物理最新文献

{"title":"A perturbative approach to complexity during shearing, dissipative collapse","authors":"Kevin Reddy,&nbsp;Megan Govender","doi":"10.1140/epjc/s10052-025-13750-9","DOIUrl":"10.1140/epjc/s10052-025-13750-9","url":null,"abstract":"<div><p>We investigate the notion of complexity as defined by Herrera et al. (Phys Rev D 97:044010, 2018) for a star undergoing dissipative collapse in the presence of shear. We adopt a perturbative scheme which tracks the onset of collapse from an initially static configuration described by the Bowers–Liang model. The complexity for the initially static configuration is driven solely by the anisotropy and grows as the difference in the radial and tangential stresses grow. As the star loses equilibrium and transits into a dissipative collapse phase, the dynamical complexity is enhanced by contributions from the anisotropy and density inhomogeneity. The novelty of our work highlights the impact of pressure anisotropy and density inhomogeneity to the evolution of the complexity factor as a self-gravitating body evolves from an initially complexity-free and static regime into a dynamical radiating stellar object in the presence of shear.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-13750-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995512","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":"Theoretical analysis of two-neutron transfer in the (^{12})C(p,t)(^{10})C reaction","authors":"E. N. Cardozo,&nbsp;J. Lubian","doi":"10.1140/epja/s10050-024-01473-6","DOIUrl":"10.1140/epja/s10050-024-01473-6","url":null,"abstract":"<div><p>This work studies the two-neutron pickup transfer in the reaction <span>(^{12})</span>C(p,t)<span>(^{10})</span>C at 43 and 80 MeV in the laboratory frame. Finite-range coupled reaction channel calculations were performed to analyze the experimental angular distributions for direct and sequential two-neutron transfer mechanisms. Shell-model calculations were carried out to derive the spectroscopic amplitudes for the target overlaps. We show that the results of the both mechanisms present the same order of magnitude of the experimental data, thus there is a competition between the direct and sequential mechanisms for both energies studied. The data, in general, are well-described for the coherent sum of the direct and sequential transfers without any normalization factor.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995705","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":"Low-cost and high-performance N-type Mg3Sb1.5Bi0.5-based Thermoelectric materials for medium and low temperature applications via Zn and Se co-doping","authors":"Xin Yan,&nbsp;Huisong Zeng,&nbsp;Xueguo Liu,&nbsp;Xiaolan Zhang,&nbsp;Guocai Yuan,&nbsp;Tong Liu,&nbsp;Ruonan Min,&nbsp;Biyou Peng,&nbsp;Lihong Huang","doi":"10.1007/s00339-025-08255-x","DOIUrl":"10.1007/s00339-025-08255-x","url":null,"abstract":"<div><p>Improving the power factor is a crucial parameter in enhancing thermoelectric performance, making it essential to find an effective strategy for its enhancement. This study examines n-type Mg₃Sb_1.5Bi₀.5-based thermoelectric materials doped with Zn and Se. Se is added to adjust the carrier concentration, while Zn is introduced into Mg_3.2Sb_1.5Bi_0.49Se_0.01 to manipulate the carrier scattering mechanism. Experimental results indicate a significant increase in carrier mobility from 42.21 cm² V^− 1 s^− 1 to 73.92 cm² V^− 1 s^− 1, leading to a substantial enhancement in electrical conductivity and power factor across the entire temperature range under investigation. Additionally, due to reduced lattice thermal conductivity resulting from the introduction of efficient phonon scattering centers in the Zn and Se co-doped sample, Mg_3.18Zn_0.02Sb_1.5Bi_0.49Se_0.01 attains a maximum <i>ZT</i> value of 1.77 at 623 K, resulting in a notable average <i>ZT</i> ≈ 1.24 over the temperature range of 300 to 673 K. Given its cost-effectiveness and low toxicity, this material is anticipated to replace the commercially available n-type Bi₂Te₃-based thermoelectric materials commonly used at moderate and low temperatures.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995545","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":"BSNet: a boundary-aware medical image segmentation network","authors":"Honghao Jiang,&nbsp;Ling-Fang Li,&nbsp;Xue Yang,&nbsp;Xiaojun Wang,&nbsp;Ming-Xing Luo","doi":"10.1140/epjp/s13360-024-05960-z","DOIUrl":"10.1140/epjp/s13360-024-05960-z","url":null,"abstract":"<div><p>Accurate segmentation of medical images can provide foundations for clinical and disease diagnosis. Inaccurate segmentation boundaries often result from limited contextual information and insufficient discriminating feature maps after consecutive pooling and upsampling operations in most existing methods. In this paper, we present a novel boundary-aware medical image segmentation network (BSNet) for resolving the multi-objective segmentation problem. We exploit a backbone network to extract multi-scale feature representations and design an adaptive contrast boundary-aware module (ACB), which uses the method of combining nonlinear filters with deep learning to extract high-quality boundary maps. We then build a feature fusion (FF) module to fuse multi-scale features with boundary maps, providing decoder with rich multi-scale features enhanced with boundary information, and facilitating cross-channel interactions. To further enhance the uncertain regions of the boundaries, we utilize the boundary spatial enhancement (BSE) module to learn the feature map of boundary locations with the assistance of the Sobel operator. We conducted experiments with three challenging public datasets to evaluate the effectiveness of BSNet. Simulation results on various datasets show that the present model outperforms state-of-the-art segmentation methods, obtaining up to 2.73% improvement in Dice coefficient (DICE) score. BSNet opens new ways of designing better boundary-aware segmentation network.Please confirm the corresponding author is correctly identified.No problem.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995729","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":"The Palatini formalism of the (f(R,{mathcal {L}}_{m},T)) theory of gravity","authors":"J. G. de Lima Jr.,&nbsp;P. H. R. S. Moraes,&nbsp;E. Brito,&nbsp;J. A. S. Fortunato","doi":"10.1140/epjc/s10052-024-13731-4","DOIUrl":"10.1140/epjc/s10052-024-13731-4","url":null,"abstract":"<div><p>We present the first formulation of the recently proposed <span>(f(R,{mathcal {L}}_m,T))</span> theory of gravity within the Palatini formalism, a well-known alternative variational approach where the metric and connection are treated as independent variables. By applying this formalism, we derive a new set of field equations that exhibit, as expected, distinct properties compared to their metric formalism counterparts. We particularly present the Newtonian limit of this formalism, as well as the resulting Friedmann-like equations. We highlight that potential observational signatures may distinguish between the metric and Palatini frameworks. Our results open new pathways for exploring the phenomenology of modified gravity theories and their testability with observational data.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13731-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994903","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":"Enhanced circular dichroism induced by connectivity effect of rectangular metal nanorods","authors":"Hang Zhang,&nbsp;Zhongtao Liu,&nbsp;Lei Liu,&nbsp;Hui Li","doi":"10.1140/epjd/s10053-024-00943-2","DOIUrl":"10.1140/epjd/s10053-024-00943-2","url":null,"abstract":"<p>Compared to natural chiral structures, planar chiral plasmonic nanostructures, which are two-dimensional artificial structures composed of noble metals that break mirror symmetry, are widely applied in fields such as analytical chemistry, pharmaceutical production, and bioanalytical monitoring. Understanding circular dichroism (CD) and its enhancement mechanisms is crucial for these applications. Although a variety of chiral structures have been extensively studied, a deep understanding of the tunability of the CD effect remains insufficient. In particular, helical structures face challenges such as difficult fabrication and poor tunability. In this study, we designed a chiral structure composed of rectangular metal nanorods and metallic spheres, aiming to achieve a significant tunable CD effect by utilizing the connectivity effect of the metal nanorods, reaching an impressive CD value of 0.7. Results calculated by the finite element method show that, near the resonant wavelengths of 710 nm and 730 nm, the spectral responses of <span>({T}_{++})</span> and <span>({T}_{--})</span>, respectively, exhibit peak and valley patterns, thereby generating a substantial CD effect. Fundamentally, this is due to the shifting of the resonance modes at these specific wavelengths under RCP and LCP light. The extent of this shift can be precisely manipulated by altering the width of the rectangular metal nanorods, thus enabling controlled CD effects. Moreover, the CD effect is found to be highly dependent upon the geometric parameters of the designed structures. In summary, these findings contribute significantly to the development of planar chiral plasmonic nanostructures with tunable and large CD effects, providing valuable insights for their optimization and practical applications.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995558","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":"New models of quintessential inflation featuring plateau and hilltop potentials","authors":"Swagat S. Mishra,&nbsp;Varun Sahni","doi":"10.1140/epjc/s10052-025-13792-z","DOIUrl":"10.1140/epjc/s10052-025-13792-z","url":null,"abstract":"<div><p>We introduce a new class of hilltop and plateau potentials which can successfully unify inflation and dark energy resulting in quintessential inflation (QI). Interestingly these new potentials are related through an inverse transformation. Namely, if <span>(V(phi ) = V_0 , v(phi ))</span> is a plateau potential then the inverse potential <span>(V(phi ) = V_0 left[ v(phi )right] ^{-1})</span> describes hilltop QI. A simple example is provided by the KKLT-inspired potential <span>(v(phi ) = left[frac{M^{2n} + phi ^{2n}}{N^{2n} + phi ^{2n}}right],)</span>. When <span>(M/N ll 1)</span> this potential describes plateau QI, while its inverse, <span>(left[ v(phi )right] ^{-1})</span> describes hilltop QI. Other simple models of QI arise for the class of potentials <span>(V(phi ) sim exp left[mp f(phi )right])</span>, where the − (<span>(+)</span>) sign is associated with a plateau (hilltop). A key feature of this new class of QI models is the near absence of small dimensionless parameters, or small mass parameters (relative to the energy scale of the Standard Model of particle physics) – which are usually associated with the presence of dark energy. A forecast for the gravitational wave background generated in these models is provided.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-13792-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995393","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":"Dual quadratic compound multiswitching anti-synchronization of Lorenz, Rössler, Lü and Chen chaotic systems","authors":"Govind Singh,&nbsp;Dinesh Khattar,&nbsp;Neha Agrawal","doi":"10.1140/epjb/s10051-024-00855-5","DOIUrl":"10.1140/epjb/s10051-024-00855-5","url":null,"abstract":"<p>This paper offers a unique synchronization strategy for synchronizing eight chaotic systems. The new approach is referred to as dual quadratic compound anti synchronization. We additionally employed signal multi-switching to augment the complexity of the suggested technique. In communication theory, the transmission and security of the resulting signal are more effective because of the numerous combinations of chaotic systems and multiswitching that provide such complicated dynamic behavior. To demonstrate the acquired results, Lorenz, Rössler, Lü, and Chen chaotic system are used. Using the Lyapunov stability principle, sufficient conditions are attained and appropriate controllers are built to achieve the required synchronization between eight chaotic systems. To validate the findings from theory, numerical simulations, and graphics are presented using MATLAB.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995285","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":"Simulation of a liquid drop on a soft substrate","authors":"Yalda Poorhoshyar,&nbsp;Amir H. Fatollahi,&nbsp;Amir Aghamohammadi","doi":"10.1140/epje/s10189-024-00470-3","DOIUrl":"10.1140/epje/s10189-024-00470-3","url":null,"abstract":"<p>A liquid drop resting on a soft substrate is numerically simulated as an energy minimization problem. The elastic substrate is modeled as a cubic lattice of mass-springs, to which an energy term controlling the change of volume is associated. The interfacial energy between three phases of solid, liquid, and vapor is also introduced. Under the constant volume constraint of the liquid drop, the total energy of the system is subjected to a numerical minimization process by which profiles of both substrate and drop are obtained. The numerical simulation enables the modeling of the wetting setup with various parameters associated with solid and liquid phases, including the Young’s modulus and Poisson’s ratio of the solid, the surface tension of the three phases, and geometrical parameters such as the contact radius or thickness of the solid. The direct outputs of the minimization process are the displacements of the solid lattice and boundary points of the liquid, by which the behavior of all relevant quantities, such as contact angles in the three phases, as well as the effective surface tension of the solid, can be quantitatively studied. The resulting displacements of the solid are compared with the exact solution of the elasticity equation under the assumption of no tangential traction, and a quite satisfactory agreement is observed. However, at larger Young’s modulus or lower Poisson’s ratios the agreement between the numerical results and the analytical solutions is lost in the vicinity of the contact points. Interestingly, a non-zero tangential traction in the vicinity of contact points is calculated by the numerical outputs, indicating that the assumption of zero tangential traction is not valid generally around the contact points. The effective surface tension at the contact points is calculated for an incompressible solid substrate, showing a linear increase with respect to the Young’s modulus of the solid, as <span>(delta gamma =c,E)</span>.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995538","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":"A comparative study of magneto-capacitance with magneto-electric coupling and transport response of 0.5LaFeO3-0.5PbZr0.58Ti0.42O3 nanocomposite","authors":"Debajyoti Nath,&nbsp;Harsh Sharma,&nbsp;Rajib Mallik","doi":"10.1007/s00339-025-08267-7","DOIUrl":"10.1007/s00339-025-08267-7","url":null,"abstract":"<div><p>The effects of magnetic field on magnetoelectric coupling, dielectric and transport properties of 0.5LaFeO₃-0.5PbZr_0.58Ti_0.42O₃ nanocomposites are investigated at room temperature. The maximum value of magnetoelectric coupling is found to ~ 1.3 and ~ 0.2 mV/cm-Oe, which approves the multiferroic in nature, it may agree with the strain mediated piezomagnetic phase and magnetocapacitance property of the material. The observed magneto-capacitance (~ 23%) at lower frequency attributes to the interface or space charge polarization of sample as the Maxwell-Wagner effect. The classical electrodynamics effect is the main reason for the magnetoimpedance behaviour (~ 50%) at room temperature. The involvement of grain and grain boundaries effect may takes dominating role on conductivity, which is illustrated from the impedance and modulus diagrams assigned the non-Debye type phenomena. The relaxation frequency is changed by an application of magnetic field corroborating the spin dependent electrical transport mechanism at the grain boundaries. The decreasing nature of ac conductivity with applied magnetic field characterizes the presence of defect states in interfaces of LaFeO₃ and PbZr_0.58Ti_0.42O₃ grains. Also, it may agree to the occurance of strain mediation of piezomagnetic phase of the system. Also this composite may corresponds to the occurance of strain mediation of piezomagnetic phase and magnetodielectric effect.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995544","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}