The European Physical Journal C最新文献

{"title":"Stability bounds on inflationary initial states from UV–IR reflection on a trans-Planckian band","authors":"Douglas F. Watson,&nbsp;Tiziano Valentinuzzi","doi":"10.1140/epjc/s10052-026-15681-5","DOIUrl":"10.1140/epjc/s10052-026-15681-5","url":null,"abstract":"<div><p>We derive model-independent constraints on finite-time inflationary initial states by combining an EFT with physical cutoff <span>(Lambda )</span>, backreaction control at the initialization time, and a UV–IR reflection principle imposed only on a logarithmic “trans-Planckian band” about the cutoff pivot. For Gaussian, homogeneous and isotropic states, Bogoliubov data <span>(beta _k)</span> determine the excitation energy density, and backreaction finiteness selects a natural weighted Hilbert norm on this data. We introduce a windowed symmetry defect on the band and an explicit local completion map that enforces the reflection without constraining modes outside the band. Requiring that completion does not move admissible data by an order-one amount in the backreaction norm yields a parametric lower bound on the excitation energy density in terms of cutoff-scale Bogoliubov jets. In the narrow-band regime the defect admits a universal jet expansion, so generic non–Bunch–Davies data require tuned cancellations among cutoff derivatives or a nonzero excitation floor.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15681-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmological dynamics of exponential quintessence constrained by BAO, cosmic chronometers, and DES-SN5YR/Pantheon(^+) data","authors":"Sanjeeda Sultana,&nbsp;Surajit Chattopadhyay","doi":"10.1140/epjc/s10052-026-15672-6","DOIUrl":"10.1140/epjc/s10052-026-15672-6","url":null,"abstract":"<div><p>We perform a comprehensive observational test of a canonical quintessence model driven by an exponential potential, motivated by its emergence in higher-dimensional theories, string-inspired scenarios, and modified gravity. Using a Markov Chain Monte Carlo framework, we constrain the model with the latest high-precision observational datasets–Cosmic Chronometers, Baryon Acoustic Oscillation, Pantheon<span>(^+)</span>, and DES-SN5YR Type Ia Supernovae. The combined data significantly tighten the parameter bounds on <span>((H_0, Omega _{m_0}, eta _0, gamma ))</span> and yield predictions for the Hubble parameter <i>H</i>(<i>z</i>), the distance modulus <span>(mu (z))</span>, and the scaled comoving angular diameter distance that remain in excellent agreement with observations and closely follow the <span>(Lambda )</span>CDM baseline. In addition, an information-theoretic model comparison based on the Akaike Information Criterion shows that the exponential quintessence model remains statistically comparable with the <span>(Lambda )</span>CDM scenario, despite the penalty associated with its additional parameters. The model naturally reproduces the transition from matter domination to late-time acceleration, maintains total equation of state <span>(omega _{textrm{tot}} &gt; -1)</span> as expected for canonical scalar fields, and provides an age of the universe consistent with <i>Planck</i> 2018. The Statefinder diagnostics show trajectories approaching the <span>(Lambda )</span>CDM fixed point, while allowing small observable departures. Energy condition analysis confirms physical viability, with only the Strong Energy Condition violated at late times, as required for acceleration. Overall, our results show that quintessence with an exponential potential provides a stable, observationally consistent alternative to <span>(Lambda )</span>CDM. Using the latest high-precision datasets, we obtain some of the most stringent constraints on this exponential-potential quintessence model, reaffirming its viability as a compelling dynamical explanation for dark energy.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15672-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Repetitive Penrose process in Kerr-de Sitter black holes","authors":"Ke Wang,&nbsp;Xiao-Xiong Zeng","doi":"10.1140/epjc/s10052-026-15655-7","DOIUrl":"10.1140/epjc/s10052-026-15655-7","url":null,"abstract":"<div><p>Recently, references [1, 2] found that the repetitive Penrose process cannot extract all the extractable rotational energy of a Kerr black hole, and reference [3] found that the repetitive electric Penrose process cannot extract all the electrical energy of a Reissner-Nordström (RN) black hole. In this paper, we intend to study the repetitive Penrose process in the Kerr-de Sitter (Kerr-dS) black hole. We will explore influences of the cosmological parameter on the repetitive Penrose process. The results show that, apart from the comparable features documented earlier, the Kerr-dS black hole yields a higher energy return on investment (EROI) and single-extraction energy capability compared to the Kerr black hole. Specifically, the larger the cosmological parameter, the stronger the EROI and the single-extraction energy capability. Furthermore, we also find that at a lower decay radius, the Kerr black hole exhibits a higher energy utilization efficiency (EUE) and more extracted energy after the repetitive Penrose process is completed. However, at a higher decay radius, the situation is reversed, i.e., the Kerr-dS black hole exhibits a higher EUE and more extracted energy, which is due to the existence of stopping condition of the iteration.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15655-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical experiments with a regular charged black hole","authors":"Felipe Medeiros,&nbsp;H. P. de Oliveira","doi":"10.1140/epjc/s10052-026-15707-y","DOIUrl":"10.1140/epjc/s10052-026-15707-y","url":null,"abstract":"<div><p>In this work, we studied the Ayon-Beato Garcia (ABG) solution describing a nonsingular charged black hole using the moving-puncture method. As the first step, we obtained the BG solution in isotropic coordinates with a new, accurate numerical procedure. By focusing on the situation where there is at least one horizon, where the charge is smaller than or equal to a particular critical value, we show the transition between the wormhole geometry described by the isotropic solution to a time-independent trumpet foliation resulting from the disconnection of the two asymptotic regions of the wormhole geometry. The numerical experiments indicate that, as the charge approaches its critical value, the trumpet geometry approaches the extreme isotropic solution.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15707-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Updated observational constraints on interacting holographic dark energy models in a non-flat universe","authors":"Xiaofang Shen,&nbsp;Bing Xu,&nbsp;Kaituo Zhang,&nbsp;Xiangyun Fu,&nbsp;Qihong Huang,&nbsp;Liangliang Ren,&nbsp;Zelin Zhang","doi":"10.1140/epjc/s10052-026-15637-9","DOIUrl":"10.1140/epjc/s10052-026-15637-9","url":null,"abstract":"<div><p>In this paper, we update constraints on the Holographic Dark Energy (HDE) model and the Interacting Holographic Dark Energy (IHDE) models in a non-flat universe, building upon our previous work in which the flat HDE and IHDE models were tested using same datasets, including DESI DR2 BAO, the five-year supernovae sample from DES, CMB distance priors, observational Hubble parameter data, and the local measurement of Hubble constant. Our results indicate that in the HDE model, an open universe is supported at <span>(6sigma )</span>, whereas in the IHDE models a closed universe is favored at over <span>(3sigma )</span>. The model parameter <i>c</i> is anti-correlated with <span>(H_0)</span> in all these models, implying that a resolution to <span>(H_0)</span> tension by reducing the parameter <i>c</i> comes at the expense of a Big Rip fate. Furthermore, using AIC, BIC, DIC, and Bayes evidence, we find that within the non-flat framework, the <span>(Lambda )</span>CDM model remains the most strongly supported by the data, while the HDE model is the most disfavored. Compared with the HDE model, the IHDE models demonstrate markedly improved agreement with the data, and the most strongly supported IHDE model is the one with the interaction term <span>(Q=3beta H_{textrm{0}}frac{rho _{textrm{dm}}rho _{textrm{de}}}{rho _{textrm{dm}}+rho _{textrm{de}}})</span>.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15637-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-throat asymptotically flat wormholes","authors":"Mauricio Cataldo,&nbsp;Antonella Cid,&nbsp;Pedro Labraña","doi":"10.1140/epjc/s10052-026-15704-1","DOIUrl":"10.1140/epjc/s10052-026-15704-1","url":null,"abstract":"<div><p>We present a systematic construction of traversable wormhole spacetimes featuring two symmetric throats within the framework of General Relativity. Our approach employs the embedding formalism by imposing the analytic relation <span>(r - r_0 = K(z^2 - a)^2)</span> between the radial coordinate and the embedding function, which naturally guarantees the flare-out condition at both throats. This ansatz yields a composite shape function <i>b</i>(<i>r</i>) consisting of two branches: an asymptotically flat branch (<span>(epsilon = +1)</span>) extending to spatial infinity, and an intermediate tunnel branch (<span>(epsilon = -1)</span>) with restricted domain <span>(r_0 le r le r_0 + Ka^2)</span>, connecting the two throats positioned at <span>(z = pm sqrt{a})</span> with separation <span>(2sqrt{a})</span>. Analysis of the Einstein field equations reveals that the supporting matter violates the weak, null, and dominant energy conditions throughout the spacetime, while the strong energy condition is identically satisfied with <span>(rho + p_r + 2p_t = 0)</span>. A critical finding is the direct connection between throat separation and energy density: configurations with <span>(0&lt; a &lt; 1/(16Kr_0))</span> admit positive energy density at the throats with phantom-type radial pressure (<span>(omega _r &lt; -1)</span>) and dark-energy-like effective behavior (<span>(omega _{text {eff}} &lt; 0)</span>), whereas larger separations <span>(a &gt; 1/(16Kr_0))</span> require negative energy density. Notably, configurations with phantom matter at the throats require such small values of <i>a</i> that the intermediate tunnel region becomes almost imperceptible, with the two throats nearly coincident, approaching the limiting case of a single-throat geometry. The geometric structure is visualized through embedding diagrams, which demonstrate that increasing the parameter <i>a</i> produces more pronounced and sharply defined throats. This work establishes that multi-throat wormhole geometries can be systematically generated through embedding techniques, providing a complementary approach to field-theoretic constructions and revealing how topological complexity relates to exotic matter distributions in traversable spacetimes.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15704-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can Hawking effect of multipartite state protect quantum resources in Schwarzschild black hole?","authors":"Shu-Min Wu,&nbsp;Xiao-Wei Teng,&nbsp;Hui-Chen Yang,&nbsp;Rui-Yang Xu,&nbsp;P. H. M. Barros,&nbsp;H. A. S. Costa","doi":"10.1140/epjc/s10052-026-15702-3","DOIUrl":"10.1140/epjc/s10052-026-15702-3","url":null,"abstract":"<div><p>Most previous studies on relativistic quantum information have primarily focused on the vacuum state <span>(|0rangle )</span> and the first excited state <span>(|1rangle )</span> in two-mode entangled systems. In this work, we go beyond these limitations by considering arbitrary <i>q</i>-th excited states <span>(|qrangle )</span>, aiming to investigate their role in preserving quantum resources. We analyze the influence of the Hawking effect on multipartite quantum states in the Schwarzschild spacetime, with particular attention to quantum entanglement and coherence. Our results show that, under the influence of the Hawking effect, increasing the excitation number <i>q</i> leads to a reduction in quantum entanglement and mutual information, while enhancing quantum coherence. This indicates that the Hawking effect on excited multipartite states tends to degrade quantum correlations but simultaneously protects quantum coherence in curved spacetime. Therefore, when implementing quantum information protocols in gravitational settings, reducing the excitation number <i>q</i> is favorable for maintaining entanglement, whereas increasing <i>q</i> may be advantageous for tasks that rely on quantum coherence in relativistic quantum information processing.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15702-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-resonant dark matter with (Z_4) gauged symmetry","authors":"Lucca Radicce Justino,&nbsp;Seong-Sik Kim,&nbsp;Hyun Min Lee,&nbsp;Jun-Ho Song","doi":"10.1140/epjc/s10052-026-15621-3","DOIUrl":"10.1140/epjc/s10052-026-15621-3","url":null,"abstract":"<div><p>We present a new model for two-component scalar dark matter (DM), consisting of two complex scalar fields. In this model, both the DM components are stable due to the remaining <span>(Z_4)</span> gauge symmetry, which is the remnant of the <span>(U(1)^prime )</span> local symmetry. When the resonance condition for DM masses is fulfilled, we show that the elastic co-scattering processes between two components of dark matter (<i>u</i>-channel processes) are enhanced due to the Yukawa potential with a small effective mass for the lighter DM mediator, so we can use such co-scattering processes for dark matter to explain the small-scale problems at galaxies. Moreover, there are also semi-annihilation processes that two components of dark matter annihilate into one dark matter particle and a dark photon/Higgs, which are enhanced by the <i>u</i>-channel Sommerfeld factor. Focusing on some benchmark models for two-component dark matter satisfying the observed relic density, we obtain the bounds for the dark photon portal couplings from the direct detection for boosted dark matter, which is produced from the semi-annihilation processes at the galactic center.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15621-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Type-I seesaw framework with non-holomorphic modular symmetry","authors":"Cheshta,&nbsp; Priya,&nbsp;Suneel Dutt,&nbsp;B. C. Chauhan","doi":"10.1140/epjc/s10052-026-15675-3","DOIUrl":"10.1140/epjc/s10052-026-15675-3","url":null,"abstract":"<div><p>We study neutrino mass generation within the framework of non-holomorphic modular symmetry proposed by Qu and Ding. In this formalism, neutrino masses are generated via the Type-I seesaw mechanism, where the Yukawa couplings depend on non-holomorphic modular forms. The viability of the model is examined through a <span>(chi ^2)</span> analysis using current neutrino oscillation data. The <span>(chi ^2_{min})</span> value is found to be 7.06 for normal hierarchy(NH). All neutrino oscillation parameters are consistent within their <span>(1sigma )</span> allowed ranges, except the atmospheric mixing angle <span>(sin ^2theta _{23},)</span> which is predicted to lie in the second octant. The Dirac CP-violating phase(<span>(delta _{CP})</span>) is constrained to the first and fourth quadrants, indicating relatively weak CP violation. These predictions can be tested in future long-baseline neutrino oscillation experiments. The sum of neutrino masses is compatible with the stringent bound proposed by the DESI experiment. However, the inverted hierarchy(IH) is not viable in this model, as the predicted value of <span>(chi ^2_{min})</span> exceeds 100, and the mixing angles <span>(sin ^2theta _{12})</span> and <span>(sin ^2theta _{23})</span> lie outside the <span>(3 sigma )</span> allowed ranges.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15675-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking interior curvature to observable shadows: a case study of nonsingular black holes","authors":"Ming-Xin Li,&nbsp;Jin Pu,&nbsp;Yi Ling,&nbsp;Guo-Ping Li","doi":"10.1140/epjc/s10052-026-15668-2","DOIUrl":"10.1140/epjc/s10052-026-15668-2","url":null,"abstract":"<div><p>We establish a direct connection between the interior curvature structure of nonsingular black holes (BHs) with a Minkowski core and their observable optical signatures. By classifying these spacetimes into three fundamental types, <b>Type I</b> (Kretschmann scalar <span>(K_{text {max}})</span> increasing with mass <i>M</i>), <b>Type II</b> (mass-independent <span>(K_{text {max}})</span>), and <b>Type III</b> (<span>(K_{text {max}})</span> decreasing with <i>M</i>), we demonstrate how subtle variations in the core geometry imprint distinguishable features on the BH shadow. A detailed analysis of photon dynamics reveals that the parameters <span>(alpha )</span> and <i>n</i>, which control the deviation from Schwarzschild geometry and the radial decay of the regularizing factor, respectively, systematically alter the properties of the photon sphere. These intrinsic geometric differences propagate outward: for fixed parameters, <b>Type III</b> BHs, with the most compact photon sphere, produce the smallest and brightest shadows, whereas <b>Type I</b> BHs yield the largest and dimmest ones. Shadow computations under both static and infalling spherical accretion models confirm that the curvature-based classification directly corresponds to observable differences. Critically, <b>Type III</b> BHs exhibit the strongest sensitivity to parameter variations, making them optimal probes for constraining the underlying spacetime geometry. Our work reveals that even among nonsingular BHs sharing the same asymptotic core, differences in internal curvature are reflected in the shadow morphology, thereby providing a new pathway to test quantum-gravity-inspired models using upcoming high-resolution observations.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 4","pages":""},"PeriodicalIF":4.8,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-15668-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}