物理最新文献

{"title":"Sensitive shock tube measurements using multipass laser absorption spectroscopy","authors":"Haojia Sun,&nbsp;Mohsin Raza,&nbsp;Sihao Wang,&nbsp;Dapeng Liu,&nbsp;Daxin Wen,&nbsp;Hongbo Ning,&nbsp;Wei Ren","doi":"10.1007/s00340-025-08545-5","DOIUrl":"10.1007/s00340-025-08545-5","url":null,"abstract":"<div><p>We report a sensitive laser absorption diagnostic method for shock tube experiments using a multipass configuration with a single-line spot pattern. The multipass setup consists of two silver-coated concave mirrors, which are placed outside the optical windows of the shock tube. The multipass configuration increases the effective path length by a factor of 31. All the reflected beams are aligned within a single plane that is perpendicular to the propagation direction of the shock wave, mitigating the Schlieren and beam steering effects. We validated the approach by measuring shock-heated gases behind reflected shock waves using tunable laser absorption spectroscopy of water vapor at 7447.48 cm^− 1. Our approach enables sensitive species detection for high-temperature shock tube/laser absorption experiments.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"131 9","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00340-025-08545-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923160","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":"Probing stability of dark matter sustained wormholes in matter-curvature coupled gravity","authors":"Zinnat Hassan,&nbsp;Aaqid Bhat,&nbsp;P. K. Sahoo","doi":"10.1140/epjc/s10052-025-14665-1","DOIUrl":"10.1140/epjc/s10052-025-14665-1","url":null,"abstract":"<div><p>We investigate traversable wormhole solutions sustained by dark matter in the context of curvature-matter coupled gravity, specifically the <span>(f(R, mathcal {L}_m, T))</span> theory. By analyzing the traversability criteria, we identify constraints on the model parameters that ensure physically viable, asymptotically flat wormhole geometries. Our results show that while small values of the dark matter density <span>(rho _s)</span> preserve asymptotic flatness, larger values of the coupling parameter <span>(beta )</span> may violate the flare-out condition. Furthermore, we find that the null energy condition is violated near the throat <span>( r=r_0)</span>, indicating the effective role of the modified gravity terms as a source of exotic matter. To examine the stability and physical possibility of the solutions, we perform a comprehensive analysis involving gravitational lensing, the complexity factor, the anisotropy parameter, active gravitational mass, total gravitational energy, and the volume integral quantifier. Our findings demonstrate that stable, traversable wormholes can emerge within specific parameter regimes in this framework with minimal exotic matter, offering new insights into the interplay between dark matter and modified gravity.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14665-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923288","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":"Extended geometric trinity of gravity","authors":"Salvatore Capozziello,&nbsp;Sara Cesare,&nbsp;Carmen Ferrara","doi":"10.1140/epjc/s10052-025-14440-2","DOIUrl":"10.1140/epjc/s10052-025-14440-2","url":null,"abstract":"<div><p>Extensions of equivalent representations of gravity are discussed in the metric-affine framework. First, we focus on: (i) General Relativity, based upon the metric tensor whose dynamics is given by the Ricci curvature scalar <i>R</i>; (ii) the Teleparallel Equivalent of General Relativity, based on tetrads and spin connection whose dynamics is given by the torsion scalar <i>T</i>; (iii) the Symmetric Teleparallel Equivalent of General Relativity, formulated with respect to both the metric tensor and the affine connection and characterized by the non-metric scalar <i>Q</i> with the role of gravitational field. They represent the so-called Geometric Trinity of Gravity, because, even if based on different frameworks and different dynamical variables, such as curvature, torsion, and non-metricity, they express the same gravitational dynamics. Starting from this framework, we construct their extensions with the aim to study possible equivalence. We discuss the straightforward extension of General Relativity, the <i>f</i>(<i>R</i>) gravity, where <i>f</i>(<i>R</i>) is an arbitrary function of the Ricci scalar. With this paradigm in mind, we take into account <i>f</i>(<i>T</i>) and <i>f</i>(<i>Q</i>) extensions showing that they are not equivalent to <i>f</i>(<i>R</i>). Dynamical equivalence is achieved if boundary terms are considered, that is <span>(f(T-tilde{B}))</span> and <span>(f(Q-B))</span> theories. The latter are the extensions of Teleparallel Equivalent of General Relativity and Symmetric Teleparallel of General Relativity, respectively. We obtain that <i>f</i>(<i>R</i>), <span>(f(T-tilde{B}))</span>, and <span>(f(Q-B))</span> form the Extended Geometric Trinity of Gravity. The aim is to show that also if dynamics are equivalent, foundations of theories of gravity can be very different.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14440-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927157","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":"Synchronization of the time-delayed Kuramoto model in a regular network","authors":"Sara Ameli,&nbsp;Esmaeil Mahdavi,&nbsp;Mina Zarei,&nbsp;Farhad Shahbazi","doi":"10.1140/epjp/s13360-025-06457-z","DOIUrl":"10.1140/epjp/s13360-025-06457-z","url":null,"abstract":"<div><p>This study investigates the impact of delayed coupling on the global and local synchronization of identical coupled oscillators residing in a ring. Utilizing the Kuramoto model, we examine the effects of delayed coupling on collective dynamics. Our analytical and numerical results reveal distinct synchronization behaviors across various time delay regimes, including fully synchronized states, helical patterns, dynamically incoherent states, and random phase-locked states. We identify the regime in which time delay inhibits synchrony, which aligns with theoretical predictions derived from stability analysis. In the region between the synchrony-possible and synchrony-forbidden zones, a coexistence of synchronized and unsynchronized dynamics is observed, referred to as chimera states. We ascertain that the type of chimera states present is moving turbulent.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06457-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927037","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":"Coherent detection of discrete variable quantum key distribution using homodyne technique","authors":"Muhammad Kamran,&nbsp;Tahir Malik,&nbsp;Ayesha Jamal,&nbsp;Muhammad Fahim Ul Haque,&nbsp;Muhammad Mubashir Khan","doi":"10.1007/s00340-025-08531-x","DOIUrl":"10.1007/s00340-025-08531-x","url":null,"abstract":"<div><p>In discrete variable quantum key distribution (DV-QKD), the homodyne detection method is frequently employed for its simplicity in use, effectiveness in terms of error correction, and suitability with contemporary optical communication systems. Being a coherent detection method, it relies on a local oscillator whose frequency is matched to that of the transmitted carrier’s signal. In this paper, we evaluate a free space optical (FSO) DV-QKD system based on the KMB09 protocol using Homodyne detection under random phase fluctuation and depolarizing noise error. We present simulation results for system efficiency and quantum bit error rate (QBER) for the proposed model. An obtained efficiency (<span>(25%)</span>) for our proposed DV-QKD system model shows that under atmospheric turbulence and noise effect and it is in line with the available analytical results. However, the inclusion of random phase fluctuation and noise led to higher-than-normal QBER which is anticipated in a real-world scenario.</p></div>","PeriodicalId":474,"journal":{"name":"Applied Physics B","volume":"131 9","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923159","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":"Characteristic precessions of spherical orbit around a rotating braneworld black hole","authors":"Hui-Min Wang,&nbsp;Kai Liao,&nbsp;Shao-Wen Wei","doi":"10.1140/epjc/s10052-025-14626-8","DOIUrl":"10.1140/epjc/s10052-025-14626-8","url":null,"abstract":"<div><p>We study the orbital dynamics and relativistic precession effects in the spacetime of rotating braneworld black holes within the Randall–Sundrum framework. For test particles on spherical orbits, we analyze three conserved quantities – energy, angular momentum, and Carter constant – and examine how the innermost stable spherical orbit depends on the tidal charge and orbital inclination. Compared to Kerr black holes, braneworld corrections significantly modify both nodal and periastron precession frequencies: positive tidal charges suppress precession rates, while negative charges enhance them. For stationary gyroscopes, we calculate the Lense–Thirring precession frequency and demonstrate its sensitivity to the tidal charge, black hole spin, and gyroscope orientation. Our results show that a positive tidal charge weakens frame-dragging effects even as it enhances gravitational attraction – offering a distinctive signature of extra-dimensional gravity. These results have important implications for astrophysical observations, including accretion disk behavior, stellar orbital dynamics, and gravitational wave detection. The modified orbital and gyroscopic precession provide new ways to test braneworld gravity in strong-field regimes.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 9","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14626-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927156","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":"A comparative study on antimicrobial efficacy of non-metallic S, SiO2 and S@SiO2 core–shell nanoparticles","authors":"Divyansha Singh,&nbsp;Deepika P Joshi,&nbsp;Pankaj Singh Rawat","doi":"10.1007/s12043-025-02972-x","DOIUrl":"10.1007/s12043-025-02972-x","url":null,"abstract":"<div><p>The present work aims to investigate the antimicrobial efficacy of non-metallic sulphur, silica and S@SiO₂ core–shell nanoparticles. The X-ray diffraction (XRD) pattern confirmed that the silica nanoparticles have an amorphous structure. In contrast, the sulphur nanoparticles have a crystalline nature with an orthorhombic α-phase structure and S@SiO₂ nanoparticles suggest the superposition of silica XRD pattern on that of sulphur. UV–Visible spectra of silica, sulphur and S@SiO₂ show the highest absorption peak at 293, 326 and 305 nm, respectively. Fourier-transform infrared spectroscopy (FTIR) spectra of core–shell NPs show the presence of sulphur and silica in the core–shell nanoparticles without any chemical interaction between them. The field-emission scanning electron microscopy (FE-SEM) images revealed that the silica nanoparticles are of uniform spherical shape and the average particle size is approximately 250 nm. The shape of the sulphur nanoparticles was found to be irregular and the average particle size was found to be around 130 nm. The FE-SEM images of the core–shell nanoparticles confirmed the regular spherical shape of S@SiO₂ core–shell nanoparticles with an average particle size of approximately 350 nm. The antimicrobial properties of all the synthesised nanoparticles were examined against animal pathogenic gram-negative bacteria, <i>Escherichia coli</i>, <i>Salmonella</i> and plant pathogenic gram-negative bacteria such as <i>Erwinia amylovora</i>, <i>Xanthomonas oryzae</i> by using agar disk diffusion method. The result shows that uncoated and coated nanoparticles substantially inhibit all the gram-negative bacteria. The results demonstrate that the silica and sulphur nanoparticles show effective antimicrobial efficacy against all the specified bacteria, with concentrations of 1500 and 2000 <i>µ</i>g<span>(/)</span>ml being the most effective.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920482","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":"Spherically symmetric vacuum solutions of modified field equations in (f(R, Sigma , T))-gravity","authors":"M Khater,&nbsp;M A Bakry","doi":"10.1007/s12043-025-02996-3","DOIUrl":"10.1007/s12043-025-02996-3","url":null,"abstract":"<div><p>This study examines spherically symmetric static empty space solutions within the framework of the <span>(f(R, Sigma , T))</span>-gravity, where <span>(f(R, Sigma , T))</span> is a general function of the scalar curvature <i>R</i>, the torsion scalar <span>(Sigma )</span> and the trace of the energy–momentum tensor <i>T</i>.\u0000 We reduce the modified Einstein equations to a single equation and demonstrate how to construct exact solutions across various <span>(f(R, Sigma , T))</span>-gravity models. Notably, we establish that for a broad class of models, including the <span>(f(R, Sigma , T)=R+Sigma +2 eta T)</span> model, the Schwarzschild metric serves as an exact solution to the field equations, alongside other classes of solutions. We discuss the significance of these findings in the context of solar system constraints on <span>(f(R, Sigma , T))</span> theories of gravity. Additionally, the effects of space–time torsion and particle spin on the solar system are also explored.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920506","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":"Numerical analysis of the micropolar fluid flow over a permeable stretching sheet with magnetic field effects","authors":"Bandita Das,&nbsp;Sunmoni Mudoi,&nbsp;Chinmoy Dutta,&nbsp;Pranjal Saikia","doi":"10.1007/s12043-025-02978-5","DOIUrl":"10.1007/s12043-025-02978-5","url":null,"abstract":"<div><p>This study explores the effects of MHD and slip velocity on micropolar fluid flow, heat transfer and mass transport over a stretching sheet with heat generation. The impacts of heat generation, thermal conductivity, heat flux, micro-rotation, Prandtl number and Schmidt number were investigated analytically. Similarity transformation is applied to convert the governing partial differential equations into a system of nonlinear ordinary differential equations, which are then solved numerically using the bvp4c method. Graphics are used to illustrate the impact of the relevant parameter on the distribution of velocity, micro-rotation, temperature and concentration. Validation of the solutions is done for some specific cases. Additionally, the consequences of several parameters on the skin friction caused by the primary velocity, Nusselt number and Sherwood number are shown in tabular form. A thorough description and summary of the numerical results for key flow parameters, including the local skin-friction coefficient, wall couple stress and local Nusselt number, are presented in tables. Microparticles have a significant effect on the flow phenomenon. The results are interpreted in detail. This research relates to enhancing electromagnetic fluid management, heat exchangers and industrial processes.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920507","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":"Impact of dispersion modulations on nonlocal coupled solitons in inhomogeneous media","authors":"A. Saparbekova,&nbsp;K. Manikandan,&nbsp;N. Serikbayev","doi":"10.1140/epjp/s13360-025-06742-x","DOIUrl":"10.1140/epjp/s13360-025-06742-x","url":null,"abstract":"<div><p>This study explores the inhomogeneous coupled nonlocal nonlinear Schrödinger equations, which describe soliton dynamics in birefringent optical fibers with longitudinally varying dispersion, nonlinearity, and gain/loss effects. By employing the similarity transformation technique, we convert the inhomogeneous system into its constant coefficient counterpart, allowing us to derive explicit nonlocal soliton solutions. To understand the influence of dispersion variations on inhomogeneous nonlocal solitons, four distinct dispersion modulations are considered: constant, periodic, exponential, and a combined periodic-exponential form. Our findings reveal various soliton behaviors, including breathing dynamics, monotonic and nonmonotonic intensity variations, and oscillatory shifts in the soliton’s central position. Through asymptotic analysis, we investigate the stability characteristics of nonlocal solitons and elucidate the impact of dispersion parameters on their dynamical evolutions. These results provide deeper insights into soliton evolution in inhomogeneous optical media and have potential applications in the design and optimization of fiber laser systems.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920544","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}