The European Physical Journal Plus最新文献

{"title":"Deformation of the Heisenberg–Weyl algebra and the Lie superalgebra (mathfrak {osp}left( {1|2} right)): exact solution for the quantum harmonic oscillator with a position-dependent mass","authors":"E. I. Jafarov,&nbsp;S. M. Nagiyev,&nbsp;J. Van der Jeugt","doi":"10.1140/epjp/s13360-025-06113-6","DOIUrl":"10.1140/epjp/s13360-025-06113-6","url":null,"abstract":"<div><p>We propose a new deformation of the quantum harmonic oscillator Heisenberg–Weyl algebra with a parameter <span>(a&gt;-1)</span>. This parameter is introduced through the replacement of the homogeneous mass <span>(m_0)</span> in the definition of the momentum operator <span>(hat{p}_x)</span> as well as in the creation–annihilation operators <span>({hat{a}}^pm)</span> with a mass varying with position <i>x</i>. The realization of such a deformation is shown through the exact solution of the corresponding Schrödinger equation for the non-relativistic quantum harmonic oscillator within the canonical approach. The obtained analytical expression of the energy spectrum consists of an infinite number of equidistant levels, whereas the wavefunctions of the stationary states of the problem under construction are expressed through the Hermite polynomials. Then, the Heisenberg–Weyl algebra deformation is generalized to the case of the Lie superalgebra <span>(mathfrak {osp}left( {1|2} right))</span>. It is shown that the realization of such a generalized superalgebra can be performed for the parabose quantum harmonic oscillator problem, the mass of which possesses a behavior completely overlapping with the position-dependent mass of the canonically deformed harmonic oscillator problem. This problem is solved exactly for both even and odd stationary states. It is shown that the energy spectrum of the deformed parabose oscillator is still equidistant; however, both even- and odd-state wavefunctions are now expressed through the Laguerre polynomials. Some basic limit relations recovering the canonical harmonic oscillator with constant mass are also discussed briefly.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809115","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":"Integrability and analytic solutions for a damped variable-coefficient fifth-order modified Korteweg-de Vries equation for the surface waves in a strait or large channel","authors":"Hao-Dong Liu,&nbsp;Bo Tian,&nbsp;Chong-Dong Cheng,&nbsp;Tian-Yu Zhou,&nbsp;Xiao-Tian Gao,&nbsp;Hong-Wen Shan","doi":"10.1140/epjp/s13360-025-06101-w","DOIUrl":"10.1140/epjp/s13360-025-06101-w","url":null,"abstract":"<div><p>Investigations on the variable-coefficient nonlinear partial differential equations attract people's attention. In this paper, we investigate a damped variable-coefficient fifth-order modified Korteweg-de Vries equation for some fluids and cosmic plasmas. Under certain variable-coefficient constraints, we find that the equation is Painlevé integrable. By virtue of the real and complex simplified Hirota procedures, multiple real and complex soliton solutions are derived. Via the soliton wave ansatz method, we obtain some other analytic solutions such as the kink, bell, singular and periodic soliton solutions. Moreover, we discuss the influences of variable coefficients in the equation on those solitons graphically.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809124","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":"Black hole with global monopole charge in self-interacting Kalb-Ramond field","authors":"Mohsen Fathi,&nbsp;Ali Övgün","doi":"10.1140/epjp/s13360-025-06241-z","DOIUrl":"10.1140/epjp/s13360-025-06241-z","url":null,"abstract":"<div><p>In this study, we explore a static, spherically symmetric black hole solution in the context of a self-interacting Kalb-Ramond field coupled with a global monopole. By incorporating the effects of Lorentz-violating term <span>(ell)</span> and the monopole charge <span>(eta)</span> in the KR field, we derive the modified gravitational field equations and analyze the resulting black hole spacetime. The obtained solution exhibits deviations from the Schwarzschild metric with topological defect, as it is influenced by the monopole charge and self-interaction potential. We investigate the thermodynamic properties of the black hole, including its Hawking temperature, entropy, and specific heat, revealing novel stability conditions. Additionally, we perform solar system tests such as perihelion precession, gravitational redshift, light deflection, and time delay of signals to impose constraints on the Lorentz-violating parameter and monopole charge. Our findings suggest that these parameters have to be significantly small, although there are different constraints imposed by individual tests, ranging from <span>(10^{-9}le |ell |le 10^{-4})</span> and <span>(10^{-9}le eta le 10^{-6}, textrm{m}^{-1})</span>.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793179","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":"Influence of Vasyliunas-Cairns distributed non-thermal cold and hot electrons on the electron acoustic mode: a kinetic theory based exact numerical analysis","authors":"Muhammad Ahsan Shahzad,&nbsp; Aman-ur-Rehman,&nbsp;Muhammad Bilal,&nbsp;Nazish Rubab,&nbsp;Sadia Zaheer,&nbsp;Muhammad Sarfraz","doi":"10.1140/epjp/s13360-025-06213-3","DOIUrl":"10.1140/epjp/s13360-025-06213-3","url":null,"abstract":"<div><p>Numerous observations from spacecraft missions have revealed that the space plasmas can be best modeled through the incorporation of nonthermal distributions. In the contemporary analysis, we investigate electron-acoustic waves (EAWs) in nonthermal plasmas. These waves propagate as a result of temperature difference between two electron species, commonly referred to as hot (<span>(T_{h})</span>) and cold (<span>(T_{c})</span>) electrons with <span>(T_{h}&gt;T_{c})</span>. Both the hot and cold electrons are assumed to follow the Vasyliunas-Cairns distribution with considerations for limiting cases involving kappa and Maxwellian distributions. The Poison-Vlasov model is incorporated to calculate the longitudinal dielectric response function of electron-acoustic mode. Exact numerical analysis is performed to solve the dispersion relation equation which enables the calculation of dispersion and damping rate of electron-acoustic waves (EAWs). The influence of relevant parameters e.g., nonthermality parameters, the temperature ratio between hot and cold electrons, and the ratio of the number density of hot electrons to the total electrons is examined on the real and imaginary frequencies of the mode. In view of global modeling of naturally occurring space plasmas, this investigation contributes well to the understanding of heliospheric plasmas e.g., solar wind and magnetosphere.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793180","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":"Enhancing the thermoelectric performance of Janus MoSSe monolayer via pressure","authors":"Anisha,&nbsp;Ramesh Kumar,&nbsp;Mukhtiyar Singh,&nbsp;Sunita Srivastava,&nbsp;Tankeshwar Kumar","doi":"10.1140/epjp/s13360-025-06180-9","DOIUrl":"10.1140/epjp/s13360-025-06180-9","url":null,"abstract":"<div><p>By combining first-principles computations with the semi-classical Boltzmann transport equations, a systematic investigation of the structural, electronic and thermoelectric properties of the MoSSe Janus monolayer is conducted under pressure. The monolayer semiconducting nature is indicated by the band gap value (<i>E</i>_g = 1.5 eV), which may be further tuned from 0.56 to 1.67 eV by applying pressure in the -3GPa to + 2GPa range. The figure of merit (ZT) for p (n)-type carriers at 300 K in the absence of pressure is computed to be 0.67 and 0.59. The power factor has enhanced from 16.59 (27.21) Wm⁻¹ K⁻² to 227.15 (159.50) Wm⁻¹ K⁻² for <i>n</i> (<i>p</i>)-type carriers by applying an external pressure of -1 GPa to the Janus monolayer. For <i>n</i> (<i>p</i>) -type doping at 300 K, the corresponding maximum value of ZT is 0.82 (0.78), which is 39% (14%) greater for <i>n</i> (<i>p</i>) type than for pure MoSSe Janus monolayer. When the pressure is increased to + 3 GPa, the value of ZT for n-type doping is further increased to 0.73, which is 24% higher than the value for pure monolayer. It is possible for a pure Janus monolayer to undergo n-type doping under pressure due to the shifting of the conduction band minima and valence band maxima. This study presents an attractive approach for manipulating the material thermoelectric properties through external pressure application.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793177","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-Hermitian electron–positron annihilation under thermal effects","authors":"D. S. Cabral,&nbsp;A. F. Santos,&nbsp;R. Bufalo,&nbsp;N. B. Xavier","doi":"10.1140/epjp/s13360-025-06229-9","DOIUrl":"10.1140/epjp/s13360-025-06229-9","url":null,"abstract":"<div><p>In this paper we examine the thermal effects into the <span>(e^{+}e^{-}rightarrow ell ^{+}ell ^{-})</span> scattering in a non-Hermitian extension of QED. We compute the thermal contributions to this scattering cross section within the Thermo Field Dynamics approach. In order to highlight the non-Hermitian effects we have considered some limits of interest: i) zero-temperature limit and high-energy limit and ii) high-temperature regime. Since this type of scattering possesses accurate experimental data for the cross section (for muon and tau at the final state) it can be used to set stringent bounds upon the non-Hermitian parameters.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793178","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":"Vector solitons and breathers for a variable-coefficient coherent coupled nonlinear Schrödinger equation","authors":"Lin-Wang Zhu,&nbsp;Cui-Cui Ding","doi":"10.1140/epjp/s13360-025-06215-1","DOIUrl":"10.1140/epjp/s13360-025-06215-1","url":null,"abstract":"<div><p>In this paper, the variable-coefficient coherent coupled nonlinear Schrödinger system in weak birefringent fibers is investigated analytically. Lax pair and the <i>N</i>-fold potential transformation for the system are constructed. For the complex envelope of two interacting optical modes, exact vector one and two solitons and breathers are derived from the obtained potential transformation. Solitons and breathers with different dynamic properties are explored via adjusting the coefficient of the self-phase modulation and cross-phase modulation. Asymptotic analysis is used to discuss the interactions between two solitons. Two kinds of breathers with their existing conditions are analyzed.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793176","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":"Generalized Runcorn’s theorem and crustal magnetism","authors":"Ivica Smolić","doi":"10.1140/epjp/s13360-025-06228-w","DOIUrl":"10.1140/epjp/s13360-025-06228-w","url":null,"abstract":"<div><p>During the era of NASA’s Apollo missions, Keith S. Runcorn proposed an explanation of discrepancy between the Moon’s negligible global magnetic field and magnetized samples of lunar regolith, based on identical vanishing of external magnetic field of a spherical shell, magnetized by an internal source which is no longer present. We revisit and generalize the Runcorn’s result, showing that it is a consequence of a (weighted) orthogonality of gradients of harmonic functions on a spherical shell in arbitrary number of dimensions. Furthermore, we explore bounds on external magnetic field in the case when the idealized spherical shell is replaced with a more realistic geometric shape and when the thermoremanent magnetization susceptibility deviates from the spherical symmetry. Finally, we analyse a model of thermoremanent magnetization acquired by crustal inward cooling of a spherical astrophysical body and put some general bounds on the associated magnetic field.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793166","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":"Damage characteristics of TC4 flyer obliquely penetrating CF/BMI laminates under high temperature environment","authors":"Chuang Chen,&nbsp;Shaohua Zhou,&nbsp;Zihan Guo,&nbsp;Enling Tang","doi":"10.1140/epjp/s13360-025-06226-y","DOIUrl":"10.1140/epjp/s13360-025-06226-y","url":null,"abstract":"<div><p>In response to the urgent need for high-temperature-resistant, impact-resistant resin-based composites for the fan containment case of high thrust-to-weight ratio turbofan engines, numerical simulations were conducted for the oblique penetration of Ti- 6 Al- 4 V (TC4) flyers into CF/BMI laminates at different temperatures (200 °C and 300 °C) and variable yaw and pitch angles (0°, 10°, 20°, 30°, and 40°). A mesoscale model was established, considering the material laminate structure and surface weaving structure. The accuracy of the numerical simulation method was validated through experiments. The impact of different incident angles on the failure modes and energy absorption characteristics of the composite laminates at high temperatures were analyzed. The results indicate that, in terms of failure modes, under oblique penetration conditions, the failure modes of the laminate primarily include laminate cracking, shear plugging, fiber tensile fracture, and resin cracking. When the yaw angle is larger, local stresses cause cracking on the back of the target, mainly due to local shear plugging. When the pitch angle is larger, the laminate bending deformation is concentrated locally, and the overall deformation of the laminate is minimal. Shear and tensile failure occur between the fibers and resin matrix, causing the flyer to detach. The fibers on the upper side of the flyer experience deflection. As the temperature increases, the performance of the matrix is observed to decline, leading to thermal stress mismatch between the fibers and the matrix. Plastic deformation of the matrix occurs, resulting in a weakening of the interfacial bonding strength between the fibers and the matrix. Fiber bundles are found to fracture, and the phenomenon of interfacial debonding becomes more pronounced. In terms of energy absorption characteristics, as the yaw angle increases, the flyer is observed to consume more kinetic energy, and the strain energy and frictional dissipation energy of the laminate also increase. Under large-angle oblique penetration conditions, the laminate exhibits stronger impact resistance. As the pitch angle increases, the laminate kinetic energy absorption time is extended, frictional dissipation energy increases, the time for the flyer to penetrate the target is prolonged, and the remaining kinetic energy decreases. An increase in temperature leads to a reduction in the impact resistance of the laminate.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143786580","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":"Combining finite volume method and physics-informed neural networks for parameter identification and model selection in cell invasion models","authors":"Mahya Pashapour,&nbsp;Mostafa Abbaszadeh,&nbsp;Mehdi Dehghan","doi":"10.1140/epjp/s13360-025-06220-4","DOIUrl":"10.1140/epjp/s13360-025-06220-4","url":null,"abstract":"<div><p>Accurate modeling of a phenomenon is essential for enhancing predictive capabilities and understanding its underlying mechanisms. The precision of model predictions is heavily influenced by the parameters of the model. Consequently, in addition to addressing problems framed as Partial Differential Equations or Ordinary Differential Equations, parameter estimation is crucial for improving solution accuracy and selecting the optimal model among alternatives. This study focuses on estimating the parameters of the Fisher-KPP (Ronald Fisher, Andrey Kolmogorov, Ivan Petrovsky, Nikolai Piskunov) model using physics-informed neural networks. The Fisher-KPP reaction–diffusion model, which explores cell invasion, has four variants depending on whether the parameters are free or fixed. We employ the finite volume method to simulate the model and obtain numerical solutions.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778020","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}