The European Physical Journal Plus最新文献

{"title":"Limitations of the analytical photon skyshine equation: experimental evidence from a fusion facility","authors":"Marco D’Arienzo,&nbsp;Manuela Battistella,&nbsp;Marco Boldrin,&nbsp;Gian Marco Contessa,&nbsp;Samuele Dal Bello,&nbsp;Luca Grando,&nbsp;Silvia Munari,&nbsp;Sergio Biancotto","doi":"10.1140/epjp/s13360-026-07686-6","DOIUrl":"10.1140/epjp/s13360-026-07686-6","url":null,"abstract":"<div><p>Radiation scattered by the air above a radiation facility’s roof and reaching the outdoor ground level is known as skyshine. A commonly employed analytical formula for predicting photon skyshine has been shown to yield significant inaccuracies when compared with a wide range of experimental measurements, with documented discrepancies reaching up to an order of magnitude. Moreover, the model fails to account for the observed dependence on field size and does not reproduce the characteristic local maximum exhibited by skyshine dose rates as a function of distance. This study aims to compare gamma skyshine measurements conducted at a fusion facility with analytical calculations, with the objective of contributing additional data and insights to the existing literature on the subject. Two key findings emerged from the current investigation: (i) When assessing the skyshine dose contribution, it is important to use with extreme caution the basic analytical approaches, particularly when extrapolated to short or long distances or employed in the context of complex shielding geometries. Such methods should be used to get at best an order of magnitude estimate of the skyshine effect. (ii) Contrary to analytical algorithms, the measured photon data show an increase with distance away from the barrier until a maximum is reached at a distance roughly equal to the barrier’s height; beyond this, there is then a steady falloff with distance.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829289","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":"Fundamental physics in 2025: status, decisive targets, and path forward","authors":"Slava G. Turyshev","doi":"10.1140/epjp/s13360-026-07733-2","DOIUrl":"10.1140/epjp/s13360-026-07733-2","url":null,"abstract":"<div><p>Fundamental physics today is best defined operationally: it is the program of identifying the microscopic degrees of freedom, symmetries, and dynamical laws that (i) reproduce the Standard Model (SM) of particle physics, General Relativity (GR), and the <span>(Lambda )</span>CDM cosmological model in their regimes of validity, and (ii) explain the observed phenomena that these baseline theories do not account for (dark matter, neutrino masses, baryogenesis, dark energy), while resolving conceptual inconsistencies (quantum gravity, naturalness, the cosmological constant problem, the measurement problem in quantum theory, information in black holes) and providing predictive unification. This review first lays out the SM+GR+<span>(Lambda )</span>CDM baseline, the best current evidence for its parameters, and the concrete anomalies and missing ingredients. It then surveys the most relevant theoretical directions (effective field theories; amplitude/positivity programs; lattice and many-body methods; symmetry-based model building; cosmological EFTs; quantum information approaches to QFT/gravitation) and the experimental/observational landscape, including ground and space platforms, astronomical messengers, and in-situ tests. Throughout we emphasize: (a) how each observable maps to energy scales and couplings; (b) the dominant statistical and systematic limitations; (c) the sensitivity required for decisive progress. A staged roadmap is given only after the technical review, organized by decision points and cross-checks rather than by specific projects.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829482","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":"Probing vector- versus scalar-mediator dark-matter scenarios in (Brightarrow (K,K^*) M_X) decays","authors":"Alexander Berezhnoy,&nbsp;Wolfgang Lucha,&nbsp;Dmitri Melikhov","doi":"10.1140/epjp/s13360-026-07673-x","DOIUrl":"10.1140/epjp/s13360-026-07673-x","url":null,"abstract":"<div><p>Within the hypothesis of the dark-matter (DM) origin of the excess in <span>(Brightarrow K M_X)</span> decays over the standard-model expectation, observed by Belle II, we report the following results: (i) Combining the available data on the integrated decay rates <span>(Gamma (Brightarrow K M_X))</span> and the upper limit on the integrated decay rates <span>(Gamma (Brightarrow K^* M_X))</span> provides a tight constraint on the vector-mediator mass <span>(M_Vlesssim 3)</span> GeV, whereas no constraints on the scalar-mediator mass are imposed by these data. (ii) Both scalar- and vector-mediator scenarios allow for a good description of the differential distributions in <span>(Brightarrow K M_X)</span> measured by Belle II and an extraction of dark-model parameters within both scenarios. Previously, for the scalar-mediator scenario, we extracted the scalar-mediator parameters <span>(M_phi sim 2.4)</span> GeV, <span>(Gamma _phi sim 2.9)</span> GeV, and the DM fermion mass <span>(m_chi sim 0.42)</span> GeV. We now extract the parameters for the vector-mediator scenario: <span>(M_Vsim 3.0)</span> GeV, <span>(Gamma _Vsim 4.0)</span> GeV, and <span>(m_chi sim 0.6)</span> GeV. (iii) In view of a nice description of the Belle II data in scalar- and vector-mediator scenarios, one faces the problem of discriminating between these scenarios. We propose a novel clear measurable signature to discriminate between two DM scenarios: The ratio of the <i>differential</i> distributions in <span>(Brightarrow K M_X)</span> and <span>(Brightarrow K^* M_X)</span> decays is shown to have qualitatively different shapes for scalar- and vector-mediator scenarios.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-026-07673-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Cross-dimensional controlled bidirectional teleportation via high-dimensional entangled channels","authors":"Fei Huang,&nbsp;Jian-Gang Tang,&nbsp;Miao Liu,&nbsp;Nueraminaimu Maihemuti,&nbsp;Quan-Guo Chen,&nbsp;Jia-Yin Peng","doi":"10.1140/epjp/s13360-026-07710-9","DOIUrl":"10.1140/epjp/s13360-026-07710-9","url":null,"abstract":"<p>We propose a novel protocol for controlled bidirectional teleportation of multi-qubit quantum states using high-dimensional entangled channels. The protocol enables simultaneous exchange of arbitrary unknown single-particle states between two users under supervisory control, with both deterministic and probabilistic implementations. By constructing complete orthogonal non-symmetric bases in <span>((d times f))</span>-dimensional Hilbert space and designing maximally entangled five-particle states, we establish a comprehensive framework for quantum state transmission across different dimensional spaces. Our protocol demonstrates 100% success probability for maximally entangled channels and provides analytical solutions for non-maximally entangled cases. The proposed scheme offers enhanced security and flexibility for future quantum communication networks.</p>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829277","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":"HybridBigDataClassifier: a hybrid deep learning approach for scalable big data classification with imbalanced datasets","authors":"Bhaskar Kantapalli,&nbsp;Markapudi Babu Rao","doi":"10.1140/epjp/s13360-026-07726-1","DOIUrl":"10.1140/epjp/s13360-026-07726-1","url":null,"abstract":"<div><p>While automated classification systems generally thrive in environments with copious high-dimensional data, a characteristic found across diverse fields ranging from healthcare and finance to cybersecurity, the general availability of massive datasets is a double-edged sword. For scalability and generalisation under class imbalance, traditional machine learning algorithms face challenges. Although deep learning models have shown great promise, many current architectures are not designed to operate in a distributed fashion or struggle with class imbalance, as they tend to favour the majority class in skewed distributions. This results in biased predictions and suboptimal performance in critical real-world applications. To overcome these limitations, in this work we introduce HybridBigDataClassifier, a scalable deep learning framework built on Apache Spark, and a new architecture, HybridDeepNet. It comprises residual learning blocks with DQN-like layers to improve feature extraction and decision robustness, while accelerating training convergence. A dynamic class-weighting mechanism is also integrated to mitigate class imbalance during model training, thereby avoiding reliance on external resampling strategies. It is distributed, making it suitable for big data pipelines. The proposed HybridBigDataClassifier, built on the HybridDeepNet architecture, was evaluated on five heterogeneous, imbalance-prone benchmark datasets (healthcare, fraud detection, census income, network intrusion, and e-commerce) and consistently achieved higher accuracy (up to 0.987), F1-score (up to 0.93), and ROC-AUC (up to 0.98) than standard deep models, confirming its suitability for large-scale, imbalanced classification. Experimental results substantiate that, across all primary metrics, HybridDeepNet significantly outperforms state-of-the-art deep learning baselines. Ablation studies confirm the contribution of each component to performance improvements. In conclusion, HybridBigDataClassifier is a novel, highly robust, generalisable, and deployment-ready classifier for over- and under-sampled real-world big-data classification problems, with class imbalance and computational scalability as the dominant pain points. It even emphasises its possible applicability in general areas of intelligent machinery.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829354","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":"Risk assessment and management strategies for radon and thoron exposure in some healthcare environments in Kosovo","authors":"Margarita Kuqali,&nbsp;Ylli Kaçiu,&nbsp;Blerim Rrakaqi,&nbsp;Njomza Elezaj,&nbsp;Gazmend Nafezi","doi":"10.1140/epjp/s13360-026-07738-x","DOIUrl":"10.1140/epjp/s13360-026-07738-x","url":null,"abstract":"<div><p>Indoor exposure to radon (²²²Rn) and thoron (²²⁰Rn) in healthcare environments represents a potential radiological risk for both patients and staff. This study is the first systematic assessment of radon and thoron activity concentrations at the University Clinical Center of Kosovo (QKUK), the largest healthcare facility in the country. Measurements were performed during a 94-day monitoring campaign from early spring to early summer using passive CR-39 diffusion chamber detectors and active real-time monitors (RadonEye RD200). In addition, twin-chamber detectors were paced at selected locations to simultaneously evaluate radon and thoron contributions. Radon concentrations ranged from 24 to 360 Bq m⁻³ with an arithmetic mean of 72 Bq m⁻³, corresponding to estimated annual effective doses between 0.41 and 6.12 mSv y⁻¹. Thoron concentrations varied from 5 to 45 Bq m⁻³, contributing up to 20% of the total alpha activity. Most measured values remained below international reference levels (100 Bq m⁻³ recommended by WHO and 300 Bq m⁻³ defined by the EU Basic Safety Standards), although localized hotspots were identified in basement technical rooms. Seasonal factors and post-war building renovations likely contributed to the observed moderate concentrations. The results highlight the importance of targeted mitigation strategies, particularly improved ventilation and continuous monitoring, to minimize exposure and ensure adequate radiation protection for healthcare workers and patients.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829278","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":"Dynamics of localized waves and interactions for the (3+1)-Dimensional variable-coefficient Kairat-II equation","authors":"Yarong Xia,&nbsp;Xiaoqing Sun,&nbsp;Ruoxia Yao","doi":"10.1140/epjp/s13360-026-07731-4","DOIUrl":"10.1140/epjp/s13360-026-07731-4","url":null,"abstract":"<div><p>This paper investigates the localized wave solutions and their nonlinear dynamical properties of the (3+1)-dimensional variable-coefficient Kairat-II (3DVCK-II) equation. Starting from the constant-coefficient version, we introduce time-dependent coefficients and establish the integrability of the resulting equation via the Painlevé test. Using the Hirota bilinear method, we derive higher-order kink solutions, breather solutions, lump-type solutions, and several hybrid solutions. By considering different functional forms of the time-varying coefficients—such as piecewise trigonometric, hyperbolic and polynomial functions, we systematically analyze the physical effects of these variable coefficients on wave propagation trajectories, symmetry and energy dissipation. Graphical illustrations including three-dimensional and density plots are provided to visualize the dynamic behaviors. Furthermore, to rigorously verify the accuracy of the analytical solutions and the physical stability of the localized waves, deep learning based numerical simulations are conducted using Physics-Informed Neural Networks (PINN). The results demonstrate that variable coefficients significantly enrich the solution structures, offering deeper insights into the nonlinear wave phenomena described by the model.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829276","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":"Non-local material vacuum and Cherenkov radiation in nonlinear massive 3D Electrodynamics","authors":"Patricio Gaete,&nbsp;J. A. Helayël-Neto","doi":"10.1140/epjp/s13360-026-07729-y","DOIUrl":"10.1140/epjp/s13360-026-07729-y","url":null,"abstract":"<div><p>We examine the effects of electromagnetic field nonlinearities in 3 space-time dimensions. We focus on how these nonlinearities influence permittivity and susceptibility. This, in turn, leads to changes in the refractive index through the use of the dispersion relation in the context of massless and massive nonlinear electrodynamics. We also verify that, by inspecting the model addressed in the frequency/wave vector space, we identify the characteristics of a non-local material in the behavior of the vacuum, which exhibits a spatially dispersive profile. Furthermore, it is important to highlight that the cause of this phenomenon is the de Broglie–Proca mass term. We subsequently investigate the electromagnetic radiation emitted by a moving charged particle interacting with a medium for massless and massive nonlinear electrodynamics. Our findings indicate that the radiation is driven by the medium through which the particle travels, similar to what is observed in the Cherenkov effect.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829216","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":"Thermal performance enhancement of a double tube heat exchanger using ternary nanofluid and disk-type turbulators: a numerical study","authors":"Nabil Jlidi,&nbsp;Zouhaier Mehrez,&nbsp;Afif El Cafsi","doi":"10.1140/epjp/s13360-026-07721-6","DOIUrl":"10.1140/epjp/s13360-026-07721-6","url":null,"abstract":"<div><p>Improving the efficiency of compact heat exchangers is essential for modern thermal systems facing strict energy and cost constraints. This study introduces a CFD-based analysis of a counterflow double tube heat exchanger enhanced by both ternary hybrid nanofluids and disk-type turbulators. The working fluid combines CuO, CaCO₃, and SiO₂ nanoparticles dispersed in distilled water, with temperature-dependent thermophysical properties. Three tube configurations were tested: a smooth inner tube, a tube with solid hollow disk inserts, and a tube with perforated disk turbulators, aimed at maximizing turbulence intensity and heat transfer. The simulations, conducted via the finite volume method using the standard k–ε model, span Reynolds numbers from 3424 to 11,985 and nanoparticle volume fractions up to 0.4%. Validation was performed using experimental and empirical benchmarks. Results demonstrate that the combination of hybrid nanofluids and turbulence promoters yields a synergistic thermal enhancement: the convective heat transfer coefficient increased by up to 194.2%, and the overall heat transfer coefficient by 191.1%. The perforated disk design achieved a maximum 140% increase in the  thermal performance factor, confirming the potential of ternary nanofluids with optimized turbulators for next-generation heat exchanger applications.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829260","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":"Dynamical behavior of a four-dimensional discrete fractional-order polynomial chaotic map and its applications: image encryption and FPGA implementation","authors":"Binshuai Feng,&nbsp;Xuehui Bai,&nbsp;Jingxuan Feng,&nbsp;Zeyu Liu,&nbsp;Songlin Jiang","doi":"10.1140/epjp/s13360-026-07699-1","DOIUrl":"10.1140/epjp/s13360-026-07699-1","url":null,"abstract":"<div><p>A detailed analysis encompassing chaotic trajectories, Lyapunov exponents, and equilibrium points is conducted to investigate the dynamic characteristics and identify hidden attractors of the proposed four-dimensional discrete fractional-order polynomial chaotic map. The implementation of discrete fractional-order chaotic systems with memory effects on hardware with limited resources is intriguing but challenging. Conventional engineering approaches tend to implement such systems in the frequency domain using Z-transform. However, this study proposes an alternative time-domain FPGA implementation based on the theory of short-memory fractional difference equations. The proposed implementation successfully generates chaotic sequences, with their accuracy verified through numerical simulations. In addition, we develop a novel chaotic synchronization control law based on stability criteria for fractional difference equations. The system is further extended to implement chaos-based image encryption. The experimental results demonstrate that the FPGA-implemented chaotic encryption system achieves satisfactory performance with a considerably large key space. It is noteworthy that the two synchronized systems can be utilized separately for image encryption and decryption processes, respectively, thereby enhancing the algorithm’s security. In practice, short-memory difference equations offer computational advantages by reducing memory requirements.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 5","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147829198","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}