introduce a novel method to circumvent the binding effects of a well-known no-go theorem for cosmic trajectories that cannot smoothly join a decelerated cosmic age with the current accelerated expansion of the universe. We therefore design an emergent class of Ricci-inverse theories whose cosmologies, without falling into no-go singularities, achieve the observed expansion as a stable attractor solution. This new perspective retrains Ricci-inverse cosmologies as viable dark energy models.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102002"},"PeriodicalIF":5.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655802","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}

{"title":"Neutrino oscillation measurements with KamLAND and JUNO in the presence of scalar NSI","authors":"Aman Gupta ,&nbsp;Debasish Majumdar ,&nbsp;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}

{"title":"Strong lensing effect and quasinormal modes of oscillations of black holes in f(R,T) gravity theory","authors":"Gayatri Mohan,&nbsp;Ronit Karmakar,&nbsp;Rupam Jyoti Borah,&nbsp;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}

{"title":"Resilience and implications of adiabatic CMB cooling","authors":"Ruchika ,&nbsp;William Giarè ,&nbsp;Elsa M. Teixeira ,&nbsp;Alessandro Melchiorri","doi":"10.1016/j.dark.2025.101999","DOIUrl":"10.1016/j.dark.2025.101999","url":null,"abstract":"&lt;div&gt;&lt;div&gt;We investigate potential deviations from the standard adiabatic evolution of the cosmic microwave background (CMB) temperature, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;CMB&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, using the latest Sunyaev-Zeldovich (SZ) effect measurements and molecular line excitation data, covering a combined redshift range of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;≲&lt;/mo&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. We follow different approaches. First, we reconstruct the redshift evolution of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;CMB&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; in a model-independent way using Gaussian Process regression. The tightest constraints come from SZ measurements at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, while molecular line data at &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;&gt;&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; yield broader uncertainties. By combining both datasets, we find good consistency with the standard evolution across the full analysed redshift range, inferring a present-day CMB monopole temperature of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;744&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;019&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; K. Next, we test for deviations from the standard scaling by adopting the parametrisation &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;CMB&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;z&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, where &lt;span&gt;&lt;math&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; quantifies departures from adiabaticity, with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; corresponding to the standard scenario. In this framework, we use Gaussian Process reconstruction to test the consistency of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; across the full redshift range and perform &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; minimisation techniques to determine the best-fit values of &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;. In both cases, we find good consistency with the standard temperature-redshift relation. The &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;-minimisation analysis yields best-fit values of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;β&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0106&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0124&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;.&lt;","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 101999"},"PeriodicalIF":5.0,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144596643","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}

{"title":"Could planck star remnants be dark matter?","authors":"Oem Trivedi ,&nbsp;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}

{"title":"Quantum phase transitions of Dirac particles in a magnetized rotating curved background: Interplay of geometry, magnetization, and thermodynamics","authors":"Nusret Sahan ,&nbsp;Erdem Sucu ,&nbsp;Yusuf Sucu","doi":"10.1016/j.dark.2025.102005","DOIUrl":"10.1016/j.dark.2025.102005","url":null,"abstract":"<div><div>In this research, we investigate the quantum and classical phase transitions of the Dirac particles in a homogeneously magnetized curved rotating 2+1 dimensional spacetime. We consider the intricate relationship between geometry and quantum phase events through the study of quantum electrodynamics in the rotating curved spacetime. Using methods from quantum electrodynamics and statistical mechanics, the study examines the effects of an external magnetic field, the background rotation parameter, and curvature on the characteristics of quantum and classical phase transitions, focusing on critical points and scaling behavior, and we see that as thermal fluctuations get closer to zero, quantum fluctuations begin to dominate at this system.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102005"},"PeriodicalIF":5.0,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570166","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}

{"title":"Analogue of Chern–Simons invariant in non-metricity gravity and axion cosmology","authors":"Shin’ichi Nojiri ,&nbsp;Sergei D. Odintsov","doi":"10.1016/j.dark.2025.102001","DOIUrl":"10.1016/j.dark.2025.102001","url":null,"abstract":"<div><div>We propose a pseudo-scalar quantity, which is an analogue of the Chern–Simons invariant, in the framework of non-metricity gravity. By considering the coupling between the pseudo-scalar quantity and the axion, we give scenarios which may solve the problems of the axion misalignment, the <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>8</mn></mrow></msub></math></span> problem, and the beginning of inflation. When the phase transition associated with the spontaneous breaking of the gauge symmetry of the electroweak theory or grand unified theories (GUTs) occurs, the pseudo-scalar quantity has a non-trivial value, which induces the misalignment of the axion field and axion particles are produced. If the gradient of the potential is small, the <span><math><msub><mrow><mi>S</mi></mrow><mrow><mn>8</mn></mrow></msub></math></span> problem might be solved. We also propose a mechanism which induces inflation by the misalignment of the axion field generated by the phase transition of the GUTs.</div></div>","PeriodicalId":48774,"journal":{"name":"Physics of the Dark Universe","volume":"49 ","pages":"Article 102001"},"PeriodicalIF":5.0,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570717","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}