物理最新文献

{"title":"Stochastic transitions between neutral and bimodal affective states under contradictory stimulation","authors":"Renato Vieira dos Santos","doi":"10.1140/epjb/s10051-026-01275-3","DOIUrl":"10.1140/epjb/s10051-026-01275-3","url":null,"abstract":"<p>A person opens their news feed and finds, in rapid succession, a story that inspires hope and another that provokes outrage. This alternation between contradictory emotional valences is the ordinary texture of contemporary media environments. What are the long-term consequences of such <i>contradictory stimulation</i> on an individual’s core affective state—the continuous background feeling of being comfortable or uncomfortable, well or unwell, that colours all emotional experience? Could the long-term consequences depend less on the content of any single message than on the statistical structure of the stream’s inconsistency? We capture this structure in a minimal stochastic model that treats the strength of external influence as a fluctuating parameter, yielding a stochastic differential equation with multiplicative noise. Its stationary distribution reveals two regimes that defy straightforward intuition. Intense contradiction does not amplify engagement but instead drives the affective state toward neutrality—a form of apathy in which sustained affect is suppressed altogether; exact neutrality occurs only when the default bias vanishes. Conversely, moderate contradiction with strong influence produces bimodal affective instability, with random alternation between two well-separated emotional states that arise from intra-individual dynamics rather than social polarization. A systematic mapping of the parameter space reveals a region of robust bimodality for low regulatory capacity and a region of enhanced fragility for near-neutral default bias. We offer this model as a preliminary exploration rather than a definitive account, and we hope its analytical transparency will invite empirical testing and further theoretical development.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"99 10","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjb/s10051-026-01275-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132641","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":"Visible‐light excitable TiO2/Na-P-g-C3N4 heterojunction catalysts for photocatalytic epoxidation of styrene","authors":"Jiacheng Xu,&nbsp;Yumeng Qiao,&nbsp;Tongqin Zhang,&nbsp;Rong Hou,&nbsp;Li Huang,&nbsp;Haiyong Liu,&nbsp;Fuyou Wang,&nbsp;Hui Xie","doi":"10.1007/s00339-026-10298-7","DOIUrl":"10.1007/s00339-026-10298-7","url":null,"abstract":"<div><p>A composite photocatalyst consisting of titanium-deposited sodium and phosphorus co-modified graphitic carbon nitride (TiO₂/Na-P-g-C₃N₄) was successfully synthesized via calcination and hydrothermal methods. The prepared photocatalyst was characterized using XRD, FT-IR, BET, SEM, TEM, EDX, XPS, UV–vis DRS, PL, Mott-Schottky and EIS to elucidate its structural and photoelectrochemical properties. Subsequently, the conditions for the photocatalytic epoxidation of styrene were optimized. The results demonstrated the successful construction of a heterostructure between TiO₂ and Na-P-g-C₃N₄, with the 20% TiO₂/Na-P-g-C₃N₄ sample exhibiting an outstanding specific surface area, the lowest band gap energy, the weakest photoluminescence intensity, and the minimal interfacial charge transfer resistance. Owing to its superior photoelectrochemical properties, the 20% TiO₂/Na-P-g-C₃N₄ catalyst achieved a high styrene conversion rate of 58.67% and a styrene oxide selectivity of 83.75% under conditions employing 30 wt% hydrogen peroxide aqueous solution as the oxidant and acetonitrile as the solvent. The catalytic activity of this composite was found to be five times greater than that of pure g-C₃N₄. Furthermore, combined analysis of the band structure, XPS binding-energy shifts, and radical scavenging experiments suggests that the TiO₂/Na-P-g-C₃N₄ photocatalyst operates via a Z-scheme heterojunction charge-transfer mechanism.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"132 11","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, optical, electrochemical and photocatalytic properties of Ni-doped ZnO nanoparticles","authors":"A. Suvitha,&nbsp;R. Arunkumar,&nbsp;L. Bruno Chandrasekar,&nbsp;P. Shunmuga Sundaram","doi":"10.1140/epjb/s10051-026-01271-7","DOIUrl":"10.1140/epjb/s10051-026-01271-7","url":null,"abstract":"<div><p>Nickel-doped zinc oxide nanoparticles are successfully synthesized using the chemical precipitation method. Structural, optical, electrochemical, and photocatalytic properties of the prepared nanoparticles are investigated. X-ray diffraction analysis confirms the hexagonal Wurtzite structure. The crystallite size is found to decrease from 34 to 20 nm with increasing nickel content. The increased dislocation density and micro-strain indicate enhance lattice distortion. Lattice parameters and bond length exhibit slight variations without secondary phase formation. Energy-dispersive X-ray spectroscopy mapping confirms the uniform distribution of the elements. UV–Vis reflectance spectra show a shift in the absorption edge. The range of band gap of the prepared material is 3.20–3.25 eV. The prepared material is used as an electrode material in the supercapacitors and the corresponding specific capacitance is calculated. The degradation of the organic pollutant with the prepared nanoparticles as a catalyst is reported. The degradation efficiency and kinetic rate constants are examined. The pseudo-first-order rate constant for methylene blue increases from 0.0105 to 0.01964/min, while for Rhodamine B, it increases from 0.00955 to 0.01483/min as the nickel doping concentration is increased from 0 to 6%.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"99 10","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132526","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":"Influence of Sm³⁺ substitution on the structural, magnetic, and dielectric properties of SrFe12O19 hexaferrites","authors":"V. Prasad,&nbsp;A. Raghavendra Rao,&nbsp;K. Anil Kumar,&nbsp;V. Srinivasa Rao,&nbsp;T. Madhu Mohan","doi":"10.1007/s00339-026-10322-w","DOIUrl":"10.1007/s00339-026-10322-w","url":null,"abstract":"<div><p>The sol-gel auto-combustion method has been used to prepared M-type Sr_1−xSm_xFe₁₂O₁₉ hexagonal ferrite nanoparticles with various compositions x = 0.0, 0.02, 0.04, 0.06, 0.08 and 0.1 respectively. The samples were sintered for 4 h at 1200 °C for the reaction to occur and investigate the effects of Sm³⁺ substitution on the host material’s structural, magnetic, and dielectric properties. The properties of these were investigated using XRD, FESEM, FTIR, magnetic, and impedance analysis. The confirmation of the formation of the crystalline M-type has been carried out by XRD patterns, which were identified as pure hexagonal with space group P6₃<i>/mmc</i> (No. 194). The morphology observed under FESEM was a speckle-like morphology in the nanoscale. FTIR analysis confirmed the synthesis of hexaferrite, where stretching bands of oxygen atoms and metal ions (M–O), in this case the Fe–O bond is observed in the range 413–421 cm^− 1 and 586–593 cm^− 1. The saturation magnetization decreases with increasing concentrations and is low at x = 0.10. The concentration of Sm³⁺ increases the coercivity. The dielectric analysis showed that the sample has a frequency-dependent behavior, with the highest dielectric constant value of the synthesized sample and a low value for dielectric loss. The polarization and conduction mechanisms were explained by Koop’s theory, the Maxwell-Wagner model, and the Verwey hopping model.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"132 11","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reaction-field-regulated Fe₂O₃/carbon-paper cathodes for reliable lithium–oxygen energy-storage materials","authors":"Suleiman Ibrahim Mohammad,&nbsp;Asokan Vasudevan,&nbsp;Rashed Abu Hammour,&nbsp;Rekha M. M.,&nbsp;Abhilasha Mishra,&nbsp;Rahul Saxena,&nbsp;Lalita Chopra,&nbsp;Faiz Mahmood,&nbsp;Nosir Xurramov,&nbsp;Amirali Nikpendar","doi":"10.1007/s00339-026-10292-z","DOIUrl":"10.1007/s00339-026-10292-z","url":null,"abstract":"<div><p>Emerging energy-storage materials require electrode architectures that not only enhance electrochemical activity but also regulate transport, reaction distribution, discharge-product accumulation, and structural reliability. Lithium–oxygen batteries are attractive high-energy-density systems; however, their practical performance is strongly limited by oxygen depletion, heterogeneous Li₂O₂ deposition, pore blockage, film-resistance growth, charge polarization, and mechanically induced degradation within porous cathodes. Herein, ultralow Fe₂O₃ loading (~ 1 wt%) on P50 carbon-paper cathodes is investigated as a reaction-field-regulating material strategy for improving Li–O₂ cathode operation. A coupled physicochemical framework was developed to resolve oxygen transport, lithium-ion migration, electronic and ionic charge conservation, Butler–Volmer interfacial kinetics, Li₂O₂ deposition/decomposition, porosity evolution, film-resistance growth, and Li₂O₂-induced stress formation. Compared with pristine P50, the Fe₂O₃/P50 cathode increased final oxygen availability by 26.8% and improved the Reaction Uniformity Index by 28.6%, demonstrating that dispersed Fe₂O₃ domains redistribute electrochemical activity across the porous carbon-paper network. This redistribution reduced mean Li₂O₂ thickness by 24.1%, improved porosity retention by 13.0%, decreased film resistance by 31.7%, and lowered charge overpotential by 7.4%. Mechanically, Fe₂O₃/P50 reduced maximum Von Mises stress by 33.4%, high-risk stressed area by 46.5%, and the Mechanical Reliability Index by 41.1%. The predicted 7.4% reduction in charge overpotential was quantitatively consistent with the experimentally reported ~ 7.0% reduction for Fe₂O₃/P50 cathodes, corresponding to a normalized RMSE of 0.0028. Additional qualitative agreement was obtained with reported XRD evidence of reversible Li₂O₂ formation/decomposition and SEM observations of less localized Li₂O₂ deposition. These results indicate that ultralow Fe₂O₃ loading acts beyond conventional catalytic acceleration, functioning as a materials-level regulator of reaction uniformity, transport preservation, Li₂O₂ distribution, and mechanical reliability. The study provides a design principle for developing reliable metal-oxide-modified carbon cathodes for next-generation Li–O₂ energy-storage materials.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"132 11","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoexcitation of low-energy transitions in (^{229})Th by a Laguerre–Gaussian beam","authors":"N. A. Ashurko,&nbsp;O. V. Bogdanov,&nbsp;Y. Wang","doi":"10.1140/epjd/s10053-026-01259-z","DOIUrl":"10.1140/epjd/s10053-026-01259-z","url":null,"abstract":"<p>The photoexcitation of low-energy nuclear transitions by twisted photons carrying orbital angular momentum and described by Laguerre–Gaussian modes has been theoretically investigated. An analytical expression for the absorption probability is derived that explicitly incorporates <span>(sigma _perp )</span> and <span>(sigma _3)</span> are the half-widths of the photon momentum distributions in the transverse <span>(k_perp )</span> and longitudinal <span>(k_3)</span> directions in momentum space, as well as the radial index <span>(n_gamma )</span> and the helicity <span>(lambda )</span> of the beam. Numerical calculations are performed for the unique isomeric transition in the <span>(^{229}textrm{Th})</span> nucleus with an energy of 8.338 eV, which represents a mixture of M1 and E2 multipolarities. The ratio of the E2 channel excitation probabilities for LG and Bessel beams, as well as the conditions under which the LG mode becomes more efficient, is analyzed.</p><p>\"The configuration of the Laguerre -Gaussian beam with respect to the atomic nucleus <span>(^{229})</span>Th\"</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132825","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":"Hybrid scheme of positron photoproduction for Siberian Ring Photon Source facility","authors":"S. V. Abdrashitov,&nbsp;O. V. Bogdanov,&nbsp;S. V. Bragin","doi":"10.1140/epjd/s10053-026-01263-3","DOIUrl":"10.1140/epjd/s10053-026-01263-3","url":null,"abstract":"<p>Numerical simulation of a positron source for the SKIF accelerator complex (Siberian Ring Photon Source) has been performed. The scheme employs a primary 200 MeV electron beam to generate photons in a crystalline target (radiator), followed by electron-positron pair production in an amorphous target (converter) — a configuration known as the hybrid positron source scheme. A diamond crystal is considered as the radiator for the generation of coherent bremsstrahlung. Amorphous tungsten W is chosen as the converter. Energy spectra of positrons produced in a thin converter are obtained. Positron energy losses and radiation attenuation within the converter bulk are taken into account in order to determine the optimal converter thicknesses providing the maximum total positron yield when using a diamond radiator for coherent bremsstrahlung. Energy spectra of positrons at the optimal converter thickness are calculated. A comparison with incoherent bremsstrahlung is carried out.</p><p>The caption for the graphical abstract is: Hybrid scheme of a positron source</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132527","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":"Consistency conditions and the derivation of harmonic structure in Einstein-Maxwell-dilaton theory","authors":"Bardia H. Fahim,&nbsp;Joshua G. Fenwick","doi":"10.1140/epjc/s10052-026-16426-0","DOIUrl":"10.1140/epjc/s10052-026-16426-0","url":null,"abstract":"<div><p>Many exact solutions of Einstein–Maxwell and Einstein–Maxwell-dilaton theory share a common structural pattern in which the metric functions are built from harmonic functions on a specified spatial base, often taken to be flat. We investigate this pattern by considering the Einstein–Maxwell-dilaton theory in arbitrary dimensions, where the dilaton field is non-trivially coupled to the Maxwell field and to a Liouville-type potential proportional to the cosmological parameter. Without imposing either the base geometry or the harmonic form of the metric function in advance, we show that for the generic branch, the field equations force the dilaton couplings to be equal, restrict the spatial base geometry to be Ricci flat, and make the metric function harmonic on this base. The resulting spacetime can then be written in terms of a conformal potential. We also consider a purely spatial branch, which instead leads to a distinct constraint on the coupling constants. These results provide a unified field-equation derivation of the harmonic behavior and conformal structure that appear in several classes of solutions, including multi-center geometries, cosmological solutions, and dynamical black holes.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 10","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16426-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133063","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":"High-reflectance modulation and refractive index sensing of all-dielectric composite nanogratings in the visible spectrum","authors":"Tongkai Gu,&nbsp;Zekun Zhang,&nbsp;Anjiang Cai","doi":"10.1140/epjp/s13360-026-08393-y","DOIUrl":"10.1140/epjp/s13360-026-08393-y","url":null,"abstract":"<div><p>This study proposes an all-dielectric composite nanograting structure comprising a TiO₂ subwavelength grating and a SiO₂/TiO₂ multilayer dielectric film, designed to achieve high-reflectance modulation and refractive index (RI) sensing in the visible spectrum. A theoretical model was established based on the effective medium theory (EMT) and the transfer matrix method (TMM). Furthermore, the finite-difference time-domain (FDTD) method was employed to systematically analyze the effects of the number of multilayer periods, duty cycle, and grating height on the reflection spectra. The results indicate that the bottom multilayer film significantly enhances the optical feedback. Specifically, when the number of periods reaches <i>N</i> = 5, the structure achieves a maximum reflectance of over 99%. Variations in the duty cycle and grating height can effectively tune the resonance wavelength while maintaining a stable Fano resonance lineshape. The proposed structure achieves a RI sensitivity of 465.97 nm/RIU within the ambient RI range of <i>n</i>_c = 1.33–1.37, alongside a quality factor of 153.3, demonstrating a highly linear response and excellent application potential.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132693","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":"Fire at the tip of the throat: Hagedorn phase after brane–antibrane inflation?","authors":"Dibya Chakraborty,&nbsp;Ahmed Rakin Kamal","doi":"10.1140/epjc/s10052-026-16470-w","DOIUrl":"10.1140/epjc/s10052-026-16470-w","url":null,"abstract":"<div><p>We study the post-inflationary open-string Hagedorn phase in perturbatively moduli stabilized brane– antibrane inflation. In this class of models, the volume modulus is stabilized by perturbative corrections rather than by non-perturbative effects to the superpotential, thereby avoiding the standard brane–antibrane <span>(eta )</span>-problem. Since inflation ends through tachyon condensation and brane–antibrane annihilation, the endpoint is intrinsically stringy and need not be described immediately by an ordinary radiation bath. We analyze whether the energy released at annihilation can drive the visible sector into an open-string Hagedorn phase, and study the consequences for dark radiation. If the Standard Model (SM) branes lie in the same throat as where the annihilation occurs, we find that a modest fraction of the released energy deposited into surviving visible open strings is sufficient to enter the Hagedorn regime and can suppress the effective number of relativistic species <span>(Delta N_textrm{eff})</span> below current observational bounds. If the SM lies in a different throat, the result depends on inter-throat energy transfer: prompt or delayed transfer can still yield a visible Hagedorn phase. However, the mechanism is most efficient when the local string scale in the SM throat is lower than or comparable to that in the annihilation throat.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"86 10","pages":""},"PeriodicalIF":4.9,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-026-16470-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132832","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}