物理最新文献

{"title":"Enhanced radiation protection: investigating the efficacy of polychloroprene filled with copper","authors":"Enayatolah Yazdankish","doi":"10.1140/epjp/s13360-025-06730-1","DOIUrl":"10.1140/epjp/s13360-025-06730-1","url":null,"abstract":"<div><p>Lead has long been a commonly used material for radiation protection; however, its toxicity, weight, and flexibility limitations have prompted the exploration of alternative materials. This study focuses on Polychloroprene reinforced with varying weight fractions (10%, 20%, and 40%) of copper as a potential substitute. Utilizing the PY-MLBUF program, we evaluated key parameters including mass attenuation coefficient, linear attenuation coefficient, half-value layer, tenth value layer, atomic effective number, and electron effective number. Increasing the weight fraction of copper in the composite led to higher mass and linear attenuation coefficients while reducing the half-value and tenth value layers. Compared to lead, the radiation protection performance of the selected composites, particularly in terms of mass attenuation, displayed favorable results. Notably, within the energy range of 0.7–4 MeV, where Compton scattering dominates, the differences in mass attenuation coefficients between lead and the composites are minimal. At higher energies, where pair production becomes significant, and at lower energies, where the photoelectric effect dominates, the differences with lead increase; however, for the composite containing 40% copper, the attenuation performance remains within an acceptable range. Hence, for applications within this energy range, using Polychloroprene reinforced with copper emerges as a viable and effective choice.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858582","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":"Enhancement in superluminal propagation and tunability from superluminal to subluminal propagation of a light pulse by heat loss and heat gain","authors":"Ibrahim Khan,&nbsp;Salah Uddin,&nbsp;Sohail Ahmad,&nbsp;Yamin Shah,&nbsp;Kefayat Ullah,&nbsp;Amin ur Rashid","doi":"10.1140/epjp/s13360-025-06703-4","DOIUrl":"10.1140/epjp/s13360-025-06703-4","url":null,"abstract":"<div><p>The subluminal and superluminal propagation of a light pulse has been investigated under the conditions of heat gain and heat loss in a four-level sodium atomic medium. We found a significant enhancement in the superluminal propagation of light with heat gain and heat loss. The negative group index is increased from − 9500 to − 14,000 and shifted to the positive/negative detuning region at heat gain/loss of <span>(Q = pm 2J)</span>. The superluminal group velocity increases from <span>(v_{{text{g}}} = - ;c/9500)</span> to <span>(v_{{text{g}}} = - ;c/14{,}000)</span> along with a shift to the positive/negative detuning region at a heat gain/loss of <span>(Q = pm 2J)</span>. The superluminal propagation is tuned to subluminal propagation with variation in control field Rabi frequencies. Furthermore, the subluminality is also enhanced with heat gain/loss and the collective phase of the control coupled driving fields. These findings may be useful in computer processing and medical imaging.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858573","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":"Thermomechanical properties of R12-graphene nanosheet using molecular dynamics simulation","authors":"Haosen Wang,&nbsp;Wentao Xu,&nbsp;Xiaoheng Han","doi":"10.1140/epjp/s13360-025-06661-x","DOIUrl":"10.1140/epjp/s13360-025-06661-x","url":null,"abstract":"<div><p>In this study, the thermomechanical properties of a two-dimensional novel allotrope, the R12-graphene nanosheet, are characterized via nonequilibrium molecular dynamics simulations performed in LAMMPS, employing the AIREBO-M potential to capture both covalent and van der Waals interactions. Key properties, such as Young’s modulus, toughness, and thermal conductivity (TC) coefficient, are examined. The influence of critical parameters, including side lengths, temperature, vacancy defects, and the number of layers, on these thermomechanical properties is systematically analyzed. Based on stress–strain curve analysis, the small variations in elastic modulus, toughness, and TC between armchair and zigzag configurations suggest that R12-graphene nanosheets exhibit nearly isotropic behavior in both mechanical and thermal properties. Toughness is the most sensitive property of R12-graphene nanosheets to dimension, temperature, defects, and layer number, while TC and elastic modulus exhibit moderate to lower sensitivity. Compared to pristine hexagonal graphene, which exhibits a Young’s modulus of ≈1 TPa and in-plane TC of 3000–5000 W m⁻¹ K⁻¹, R12-graphene nanosheets display markedly lower elastic moduli (265–326 GPa) and TC (9.8–11.9 W m⁻¹ K⁻¹) over the 50–150 Å size range.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858575","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":"A Kohonen network approach to phase transition detection","authors":"Rosario Pullano","doi":"10.1140/epjp/s13360-025-06714-1","DOIUrl":"10.1140/epjp/s13360-025-06714-1","url":null,"abstract":"<div><p>We present a unified, unsupervised approach based on self-organizing maps for the detection and characterization of phase transitions across a variety of classical spin models. By training a 15 × 15 SOM on equilibrium configurations generated via Metropolis sampling, we define a “neural activity” metric R(T) as the fraction of neurons that respond to at least one input at temperature T. Scanning R(T) over a broad temperature range for the Ising, Blume–Capel, Potts, Heisenberg and XY models, we recover both continuous and discontinuous transitions as pronounced peaks or jumps in neural activity. We further demonstrate the robustness of R(T) under additive and flip-type noise, and extend the methodology to non-equilibrium quench dynamics by monitoring R(t) following an instantaneous cooling of the 2D Ising lattice. In all cases, SOM activity faithfully signals critical behavior and topological changes without requiring prior knowledge of the order parameter.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858572","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":"Lateral Goos–Hänchen shift in reflection and transmission via superposed super-Gaussian beams","authors":"Umer Wahid,&nbsp;Yao Peijun,&nbsp;Xu Lixin","doi":"10.1140/epjp/s13360-025-06710-5","DOIUrl":"10.1140/epjp/s13360-025-06710-5","url":null,"abstract":"<div><p>The lateral Goos–Hänchen (GH) shift in the reflection and transmission of super-Gaussian light beams interacting with a cavity containing a four-level sodium atomic medium is investigated. The analysis demonstrates that the GH shift and the spatial characteristics of the reflected and transmitted super-Gaussian pulses can be precisely controlled by manipulating the parameters of the incident light beams. A complementary relationship between the reflection and transmission spectra is observed, highlighting the interdependence of these phenomena. Furthermore, the spatial intensity profiles of the transmitted and reflected beams, along with their corresponding GH shifts, exhibit significant modulation patterns near the origin in the <span>(x)</span>-<span>(y)</span> plane. These modulations result in beam shapes that transition between circular and elliptical geometries, with variations ranging from sharply defined to substantially broadened forms. The findings provide valuable insights for the development of advanced optical systems and precision sensing applications, paving the way for innovative uses of beam shaping and GH shift phenomena.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858574","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":"(V_{cb}) puzzle in semi-leptonic (Brightarrow D^*) decays revisited","authors":"Shuang-Yi Li,&nbsp;Jie Xu,&nbsp;Rui-Xiang Shi,&nbsp;Li-Sheng Geng,&nbsp;Yi Zhang","doi":"10.1140/epjc/s10052-025-14599-8","DOIUrl":"10.1140/epjc/s10052-025-14599-8","url":null,"abstract":"<div><p>Inspired by the newly reported <span>(Brightarrow D^*(rightarrow Dpi )ell bar{nu }_ell )</span> differential decay rates by the Belle and Belle II Collaborations, we revisit the <span>(V_{cb})</span> puzzle in semi-leptonic <span>(Brightarrow D^*)</span> decays, considering the latest lattice QCD (LQCD) simulations and light-cone sum rule (LCSR) results. We examine the commonly used Caprini–Lellouch–Neubert (CLN), Boyd–Grinstein–Lebed (BGL), and heavy quark effective theory (HQET) parameterizations. We demonstrate that these three parameterizations yield consistent results and reconfirm the <span>(V_{cb})</span> puzzle. Then, we use a state-of-the-art Bayesian method to estimate the impact of higher-order terms beyond the present HQET expansion on the uncertainty of <span>(V_{cb}.)</span> We show that higher-order effects cannot eliminate the deviation between the exclusive and inclusive determinations of <span>(V_{cb}.)</span> Finally, utilizing the best-fit results obtained in the HQET parameterization via fitting LQCD and LCSR data only as inputs, we predict the relevant observables, i.e., <span>(R_{D^*},)</span> <span>(F_L^{D^*},)</span> and <span>(P_tau ^{D^*},)</span> sensitive to new physics in the <span>(Brightarrow D^*ell bar{nu }_ell )</span> decays. We conclude that lepton-flavour universality violations still exist in the <span>(brightarrow ctau nu )</span> transitions.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 8","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14599-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858571","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":"Braneworld neutron stars: constraining brane tension with observational data","authors":"Masum Murshid,&nbsp;Eman M. Moneer,&nbsp;Euaggelos E. Zotos,&nbsp;Nilofar Rahman,&nbsp;Mehedi Kalam","doi":"10.1140/epjc/s10052-025-14561-8","DOIUrl":"10.1140/epjc/s10052-025-14561-8","url":null,"abstract":"<div><p>In this article, we investigate the properties of neutron stars within the braneworld model, employing six distinct piece-wise polytropic equation of states. These equation of states satisfy observational constraints put by GW170817 event and pulsar observations (PSR J0740 and PSR J0030) within general relativity framework. Our primary goal is to assess whether these equation of states, in conjunction with the braneworld framework, can accommodate more massive neutron stars, as suggested by the GW190814 observation, while remaining consistent with established observational constraints. The brane tension parameter significantly affects the mass-radius and mass-tidal deformability relations, particularly for neutron stars with masses exceeding the canonical value. We establish strong constraints on the brane tension by comparing the canonical neutron star radius and tidal deformability with the results from the braneworld model, a stringent lower bound on the brane tension, <span>(lambda &gt; 2 times 10^{37} , text{ dyne/cm } ^2 )</span>. Our results demonstrate that the braneworld model allows for the existence of neutron stars with masses greater than those predicted by General Relativity, in agreement with the GW190814 observation, and highlight the significant role of brane tension in shaping the properties of neutron stars.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 8","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14561-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144853653","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":"Investigation of UV-Femtosecond laser ablation on metallic substrates","authors":"Benedikt Buchner,&nbsp;Steffen Mittelmann,&nbsp;Udo von Toussaint,&nbsp;Rudolf Neu","doi":"10.1007/s00339-025-08811-5","DOIUrl":"10.1007/s00339-025-08811-5","url":null,"abstract":"<div><p>Pulsed laser ablation is a common method for the analysis of material composition in solid materials. The use of femtosecond lasers allows for high depth resolution due to the low heat transfer into the material in metallic substrates. For such investigations, a sound knowledge of the ablation characteristics of the material is necessary. In this study, we present ablation thresholds and rates in a vacuum environment for tungsten, EUROFER 97, aluminum, copper, and bismuth using a laser setup capable of producing 400 fs, 343 nm pulses with a maximum intensity of <span>(varvec{5cdot 10^{15}};text {W},text {cm}^{-2})</span>. We find ablation thresholds of 530 <span>(text {mJ},text {cm}^{-2})</span>, 200 <span>(text {mJ},text {cm}^{-2})</span>, 370 <span>(text {mJ},text {cm}^{-2})</span>, 360 <span>(text {mJ},text {cm}^{-2})</span> and 140 <span>(text {mJ},text {cm}^{-2})</span> for the materials, respectively. We also find minimum ablation rates of about 10 nm in all materials, showing the possibility of ablation experiments with a depth resolution of this order. The experiments on bismuth show an unexpected ablation behavior, since the ablation leads to strongly molten crater surfaces. An influence of the ratio of optical and thermal penetration depth on the ablation characteristics can be determined. The ablation data obtained in this study allow material characterization with high depth resolution femtosecond laser experiments.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00339-025-08811-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum: Impact of loop quantum gravity on gravitational lensing, thermal fluctuations, tidal force and geodesic deviation around a black hole","authors":"Farzan Mushtaq,&nbsp;Xia Tiecheng,&nbsp;Faisal Javed,&nbsp;Allah Ditta,&nbsp;Bander Almutairi,&nbsp;G. Mustafa,&nbsp;Abdullo Hakimov","doi":"10.1140/epjc/s10052-025-14573-4","DOIUrl":"10.1140/epjc/s10052-025-14573-4","url":null,"abstract":"","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 8","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14573-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144853581","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":"Phase distribution analysis of high temperature emitting regions induced by CW laser irradiation in silica glass","authors":"Masataka Sato,&nbsp;Hirofumi Hidai,&nbsp;Sho Itoh,&nbsp;Souta Matsusaka","doi":"10.1007/s00339-025-08788-1","DOIUrl":"10.1007/s00339-025-08788-1","url":null,"abstract":"<div><p>The fiber fuse phenomenon refers to the propagation of an optical discharge characterized by high temperatures and high electron density in optical fibers. This phenomenon has been applied to the drilling of bulk silica glass. In this method, hole drilling is performed by controlling the void shape generated by the fiber fuse phenomenon. This study investigated the phase distribution in the continuous-wave (CW) laser-induced high-temperature emitting region, which is critical for clarifying the void formation mechanism in glass. High-speed observations were conducted to analyze the phase distributions. The observations revealed the following phase distribution: a gas-filled void surrounded by an emitting liquid. The void was unevenly distributed in the liquid phase. Considering the temperature distribution, this uneven void distribution was attributed to the flow of the liquid phase, driven by an imbalance in the interfacial tension between the void and the surrounding liquid. Furthermore, it was found that the void was deformed by generating a pressure difference between itself and its surroundings. In particular, the pressure difference between neighboring voids leads to void merging. These findings contribute to the formation of high-aspect holes, understanding the principles underlying fiber fuses, and analysis of high-temperature, high-density plasma behavior.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843251","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}