物理最新文献

{"title":"Black holes in (f(R)) gravity coupled to nonlinear electromagnetic fields","authors":"Yong-Ben Shi,&nbsp;Rong-Jia Yang","doi":"10.1140/epjp/s13360-025-06361-6","DOIUrl":"10.1140/epjp/s13360-025-06361-6","url":null,"abstract":"<div><p>We establish a framework to construct spherically symmetric and static solutions in <span>(f(R))</span> gravity coupled with nonlinear electromagnetic fields. We present two new specific solutions and discuss the energy conditions. We calculate some thermodynamic quantities of the obtained black holes like entropy and energy and investigate their thermodynamic topology.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"A meta-analysis of impact factors of astrophysics journals","authors":"Rayani Venkat Sai Rithvik,&nbsp;Shantanu Desai","doi":"10.1140/epjp/s13360-025-06397-8","DOIUrl":"10.1140/epjp/s13360-025-06397-8","url":null,"abstract":"<div><p>We calculate the 2024 impact factors for the 38 most widely used journals in Astrophysics, using the citations collated by NASA/Astrophysics Data System (ADS), and compare them to the official impact factors. This includes journals which publish papers outside of astrophysics such as PRD, EPJC, and Nature. We also propose a new metric to gauge the impact factor based on the median number of citations in a journal and calculate the same for all the journals. We find that the ADS-based impact factors are mostly in agreement, albeit higher than the official impact factors for most journals. The journals with the maximum fractional difference in median-based and old impact factors are JHEAP and PTEP. We find the maximum difference between the ADS and official impact factor for Nature.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Fully heavy asymmetric scalar tetraquarks","authors":"S. S. Agaev,&nbsp;K. Azizi,&nbsp;H. Sundu","doi":"10.1140/epja/s10050-025-01599-1","DOIUrl":"10.1140/epja/s10050-025-01599-1","url":null,"abstract":"<div><p>The scalar tetraquarks <span>(T_{b})</span> and <span>(T_{c})</span> with asymmetric contents <span>(bb overline{b}overline{c})</span> and <span>(cc overline{c}overline{b})</span> are explored using the QCD sum rule method. These states are modeled as the diquark–antidiquarks composed of the axial-vector components. The masses and current couplings of <span>(T_{b})</span> and <span>(T_{c})</span> are calculated using the two-point sum rule approach. The predictions obtained for the masses of these four-quark mesons prove that they are unstable against the strong two-meson fall-apart decays to conventional mesons. In the case of the tetraquark <span>( T_{b})</span> this is the decay <span>(T_{textrm{b}}rightarrow eta _{b}B_{c}^{-})</span>. The processes <span>(T_{textrm{c}}rightarrow eta _{c}B_{c}^{+})</span> and <span>(J/psi B_{c}^{*+})</span> are kinematically allowed decay modes of the tetraquark <span>( T_{c})</span>. The widths of corresponding processes are evaluated by employing the QCD three-point sum rule approach which are necessary to estimate strong couplings at the tetraquark-meson-meson vertices of interest. The mass <span>( m=(15698 pm 95)~textrm{MeV})</span> and width <span>(Gamma [T_b]=(36.0 pm 10.4)~ textrm{MeV})</span> of the tetraquark <span>(T_{b})</span> as well as the parameters <span>( widetilde{m}=(9680 pm 102)~textrm{MeV})</span> and <span>(Gamma [T_c]=(54.7 pm 12.6)~ textrm{MeV})</span> in the case of <span>(T_{c})</span> provide useful information to search for and interpret new exotic states.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Nonlinear wave investigation for the generalized variable-coefficient Calogero–Bogoyavlenskii–Schiff system","authors":"Yuxin Song,&nbsp;Guangmei Wei,&nbsp;Tianwei Qiu","doi":"10.1140/epjp/s13360-025-06347-4","DOIUrl":"10.1140/epjp/s13360-025-06347-4","url":null,"abstract":"<div><p>This paper extends the classical Calogero–Bogoyavlenskii–Schiff system into a more generalized model by introducing two additional linear terms and incorporating time-dependent coefficients. The bilinear form is given out by the Hirota bilinear method, and abundant analytic solutions are obtained, including the soliton, lump, and breather solutions. Furthermore, the propagation characteristics of these solutions and the interaction between lump soliton and one stripe soliton are discussed.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Screen chaotic motion by Shannon entropy in curved spacetimes","authors":"Wenfu Cao,&nbsp;Yang Huang,&nbsp;Hongsheng Zhang","doi":"10.1140/epjc/s10052-025-14310-x","DOIUrl":"10.1140/epjc/s10052-025-14310-x","url":null,"abstract":"<div><p>We find a novel characteristic for chaotic motion by introducing Shannon entropy for periodic orbits, quasiperiodic orbits, and chaotic orbits. We compare our approach with the previous methods including Poincaré section, Lyapunov exponent, fast Lyapunov indicator, recurrence plots (Rps), and fast Fourier transform (FFT) for orbits around black holes immersed in magnetic fields, and show that they agree with each other quite well. The approach of Shannon entropy is intuitively clear, and theoretically reasonable since it becomes larger and larger from a periodic orbit to chaotic orbit. We demonstrate that Shannon entropy can be a powerful probe to distinguish between chaotic and regular orbits in different spacetimes, and reversely may lead to a new route to define the entropy for a single orbit in phase space, and to find more fundamental relations between thermodynamics and dynamics. Furthermore, we find that the fluctuations of entropy of chaotic orbits are stronger than those of order orbits.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14310-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125811","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":"Installation of an integrated air quality and meteorological parameters monitoring system in Ondo, Nigeria","authors":"Oluwajenrola Akintomide,&nbsp;Christopher J. Olowookere,&nbsp;Idowu Makinde,&nbsp;Oluwaseun S. Oke,&nbsp;Shina A. Solomon,&nbsp;Olumuyiwa James Peter","doi":"10.1140/epjp/s13360-025-06375-0","DOIUrl":"10.1140/epjp/s13360-025-06375-0","url":null,"abstract":"<div><p>Air pollution poses a threat to humans and the natural environment. Unfortunately, the high-tech equipment required to quantify and quickly mitigate the air pollution effect remains scarce in many research locations in the low- and middle-income countries (LMICs). The study constructed a rigid support framework, assembled device components, and installed an integrated air quality and meteorological parameters monitoring station (IAQ-MPMS) at the University of Medical Sciences, Ondo City. Before we conducted this study, the research equipment did not exist in Ondo State. The IAQ-MPMS is subdivided into a hardware subsystem (AirVisual monitor, solar panel, power bank, and other accessories) and a software subsystem (codes, cloud storage, and the smartphone application). The AirVisual monitor unit was powered by the abundant solar energy in Nigeria (using a PV module and other solar hardware). The equipment was deployed to the field, configured, and tested to work well. After the calibration and validation, the real-time data extracted from the study location by the IAQ-MPMS was displayed online to the general public free of charge using software programmes. Its analytic platform uses codes to make a seven-day prediction with precision on air quality, meteorological parameters, and weather conditions. Furthermore, the data generated by the station in 2024 was downloaded from the cloud and analysed using Python tools. The results showed seasonal variation in the air quality parameters in Ondo. The air quality was moderate (AQI at 68–65) in the rainy season (August, September, and October); it was unhealthy to sensitive people (AQI at 121) in November and peaked at unhealthy (AQI at 169) to the public health outdoors in December. The air quality exceeded the WHO’s recommended limits. It can be attributed to local emissions, meteorological parameters, and air mass impact from the Atlantic Ocean or the Saharan Desert in the northern part of the country. Also, seasonal variation occurred in the meteorological parameters in Ondo. For instance, the temperature values were higher (28.8–28.6 °C) in the dry season than in the rainy season (temperature values of 24.0 °C, 25.1 °C, and 26.0 °C). The obtained data was consistent with the existing literature in Southern Nigeria. The government and stakeholders are encouraged to develop effective strategies to mitigate the observed air pollution level.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Effect of tensile strain on the optoelectronic properties of defective Te systems MoTe2","authors":"Zhihong Shi,&nbsp;Ying Wang,&nbsp;Nan Yang,&nbsp;Jinghan Ji,&nbsp;Guili Liu,&nbsp;Guoying Zhang","doi":"10.1140/epjb/s10051-025-00948-9","DOIUrl":"10.1140/epjb/s10051-025-00948-9","url":null,"abstract":"<div><p>In this paper, the modulation of the optoelectronic properties of MoTe₂ defective systems by deformation is simulated using first principles. The study documents the bond lengths, defect formation energies, energy band structures, DOS, and various optical properties of the individual systems in both defect states. It is shown that pristine MoTe₂ is a direct band-gap semiconductor material and that both biaxial tensile strain and defect measures reduce the bandgap of the system. When 2 Te atoms are defective, and the tensile strain reaches 6%, the bandgap of the system approaches 0, corresponding to quasi-metallic properties. In terms of optical properties, both biaxial tensile strain and defects reduce the absorption and reflection peaks of the system but increase the reflectivity in the infrared region. Regarding optical properties, the defective system shows an overall decrease in absorption coefficient and reflectance in the tensile strain state, but there is some increase in the low-energy region. These findings may positively impact the flexible application of MoTe₂ in photovoltaics.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 5","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125702","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}

{"title":"Analysis of regular black hole with multi-polytropic equation of state under various backgrounds","authors":"Farzan Mushtaq,&nbsp;Xia Tiecheng,&nbsp;Allah Ditta,&nbsp;Badr S. Alkahtani","doi":"10.1140/epjp/s13360-025-06349-2","DOIUrl":"10.1140/epjp/s13360-025-06349-2","url":null,"abstract":"<div><p>The purpose of this work is to examine the weak deflection angle, shadow, Regge–Wheeler potential, and greybody factor of a black hole with a multi-polytropic equation of state. In the weak field limit, we use the Gauss–Bonnet theorem along with the Gibbons and Werner method to find the photon’s ray’s deflection angle. Furthermore, we demonstrate how plasma and non-plasma mediums behave with respect to the deflection of photons. Similarly, we examine the graphical effects of the deflection angle on a black hole with a multi-polytropic equation of state, by considering both plasma and non-plasma medium. We also investigate the shadow of a black hole using a multi-polytropic equation of state. Furthermore, we improve our interest by including the spin-dependent Regge–Wheeler potential, which determines the dynamics of perturbations in the presence of the polytropic equation of state black hole. Our analysis of the Regge–Wheeler potential for different spin fields reveals the impact of parameters on its form when monopoles are present. Our study also focused on the rigorous bounds of the black hole with respect to the greybody factor, as well as its graphical behaviour.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Electron capture and ionisation in intermediate-energy C(^{6+}-)He collisions: Integrated cross sections","authors":"K. Schrick,&nbsp;K. H. Spicer,&nbsp;N. W. Antonio,&nbsp;Sh. U. Alladustov,&nbsp;A. S. Kadyrov","doi":"10.1140/epjd/s10053-025-01008-8","DOIUrl":"10.1140/epjd/s10053-025-01008-8","url":null,"abstract":"<div><p>Integrated cross sections for total and state-selective electron capture, and ionisation in C<span>(^{6+}-)</span>He collisions are calculated using the two-centre four-body wave-packet convergent close-coupling method for projectile energies ranging from 2 keV/u to 3 MeV/u. The two-electron target structure accounts for electron-electron correlation effects, as well as electron exchange in the rearrangement C<span>(^{5+}-)</span>He<span>(^{+})</span> channels, which become important at low and intermediate energies. Also used for comparison is an alternative approach that reduces the He target to an effective one-electron system. For electron capture, both methods display good agreement with experiments at high impact energies. For low impact energies the two-electron method performs well, however, the effective single-electron model overestimates available experimental data. Generally good agreement with experiment is found for ionisation cross sections for projectile energies greater than 100 keV/u with both methods. The effective single-electron method is extended down to 10 keV/u, however it overestimates low-energy experiments. It is concluded that the two-electron target description is necessary to correctly model electron capture in the entire range of incident collision energies considered in this work.</p></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 5","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-01008-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144131673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Circular orbits and chaos bound in slow-rotating curved acoustic black holes","authors":"Balbeer Singh,&nbsp;Nibedita Padhi,&nbsp;Rashmi R. Nayak","doi":"10.1140/epjc/s10052-025-14311-w","DOIUrl":"10.1140/epjc/s10052-025-14311-w","url":null,"abstract":"<div><p>Acoustic black holes, analogs of gravitational black holes created in fluid systems, have recently been embedded within Schwarzschild spacetime using the Gross–Pitaevskii theory, leading to configurations with both event and acoustic horizons. This study examines the motion of vortices, modeled as unit-mass relativistic test particles, around a slow-rotating curved acoustic black hole. We analyse the stability of circular orbits, identifying the innermost stable circular orbit (ISCO), and investigate the chaotic dynamics of vortices perturbed from unstable circular orbits near the acoustic horizon. Using the Lyapunov exponent to quantify this chaos, we assess whether it satisfies the Maldacena–Shenker–Stanford bound <span>((lambda le 2 pi T_H))</span>, a limit established for gravitational black holes in general relativity. Our results show that, in non-extremal cases <span>((xi &gt; 4))</span>, the Lyapunov exponent respects the bound near the horizon, while in extremal cases <span>((xi = 4))</span>, it is violated due to vanishing surface gravity. These findings highlight similarities between acoustic and gravitational black holes, advancing the analogy in the context of chaos and orbital dynamics.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14311-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125810","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}