物理最新文献

{"title":"Long lived quasinormal modes in the effective quantum gravity","authors":"S. V. Bolokhov","doi":"10.1140/epjc/s10052-025-14883-7","DOIUrl":"10.1140/epjc/s10052-025-14883-7","url":null,"abstract":"<div><p>Two models for Schwarzschild-like black holes with quantum corrections, derived from the Hamiltonian constraints approach to quantum gravity while preserving general covariance, have been developed in Zhang et al. (Phys. Rev. D <b>111</b>, L081504, 2025, arXiv:2407.10168 [gr-qc]). In this work, we study the quasinormal modes of a massive scalar field and demonstrate that the spectrum includes arbitrarily long-lived modes, known as quasi-resonances. Precise calculations using the Leaver method show good agreement with WKB data and time-domain integration within the range where these methods are reliable, specifically for small field masses.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14883-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316480","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":"Non-radial oscillations and gravitational wave radiation of proto-neutron stars","authors":"Yi-Lun Tao,&nbsp;Zi-Yue Zheng,&nbsp;Ting-Ting Sun,&nbsp;Huan Chen,&nbsp;Jin-Biao Wei","doi":"10.1140/epja/s10050-025-01711-5","DOIUrl":"10.1140/epja/s10050-025-01711-5","url":null,"abstract":"<div><p>We study the <i>g</i>-mode non-radial oscillations of proto-neutron stars during the cooling stage. Based on finite-temperature extended Brueckner–Hartree–Fock theory and the relativistic mean-field theory, and combined with appropriate crust equations of state, we construct isentropic equations of state for proto-neutron stars with neutrino trapping. Under the frozen-fluid assumption during oscillations, the difference between the adiabatic and equilibrium sound speeds gives rise to nonzero Brunt–Väisälä frequencies, which enables the existence of <i>g</i>-mode oscillations. We then study the effects of temperature and neutrino trapping on the <i>g</i>-mode frequencies under the Cowling approximation, making comparisons between results with the two EOSs and examining the impact of varying crust equations of state. Our results show that, compared with cold neutron stars, neutrino trapping significantly reduces gravity-mode frequencies in both models, and the relativistic mean-field model systematically yields lower frequencies than the Brueckner–Hartree–Fock model. Neutrino trapping also prolongs gravitational wave damping times and reduces the strain amplitudes, but predictions indicate that the signals remain within the sensitivity of current and future detectors. These findings highlight the potential of gravitational wave observations to probe the interior physics of proto-neutron stars.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 10","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316144","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":"Tunable mechanical, opto-electronic, and thermoelectric properties of ( Sr_2NbXO_6( X = Al, ) In,  and Tl) double perovskites as a sustainable energy application: insights from first-principles calculations","authors":"K. Elasri,&nbsp;A. Boufoud,&nbsp;E. Darkaoui,&nbsp;S. El asri,&nbsp;S. Mouslih,&nbsp;A. Abbassi,&nbsp;S. Taj,&nbsp;A. Fahmi,&nbsp;B. Manaut","doi":"10.1140/epjb/s10051-025-01067-1","DOIUrl":"10.1140/epjb/s10051-025-01067-1","url":null,"abstract":"<p>Using density functional theory (DFT), we investigated the mechanical, optoelectronic, and thermoelectric properties of the double perovskites <span>(Sr_{2}NbXO_{6} (X = Al, In, text {and}~Tl))</span>. Calculations of the formation energy, cohesion energy, tolerance factor (<span>(tau )</span>), as well as the analysis of the Born–Huang approximation stability criteria, confirm the thermodynamic and mechanical stability of these compounds. Electronic properties show that the compounds <span>(Sr_{2}NbInO_{6})</span> and <span>(Sr_{2}NbTlO_{6})</span> have an indirect band gap with values of 3.43 <i>eV</i> and 2.60 <i>eV</i>,  respectively. In contrast, <span>(Sr_{2}NbAlO_{6})</span> has a direct band gap of 3.69 <i>eV</i>. An analysis of the optical properties, including the real and imaginary parts of the dielectric function <span>((varepsilon _1, varepsilon _2))</span>, the absorption coefficient <span>(alpha (omega ))</span>, the refractive index <span>(n(omega ))</span>, the optical conductivity <span>(sigma (omega ))</span>, and the reflectivity <span>(R(omega ))</span>, was also performed. The results reveal significant absorption of incident light in the ultraviolet (UV) region, indicating that these oxides have strong potential for use in UV optical sensors as well as in various other UV-based optoelectronic devices. Furthermore, the <i>BoltzTraP2</i> code reveals promising values for the Seebeck coefficient, electrical and thermal conductivity, power factor, and figure of merit (ZT). These findings suggest that <span>(Sr_2NbXO_6)</span> compounds are suitable candidates for sustainable energy technologies, particularly in thermoelectric and UV sensor devices.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 10","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316152","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":"Dynamics of chemoreceptor activity with time-periodic attractant field","authors":"Ramesh Pramanik,&nbsp;Ramu K. Yadav,&nbsp;Sakuntala Chatterjee","doi":"10.1140/epje/s10189-025-00525-z","DOIUrl":"10.1140/epje/s10189-025-00525-z","url":null,"abstract":"<p>When exposed to a time-periodic chemical signal, an <i>E.coli</i> cell responds by modulating its receptor activity in a similar time-periodic manner. But there is a phase lag between the applied signal and activity response. We study the variation of activity amplitude and phase lag as a function of applied frequency <span>(omega )</span>, using numerical simulations. The amplitude increases with <span>(omega )</span>, reaches a plateau and then decreases again for large <span>(omega )</span>. The phase lag increases monotonically with <span>(omega )</span> and finally saturates to <span>(3 pi /2)</span> when <span>(omega )</span> is large. The activity is no more a single-valued function of the attractant signal, and plotting activity vs attractant concentration over one complete time period generates a loop. We monitor the loop area as a function of <span>(omega )</span> and find two peaks for small and large <span>(omega )</span> and a sharp minimum at intermediate <span>(omega )</span> values. We explain these results from an interplay between the timescales associated with adaptation, activity switching and applied signal variation. In particular, for very large <span>(omega )</span> the quasi-equilibrium approximation for activity dynamics breaks down, which has not been explored in earlier studies. We perform analytical calculation in this limit and find good agreement with our simulation results.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 10-12","pages":""},"PeriodicalIF":2.2,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316478","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":"Observational properties of a Schwarzschild black hole surrounded by a Dehnen-type dark matter halo","authors":"Zhi Li,&nbsp;Jiancheng Yu","doi":"10.1140/epjc/s10052-025-14911-6","DOIUrl":"10.1140/epjc/s10052-025-14911-6","url":null,"abstract":"<div><p>This study investigates the accretion process and observational signatures of thin accretion disks around a Schwarzschild black hole (BH) embedded in a Dehnen-type dark matter (DM) halo. We examine the influence of the density <span>(rho _{s})</span> and radius <span>(r_{s})</span> of the DM halo on key disk properties, including the energy flux, temperature distribution, and emission spectrum. Our results show that all three of these quantities decrease with increasing <span>(rho _{s})</span> or <span>(r_{s}.)</span> Furthermore, by generating and analyzing both direct and secondary images of the accretion disk, we explore how the observational inclination angle and the DM halo parameters <span>(rho _{s})</span> and <span>(r_{s})</span> affect image profiles. Finally, the observed flux distributions are presented for different inclination angles. Our findings indicate that the accretion disk becomes colder and dimmer as the DM halo parameters increase, highlighting the significant role of DM in shaping BH observables.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14911-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316145","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":"Holographic QCD running coupling for heavy quarks in strong magnetic field","authors":"Irina Ya. Aref’eva,&nbsp;Ali Hajilou,&nbsp;Alexander Nikolaev,&nbsp;Pavel Slepov","doi":"10.1140/epjc/s10052-025-14885-5","DOIUrl":"10.1140/epjc/s10052-025-14885-5","url":null,"abstract":"<div><p>We investigate the influence of a magnetic field on the running coupling constant for a heavy-quark model in a bottom-up holographic approach. To achieve this, we employ a magnetized Einstein–Maxwell–Dilaton background that captures the essential features of heavy quark dynamics. Similar to the light-quark model, the running coupling <span>(alpha )</span> for heavy quarks decreases in the presence of a strong external magnetic field at fixed temperature and chemical potential. The key distinction between the light and heavy quark models lies in the locations of their respective phase transitions. However, near the 1st order phase transitions, the behavior of <span>(alpha )</span> is analogous for both cases: <span>(alpha )</span> exhibits jumps that depend on temperature, chemical potential, and magnetic field strength.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14885-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316149","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":"Localization of q-form field on squared curvature gravity domain wall brane coupling with gravity and background scalar","authors":"Xin-Nuo Zhang,&nbsp;Heng Guo,&nbsp;Yong-Tao Lu","doi":"10.1140/epjc/s10052-025-14900-9","DOIUrl":"10.1140/epjc/s10052-025-14900-9","url":null,"abstract":"<div><p>Unlike the duality in four-dimensional spacetime, where the <i>q</i>-form fields corresponds to the scalar fields or the vector fields, in higher dimensional spacetime, they denote new types of particles. In this paper, we investigate the localization of the KK modes of the <i>q</i>-form fields in a five dimensional brane world. We introduce the coupling between the <i>q</i>-form fields and both the gravity and the background scalar field. This consideration enables the localization of the <i>q</i>-form fields on the five-dimensional RS-2 thick brane, leading to the derivation of zero modes, Schrödinger-like equations, and a four-dimensional effective action. We suggest a new function <span>(F(R,varphi ))</span> to stand for the coupling of the <i>q</i>-form field with gravity and background scalar fields. Our analysis highlights the significance of the parameters <span>(text{ C}_2)</span> and <span>(displaystyle t)</span> in the localization processes.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14900-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316148","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":"Macroscopic states in Bose–Einstein condensate dark matter model with axionlike interaction","authors":"Andriy Nazarenko","doi":"10.1140/epjc/s10052-025-14893-5","DOIUrl":"10.1140/epjc/s10052-025-14893-5","url":null,"abstract":"<div><p>The phase diagrams of ultralight dark matter (DM), modeled as a self-gravitating Bose–Einstein condensate with axionlike interaction, are studied. We classify stable, metastable, and unstable DM states over a wide range of condensate wave function amplitudes. It is shown that the axionlike interaction causes instability and an imaginary speed of sound at low amplitudes, whereas, in a specific high-amplitude band, DM attains a stable state capable of forming a dense solitonic core and suppressing quantum fluctuations in the surrounding galactic DM halo. These findings are corroborated by evaluating thermodynamic functions for DM in the dwarf galaxy NGC 2366 and its hypothetical analogs with different core-to-halo mass ratios. Distinct DM phase compositions respond differently to fluctuation-induced partial pressure, resulting in a first-order phase transition in a certain range of an interaction parameter. While the DM properties in NGC 2366 lie within the supercritical regime, the phase transition nonetheless provides a thermodynamic marker separating stable from unstable DM configurations. Once a dense core forms – reaching a threshold of about 12% of the total mass – the enhanced gravitation stabilizes the DM halo against fluctuations, while the internal pressure ensures core stability. In particular, we find that NGC 2366’s dense DM comprises roughly 19% of the DM mass while occupying only 4.7% of its total volume.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14893-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316146","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":"Lyapunov exponents, phase transitions, and Chaos bound of ModMax AdS black holes","authors":"Gorima Bezboruah,&nbsp;Mozib Bin Awal,&nbsp;Prabwal Phukon","doi":"10.1140/epjc/s10052-025-14920-5","DOIUrl":"10.1140/epjc/s10052-025-14920-5","url":null,"abstract":"<div><p>We study the thermodynamic phase transition of ModMax anti-de Sitter (AdS) black holes using Lyapunov exponents of massless and massive particles in unstable circular orbits. Our results demonstrate that the thermal profile of the Lyapunov exponent serves as an efficient probe of the black hole’s phase structure. We calculate the discontinuity in the Lyapunov exponent across the transition and show that it acts as an order parameter, exhibiting a critical exponent <span>(delta =1/2)</span> in the vicinity of the critical point. Furthermore, we explore the violation of the chaos bound, finding that the bound is violated when the horizon radius falls below a threshold value. We also examine how the ModMax parameter and the particle’s angular momentum modify this threshold, revealing their role in controlling the onset of chaos bound violation.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 10","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14920-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316147","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":"Overview of national regulatory approaches to assess worker’s exposure to radon in industries involving norm","authors":"R. Trevisi,&nbsp;T. Bituh,&nbsp;A. Canoba,&nbsp;M. Chege,&nbsp;A. Cordelle,&nbsp;D. Chambers,&nbsp;N. Chambers,&nbsp;P. Egidi,&nbsp;R. Gellermann,&nbsp;F. Grandia,&nbsp;J. Hondros,&nbsp;C. Kunze,&nbsp;J. Lee,&nbsp;B. Michalik,&nbsp;F. Otoo,&nbsp;S. Pepin,&nbsp;K. N. Rovenska,&nbsp;R. Sapoi,&nbsp;P. Tchokossa,&nbsp;O. van Dongen","doi":"10.1140/epjp/s13360-025-06837-5","DOIUrl":"10.1140/epjp/s13360-025-06837-5","url":null,"abstract":"<div><p>National regulations address the radiological protection of industrial processes involving Naturally Occurring Radioactive Material (NORM), each with different approach. A collection of information gathered by members of the International Radiation Protection Association task group on “NORM” helps identify key differences in regulatory strategies. The main findings indicate that, while national regulations generally implement the requirements of international standards—and, for EU Member States, the provisions of European Commission directives—and consider ICRP recommendations, the regulatory approaches and protocols for managing worker exposure to radon in workplaces involving NORM vary significantly. In most countries, industrial processes involving NORM are regulated as planned exposure situations, whereas exposure to radon in workplaces is typically managed as an existing exposure situation. When radon doses need to be assessed because requirements for planned exposure situations apply, national regulations often require that these contributions be recorded and treated separately. However, in several countries, the contribution from radon inhalation is explicitly incorporated into the total effective dose assessment. In certain cases, the calculation specifically accounts only for the radon exposure attributable to the handling of NORM, excluding background or unrelated sources. The methodology for estimating radon doses can vary significantly between countries. There is a lack of harmonisation in the physical quantities used for assessment, as well as in the values of dose conversion factors.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316583","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}