The European Physical Journal Plus最新文献

{"title":"Optimal performance of a heat engine for a parallelly connected two quantum dots","authors":"Asmamaw Tesega","doi":"10.1140/epjp/s13360-025-06143-0","DOIUrl":"10.1140/epjp/s13360-025-06143-0","url":null,"abstract":"<div><p>In this paper, we developed a model of a heat engine that consists of two single-level quantum dots that are coupled in parallel and sandwiched between two thermal reservoirs with varying chemical potentials and temperatures. The difference in chemical potential and temperature facilitates the cyclical movement of electrons and acts as a heat engine. We investigate how thermodynamic quantities like heat, work, and efficiency are evaluated as a function of scaled energy. We also carried out analytical and numerical solutions for optimum scaled energies and the corresponding optimum efficiency of the thermoelectric heat engine. Therefore, the two optimum efficiencies are constrained below by the efficiency at maximum power output (<span>(eta ^*)</span>), the Curzon-Ahlborn efficiency (<span>(eta _{CA})</span>), and above by the Carnot efficiency (<span>(eta _C)</span>). Besides, we assess the overall optimal performance of a heat engine by introducing a figure of merit. Based on the proposed figure of merit, our result shows that the second optimization criteria exhibits superior performance compared to the first optimization criteria across the full range of Carnot efficiency.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521598","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":"Schwarzschild black-hole immersed in an electric or magnetic background in Entangled Relativity","authors":"Olivier Minazzoli,&nbsp;Maxime Wavasseur","doi":"10.1140/epjp/s13360-025-06129-y","DOIUrl":"10.1140/epjp/s13360-025-06129-y","url":null,"abstract":"<div><p>In this paper, we present the solution for a Schwarzschild black-hole immersed in an electric or magnetic background field à la Melvin within the framework of Entangled Relativity. Previous solutions in Entangled Relativity required black-holes to be charged for the matter field to be defined everywhere. This is because the theory precludes the existence of vacuum solutions, thereby satisfying Einstein’s definition of Mach’s Principle. The current black-hole solutions represent the first exact and neutral black-hole solutions of Entangled Relativity discovered to date. The Schwarzschild black-hole of General Relativity emerges as a limit of these solutions when the background field approaches zero, whereas the Melvin solution of General Relativity does not emerge as a limit when the black hole’s size approaches zero. This finding suggests that astrophysical black-holes in Entangled Relativity are indistinguishable from those in General Relativity, given the generally weak interstellar density of matter fields.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513265","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":"Switchable regulation of a polymodal auditory network with information transmission and phase synchronization","authors":"Guodong Huang,&nbsp;Shu Zhou,&nbsp;Yuan Chai,&nbsp;Suyuan Huang,&nbsp;Zhenpu Liu","doi":"10.1140/epjp/s13360-025-06136-z","DOIUrl":"10.1140/epjp/s13360-025-06136-z","url":null,"abstract":"<div><p>Switchable regulation plays an important role in information encoding in the nervous system. An appropriate level of chaotic activity can enhance the encoding of weak signals in neurons, the phenomenon known as chaotic resonance (CR). However, previous studies of CR focused on single neurons without polymodal network. Therefore, to investigate how chaotic activities of switchable regulation affect the transmission of weak signals and neuronal synchronization across multi-mode pathways, this paper proposes a polymodal auditory network, with communication function combining auditory neurons and central neurons. It is shown that regardless of the currents, electric fields, and magnetic fields, chaotic activity can effectively enhance the information transmission between neurons. The enhancement regulation of CR in information transmission is realized by controlling signal frequency and current intensity, regulating multi-mode pathways. Furthermore, the enhancement of phase synchronization in polymodal auditory networks by chaotic activities is revealed, and synchronization and de-synchronization between neurons can be achieved through the adjustment of relevant parameters or the switching of pathways. The research offers insights into how chaotic activities influence information transmission and phase synchronization within neural systems, and provides guidance for the switchable regulation of artificial biological synapses and the polymodal development of brain–computer interfaces.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513264","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":"Internal complexity feature and similarity of the gamma monitoring time series acquired in the environment by two different detection systems","authors":"Senada Avdic,&nbsp;Suad Kunosic","doi":"10.1140/epjp/s13360-025-06139-w","DOIUrl":"10.1140/epjp/s13360-025-06139-w","url":null,"abstract":"<div><p>The early warning network for continuous monitoring of radiation level in the environment provides the relevant information on the radiation levels in regular conditions and in case of a radiological or nuclear emergency. An automatic gamma radiation monitoring network in Bosnia and Herzegovina consists of two smaller systems based on the MFM-203 and GammaTRACER XL2 monitors. In order to investigate the comparability and reliability of the ambient dose equivalent rate data acquired at all the monitoring stations based on two different detection systems, we have quantified the natural fluctuations and internal features of the investigated time series. It was demonstrated that the data recorded at the GammaTRACER XL2 stations show the larger fluctuations compared to the data collected at the MFM-203 stations in the same period of time. We have applied the DTW measure as an advanced distance measure, and it was observed that two time series show the similarity since the DTW outputs obtained are within the DTW output ranges due to the natural fluctuations that were recorded with the same instrument. The results of the internal complexity feature analysis show that the gamma dose rate time series measured at the GammaTRACER XL2 stations are somewhat less random than the MFM-203 experimental time series. It was observed that there is an overlapping to some extent between the results of complexity dynamics analysis for both time series. The results of the present study show that all the ambient gamma dose rates measured with two different detection systems can be considered comparable and reliable. Such results are of interest for a proper interpretation of the background radiation level data acquired in the environment in regular conditions as well as in accidental situations.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521611","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":"Liénard-Wiechert potentials due to a ‘classically’ spinning point-charge in non-relativistic arbitrary motion","authors":"Nikhil D. Hadap","doi":"10.1140/epjp/s13360-025-06089-3","DOIUrl":"10.1140/epjp/s13360-025-06089-3","url":null,"abstract":"<div><p>Liénard-Wiechert potentials have been derived for a moving and ‘classically’ spinning point-charge; assuming it to be a small rigid charged-sphere in combined non-relativistic translational and rotational motion, and subsequently reducing its dimensions to ‘point-particle’ limit. The paper demonstrates that when the effect of rotation were taken into account, together with causality, expressions for the LW potentials accompany additional correction terms that contain spin angular momentum (or simply the ‘classical-spin’) of the point-charge.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06089-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513327","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":"Do heavy monopoles hide from us?","authors":"Huner Fanchiotti,&nbsp;C. A. García Canal,&nbsp;Vicente Vento","doi":"10.1140/epjp/s13360-025-06115-4","DOIUrl":"10.1140/epjp/s13360-025-06115-4","url":null,"abstract":"<div><p>Dirac demonstrated that the existence of a single magnetic monopole in the universe could explain the discrete nature of electric charge. Magnetic monopoles naturally arise in most grand unified theories. However, the extensive experimental searches conducted thus far have not been successful. Here, we propose a mechanism in which magnetic monopoles bind deeply with neutral states, effectively hiding some of the properties of free monopoles. We explore various scenarios for these systems and analyze their detectability. In particular, one scenario is especially interesting, as it predicts a light state—an analog of an electron but with magnetic charge instead of electric charge—which we refer to as a <i>magnetron</i>.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06115-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513326","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":"Novel intelligent neuro-structure optimized Bayesian distributed backpropagation for magnetohydrodynamics flow analysis of double-layer optical fiber coating","authors":"Sayyed Talha Gohar Naqvi,&nbsp;Saeed Ehsan Awan,&nbsp;Muhammad Asif Zahoor Raja,&nbsp;Shahab Ahmad Niazi","doi":"10.1140/epjp/s13360-025-06097-3","DOIUrl":"10.1140/epjp/s13360-025-06097-3","url":null,"abstract":"<div><p>Double-layer coated optical fibers provide vital protection against signal attenuation and mechanical damage, necessitating coatings that offer comprehensive surface coverage to meet stringent mechanical, chemical, and electrical standards. In the current study, a pressure-type die is utilized to coat double-layer optical fibers along with molten polymer, conforming to the Oldroyd 8-constant fluid model. The presented investigation analyzes the influence of magnetohydrodynamic effects during the coating process by leveraging a novel design of intelligent Bayesian regularization scheme (IBRS) to effectively investigate several important physical aspects. Adams numerical solver is employed to solve the associated differential systems, generating reference datasets for a double-layer optical fiber-coated model under various scenarios by variation of wall magnetic parameter, dilatant constant, pseudoplastic constant, and pressure gradient. These parameters play a vital role in enhancing the thickness of coated optical fibers, thereby implying their potential use as controlling parameters for thickness regulation. An intelligent solution strategy is implemented by using supervised artificial neural networks with IBRS. This approach enables immediate numerical approximation outcomes through simulations conducted on training, testing, and validation samples derived from reference datasets of complex geometry. The reliability of the IBRS networks is confirmed through convergence plots depicting mean squared errors (MSEs), effective outputs indicating adaptive control parameters of the optimization algorithm, and histograms based on errors and regression statistics derived from comprehensive simulation studies across several scenarios.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496842","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":"Development of an epithermal and fast neutron target station for the High Brilliance Neutron Source","authors":"Norberto Sebastián Schmidt,&nbsp;Doruntin Shabani,&nbsp;Jingjing Li,&nbsp;Paul Zakalek,&nbsp;Eric Mauerhofer,&nbsp;Javier Dawidowski,&nbsp;Thomas Gutberlet","doi":"10.1140/epjp/s13360-025-06100-x","DOIUrl":"10.1140/epjp/s13360-025-06100-x","url":null,"abstract":"<div><p>The conceptual design of an epithermal and fast neutron target–moderator–reflector (TMR) unit for the High Brilliance Neutron Source (HBS) project is presented. A total of 450 simulations with the Monte Carlo code <span>PHITS</span> were analyzed to explore different combinations and thicknesses of pre-moderator and moderator materials. For each case, the highest epithermal outgoing neutron current at the end of an extraction channel was obtained. Analysis of the outgoing current density showed that the neutron spectra are independent of the proton pulse width, while the integral outgoing current is proportional to the pulse width, indicating a trade-off between the time resolution obtained and the neutron flux per pulse expected at the sample position. The neutron time distribution analysis showed that <span>(hbox {D}_2)</span>O as pre-moderator, combined with <span>(hbox {D}_2)</span>O, ⁷LiF or graphite as moderators, will provide a competitive epithermal neutron current. The averaged epithermal and fast values obtained for the 96 Hz station and 167 <span>(upmu )</span>s proton pulse width are <span>(9 times 10^{9},hbox {cm}^{-2},hbox {s}^{-1})</span> and <span>(2 times 10^{10},hbox {cm}^{-2},hbox {s}^{-1})</span> for the epithermal and fast neutron extraction channels, respectively, with reductions expected for short proton pulses in burst-mode operation.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06100-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513325","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":"Scaling laws for optimal turbulent flow in tree-like networks with smooth and rough tubes and power-law fluids","authors":"Ashish Garg,&nbsp;Himanshu Mishra,&nbsp;Jayati Sarkar,&nbsp;Sudip K. Pattanayek","doi":"10.1140/epjp/s13360-025-06109-2","DOIUrl":"10.1140/epjp/s13360-025-06109-2","url":null,"abstract":"&lt;div&gt;&lt;p&gt;In this paper, we establish optimized scaling laws for fully-developed turbulent flows of incompressible power-law fluids with index &lt;i&gt;n&lt;/i&gt; within tree-like branching networks. Our analysis considers turbulence in both smooth and rough channels while accounting for constraints on the network’s volume and surface area. To characterize flow conditions, we introduce a dimensionless conductance parameter, &lt;i&gt;E&lt;/i&gt;, and examine its dependence on the diameter ratio &lt;span&gt;(beta )&lt;/span&gt;, branch splitting &lt;i&gt;N&lt;/i&gt;, length ratio &lt;span&gt;(gamma )&lt;/span&gt;, and the number of branching generations &lt;i&gt;m&lt;/i&gt;. The results indicate that &lt;i&gt;E&lt;/i&gt; decreases as &lt;span&gt;(gamma )&lt;/span&gt;, &lt;i&gt;N&lt;/i&gt;, and &lt;i&gt;m&lt;/i&gt; increase, underscoring the impact of these factors on flow conductance. Furthermore, under volume constraints, we determine the optimal conditions for flow in both smooth and rough tube fractal networks, leading to distinct scaling relationships as &lt;span&gt;(displaystyle frac{D_{k+1}}{D_{k}} = beta ^* = N^{-(10n+1)/(24n+3)} )&lt;/span&gt;, and &lt;span&gt;(displaystyle frac{D_{k+1}}{D_{k}} = N^{-3/7} )&lt;/span&gt; (or &lt;span&gt;(dot{m}_k propto D_k^{(24n+3)/(10n+1)})&lt;/span&gt; and &lt;span&gt;(dot{m}_k propto D_k^{7/3})&lt;/span&gt; ), respectively, where &lt;span&gt;( D_k )&lt;/span&gt; represents the tube diameter and &lt;span&gt;( dot{m}_k )&lt;/span&gt; denotes the mass flow rate at the &lt;span&gt;( k )&lt;/span&gt;th branching level. Interestingly, in rough tube networks, the scaling behavior remains unaffected by the fluid index &lt;span&gt;( n )&lt;/span&gt;, whereas in smooth tube networks, it exhibits a dependence on &lt;span&gt;( n )&lt;/span&gt;. Likewise, when constrained by surface area, the optimal flow conditions vary between smooth and rough tube networks, each following distinct scaling laws as &lt;span&gt;(displaystyle frac{D_{k+1}}{D_{k}} = beta ^* = N^{-(10n+1)/(21n+2)} )&lt;/span&gt;, and &lt;span&gt;(displaystyle frac{D_{k+1}}{D_{k}} = N^{-1/2} )&lt;/span&gt; (or &lt;span&gt;(dot{m}_k propto D_k^{(21n+2)/(10n+1)})&lt;/span&gt; and &lt;span&gt;(dot{m}_k propto D_k^{2})&lt;/span&gt; ), respectively. The smooth tube network once again exhibits dependence on the fluid index &lt;span&gt;( n )&lt;/span&gt;. Furthermore, our analysis reveals that in volume-constrained networks, the scaling exponent slope decreases as &lt;span&gt;( n )&lt;/span&gt; increases, whereas in surface-area-constrained networks, the trend is reversed. We find that the optimal flow condition aligns with the uniform distribution of pressure drop across each branching level within the network. This applies under both constraints for turbulent flow behavior in both smooth and rough-walled tubes. We validated our results against various previous theoretical predictions under limiting conditions. Additionally, this study explores the interplay between geometric and flow properties of parent and daughter tubes in branching networks. Furthermore, we also establish extended scaling-laws under optimal conditions, addressing critical parameters such as length ratios, average flow velocities, tube-volume, and surface-area within the fractal netwo","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489627","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":"Electric quadrupole transitions of triaxial nuclei via the Bohr Hamiltonian within the screened Kratzer–Hellmann potential","authors":"D. Nga Ongodo,&nbsp;A. A. Atangana Likéné,&nbsp;A. Zarma,&nbsp;S. Haman Adama,&nbsp;J. M. Ema’a Ema’a,&nbsp;G. H. Ben-Bolie","doi":"10.1140/epjp/s13360-025-06066-w","DOIUrl":"10.1140/epjp/s13360-025-06066-w","url":null,"abstract":"<div><p>This paper proposes an innovative potential model, based on factorization with a screening term. The latter potential offers a rich and versatile framework that encompasses various classical potentials such as Coulomb, Kratzer, Yukawa, Hellmann and screened Kratzer potentials. This generalization makes our model particularly suitable for comprehensive studies of nuclear structure. After the exact separation of the Bohr Hamiltonian equation into its variables, the parametric Nikiforov–Uvarov (NU) method is employed, involving Greene–Aldrich approximation, to calculate the energy eigenvalues and wave functions. The results of the calculations are used to estimate the normalized energies of the low-lying states and the B(E2) transition rates of <span>(^{192,194,196})</span>Pt and <span>(^{128,130,132})</span>Xe isotopes. To assess the reliability of our model on the investigated isotopes, the numerical values of energy spectra and electric quadrupole transition rates are compared to experimental data and other relevant theoretical works. As evidenced by the values of the root mean square, our findings show excellent agreement with experimental data, underscoring the robustness and accuracy of our approach and the significance of the newly introduced potential.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496807","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}