The European Physical Journal Plus最新文献

{"title":"Probing wormholes supported by Casimir energy in noncommutative and GUP-corrected spacetimes","authors":"Lavish Kumar Aidasani,&nbsp;Hamdan Ahmad","doi":"10.1140/epjp/s13360-025-06127-0","DOIUrl":"10.1140/epjp/s13360-025-06127-0","url":null,"abstract":"<div><p>We explore the effects of noncommutativity and generalized uncertainty principles (GUP) on the Casimir wormhole spacetime. Building on the work of Jusufi (Eur. Phys. J. C 80:127, 2020), we examine three specific GUP models: the Kempf, Mangano, and Mann (KMM) model; the Detournay, Gabriel, and Spindel (DGS) model; and the Type II model. Our study focuses on how corrections to the Casimir energy density, influenced by the presence of a minimal length <span>(x_0 = hbar sqrt{theta })</span>, impact wormhole dynamics. We compare results from these models to the ones based on the noncommutative coherent state approach at higher orders of perturbation in <span>(sqrt{theta })</span>. Specifically, we derive expressions for the shape function, light deflection angle in the weak deflection limit, ADM mass of the wormhole, and equation of state parameters. We also evaluate the null, weak, and strong energy conditions to assess the traversability of Casimir wormholes. Our primary contribution lies in incorporating the noncommutative model into the analysis and extending the modifications in Casimir energies to the sixth order.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481241","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 gap between two approaches of dimensional reduction for a six-dimensional Kaluza–Klein theory","authors":"Tuan Q. Do,&nbsp;W. F. Kao","doi":"10.1140/epjp/s13360-025-06080-y","DOIUrl":"10.1140/epjp/s13360-025-06080-y","url":null,"abstract":"<div><p>Inspired by the five-dimensional Kaluza–Klein theory, we would like to study the dimensional reduction issue of six-dimensional Kaluza–Klein extension in this paper. In particular, we will examine two possible approaches of dimensional reduction from six-dimensional spacetimes to four-dimensional ones. The first one is a direct dimensional reduction, i.e., from six-dimensional spacetimes directly to four-dimensional ones, via a <span>(T^2equiv S^1 times S^1)</span> compactification; while, the second one is an indirect dimensional reduction, i.e., from six-dimensional spacetimes to five-dimensional ones then four-dimensional ones, via two separated <span>(S^1)</span> compactifications. Interestingly, we show that these two approaches lead to different four-dimensional effective actions although using the same six-dimensional metric. It could therefore address an important question of which approach is more reliable than the other.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465954","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":"Constructing multipartite planar maximally entangled states from phase states and quantum secret sharing protocol","authors":"L. Bouhouch,&nbsp;Y. Dakir,&nbsp;A. Slaoui,&nbsp;R. Ahl Laamara","doi":"10.1140/epjp/s13360-025-06118-1","DOIUrl":"10.1140/epjp/s13360-025-06118-1","url":null,"abstract":"<div><p>In this paper, we explore the construction of planar maximally entangled (PME) states from phase states. PME states form a class of <i>n</i>-partite states in which any subset of adjacent particles whose size is less than or equal to half the total number of particles is in a fully entangled state. This property is essential to ensuring the robustness and stability of PME states in various quantum information applications. We introduce phase states for a set of so-called noninteracting <i>n</i> particles and describe their corresponding separable density matrices. These phase states, although individually separable, serve as a starting point for the generation of entangled states when subjected to unitary dynamics. Using this method, we suggest a way to make complex multi-qubit states by watching how unconnected phase states change over time with a certain unitary interaction operator. In addition, we show how to derive PME states from these intricate phase states for two-, three-, four-, and K-qubit systems. This construction method for PME states represents a significant advance over absolutely maximally entangled (AME) states, as it provides a more accessible and versatile resource for quantum information processing. Not only does it enable the creation of a broader class of multipartite entangled states, overcoming the limitations of AME states, notably their restricted availability in low-dimensional systems; for example, in the absence of a four-qubit AME state, it also offers a systematic construction method for any even number of qudits, paving the way for practical applications in key quantum technologies such as teleportation, secret sharing, and error correction, where multipartite entanglement plays a central role in protocol efficiency.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471965","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":"Dynamics and optimal control of an extended SIQR model with protected human class and public awareness","authors":"Fahad Al Basir,&nbsp;Kottakkaran Sooppy Nisar,&nbsp;Ibraheem M. Alsulami,&nbsp;Amar Nath Chatterjee","doi":"10.1140/epjp/s13360-025-06108-3","DOIUrl":"10.1140/epjp/s13360-025-06108-3","url":null,"abstract":"<div><p>In this article, we have developed the SIQR type mathematical model including the protected human population and public awareness in the model for the dynamics of an epidemic outbreak. The “level of awareness”, due to awareness campaign, is taken as a separate model variable. Both local (information sharing from local area, relatives) and global awareness (information sharing from social media, Radio, TV, etc.) can increase the level of awareness. We have also included the impact of treatment for recovery from the infection. Also, we have assumed infection transmission as a decreasing function of media awareness. The existence of equilibria of the model and their stability nature have been studied with qualitative theory. The disease-free equilibrium is stable when <span>({mathcal {R}}_0&lt;1)</span> and unstable when <span>({mathcal {R}}_0&lt;1)</span>. A unique endemic equilibrium exists when <span>({mathcal {R}}_0&gt;1)</span>, and it shows a Hopf bifurcation if the infection rate crosses its critical value. The unstable endemic system becomes stable when the global awareness rate is increased. To obtain crucial insights into disease management strategies, sensitivity analysis is performed to examine the link between model parameters and the basic reproduction number <span>({mathcal {R}}_{0})</span>. Finally, we formulate an optimal control problem including three control parameters and solved using Pontryagin’s maximum principle. Numerical simulations are executed on the basis of analytical results. The regions of stability of the disease-free equilibrium are identified in different parameter planes. We have determined the optimal profiles of the three control functions to make the disease management process economically viable. This study concluded that the transmission dynamics of the pandemic depend on the rate of infection, the rate of global awareness, and the rate of awareness-based treatments. The proposed awareness-induced mathematical model that includes an optimal control approach is applicable to cost-effectively manage an epidemic outbreak.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471967","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":"Role of awareness programs on diabetes prevention and control of viral infection: a study of optimal control","authors":"Kalyan Kumar Pal,&nbsp;Rajanish Kumar Rai,&nbsp;Pankaj Kumar Tiwari,&nbsp;Arvind Kumar Misra","doi":"10.1140/epjp/s13360-025-06063-z","DOIUrl":"10.1140/epjp/s13360-025-06063-z","url":null,"abstract":"<div><p>Diabetes is a chronic metabolic disorder characterized by elevated blood glucose levels due to insufficient insulin production or ineffective use of insulin. While primarily driven by genetics and lifestyle, viral infections like enteroviruses, cytomegalovirus, hepatitis C, HIV, and COVID-19 have also been linked to triggering both type 1 and type 2 diabetes (T2D), possibly through immune system-induced metabolic changes. In this study, we propose and analyze a nonlinear mathematical model to investigate the effects of awareness campaigns on diabetes prevention and control of viral infection. We assume that individuals who are initially unaware of diabetes risk factors become informed through word-of-mouth communication, and adopt preventive behaviors. The model also includes the impact of social media and television advertisements in raising public awareness. We derive the basic reproduction number <span>((mathcal {R}_0))</span> for the system, which serves as a threshold parameter. Our analysis indicates that the system experiences a transcritical bifurcation as <span>(mathcal {R}_0)</span> crosses the unit value, indicating a shift in the stability of equilibria, and the potential for diabetes control. Additionally, we conduct a sensitivity analysis to identify the most influential parameters impacting the number of infected cases. The model is further expanded to incorporate two control strategies aimed at reducing the prevalence of both diabetic and at-risk individuals. Pontryagin’s Maximum principle, along with the forward-backward sweep method, is employed to solve the optimal control problem. Our findings evoke that interventions involving social media and television advertisements are more effective in promoting awareness and reducing the spread of diabetes risk compared to word-of-mouth communication alone.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471966","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":"Emergence of self-sustaining states in the two-population neural field model triggered by a comprehensive external input","authors":"Zeeshan Afzal,&nbsp;M. Yousaf,&nbsp;Naima Amin,&nbsp;M. Younas,&nbsp;M. Tayyab,&nbsp;M. Faisal Yasin","doi":"10.1140/epjp/s13360-025-06072-y","DOIUrl":"10.1140/epjp/s13360-025-06072-y","url":null,"abstract":"<div><p>In this work, a two-population neural field (TPNF) model is investigated under the influence of a more comprehensive spatiotemporal external input. The symmetric and stationary solutions (bump solutions) of the TPNF model serve as persistent activity states (working memory) in the brain. The emergence of these persistent activities in TPNF model is investigated under the influence of external inputs with an emphasis on temoral evolution. Earlier studies have used triangular and smooth alpha-type spatiotemporal external inputs, derived from experimental observations to study the emergence of bump solutions. In this work, we formulated a more comprehensive spatiotemporal external input (piecewise) that retains the characteristics of earlier inputs with some additional features that makes it more comprehensive. It is found that relative inhibition time constant <span>(tau)</span> is very significant in shaping the emergence of self-sustained activity states. Specific phases of the external input play crucial role for evoking these network activity states, e.g., total duration, amplitude, stimulus onset and peak time duration of the external input. It is discovered that the minimal amplitude and active duration to evoke network activity are lower than those found in earlier studies. The results in this work are computed numerically using RK-4 method.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465968","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":"Materiality of antimony doping in Ge–S amorphous chalcogenides in nonlinear switching","authors":"Anjani Kumar,&nbsp;S. Shukla,&nbsp;S. Kumar,&nbsp;Rajeev Gupta","doi":"10.1140/epjp/s13360-025-06088-4","DOIUrl":"10.1140/epjp/s13360-025-06088-4","url":null,"abstract":"<div><p>Optical transmissions are involved in the Ge₂₅S_75−xSb_x (<i>x</i> = 0, 10) chalcogenides thin films within the range of wavelength 300 to 3100 nm. Swanepoel’s approach is used for evaluation of linear optical parameters (n, k, x, <i>ε</i>ʹ and <i>ε</i>ʺ) on the basis of transmission measurements. Optical band gap (2.49 and 1.89 eV) and dispersion analysis are done by using Tauc’s and WDD relations, respectively. In search of the possibility of nonlinear switching in Ge₂₅S_75−xSb_x (<i>x</i> = 0, 10) chalcogenides, nonlinear index of refractions (1.456 × 10⁻¹² esu and 2.153 × 10⁻¹² esu) and nonlinear susceptibility (4.55 × 10⁻¹³ and 7.01 × 10⁻¹³) are also evaluated. Based on result out comes on the basis of figure of merit, the applicability for photonics is discussed.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465969","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":"Vacuum polarization effects of pointlike impurity","authors":"Yuri V. Grats,&nbsp;Pavel Spirin","doi":"10.1140/epjp/s13360-025-06096-4","DOIUrl":"10.1140/epjp/s13360-025-06096-4","url":null,"abstract":"<div><p>We develop precise formulation for the effects of vacuum polarization near a pointlike source with a zero-range (<span>(delta)</span>-like) potential in three spatial dimensions. There are different ways of introducing <span>(delta)</span>-interaction in the framework of quantum theory. We discuss the approach based on the concept of self-adjoint extensions of densely defined symmetric operators. Within this approach, we consider the real massive scalar field in three-dimensional Euclidean space with a single extracted point. Appropriate boundary conditions, imposed at this point, enable one to consider all self-adjoint extensions of <span>(- Delta)</span> as operators which can describe a pointlike source with a zero-range potential. In this framework, we compute the renormalized vacuum expectation value of the field square <span>(langle phi ^{{hspace{1.0pt}}2}(x)rangle _{textrm{ren}})</span> and the renormalized vacuum average of the scalar-field’s energy-momentum tensor <span>(langle T_{mu nu }(x)rangle _{textrm{ren}})</span>. Asymptotic cases are discussed in detail.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465967","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":"Horizon quantum mechanics for coherent quantum black holes","authors":"Wenbin Feng,&nbsp;Andrea Giusti,&nbsp;Roberto Casadio","doi":"10.1140/epjp/s13360-025-06065-x","DOIUrl":"10.1140/epjp/s13360-025-06065-x","url":null,"abstract":"<div><p>The formalism of the horizon quantum mechanics is applied to electrically neutral and spherically symmetric black hole geometries emerging from coherent quantum states of gravity to compute the probability that the matter source is inside the horizon. We find that quantum corrections to the classical horizon radius become significant if the matter core has a size comparable to the Compton length of the constituents, and the system is indeed a black hole with probability very close to one unless the core radius is close to the (classical) gravitational radius.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06065-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455679","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":"Demkov–Fradkin tensor for curved harmonic oscillators","authors":"Şengül Kuru,&nbsp;Javier Negro,&nbsp;Sergio Salamanca","doi":"10.1140/epjp/s13360-025-06067-9","DOIUrl":"10.1140/epjp/s13360-025-06067-9","url":null,"abstract":"<div><p>In this work, we obtain the Demkov–Fradkin tensor of symmetries for the quantum curved harmonic oscillator in a space with constant curvature given by a parameter <span>(kappa)</span>. In order to construct this tensor, we have firstly found a set of basic operators which satisfy the following conditions: (i) Their products give symmetries of the problem; in fact, the Hamiltonian is a combination of such products; (ii) they generate the space of eigenfunctions as well as the eigenvalues in an algebraic way; (iii) in the limit of zero curvature, they come into the well-known creation/annihilation operators of the flat oscillator. The appropriate products of such basic operators will produce the curved Demkov–Fradkin tensor. However, these basic operators do not satisfy Heisenberg commutators but close another Lie algebra which depends on <span>(kappa)</span>. As a by-product, the classical Demkov–Fradkin tensor for the classical curved harmonic oscillator has been obtained by the same method. The case of two dimensions has been worked out in detail: Here, the operators close a <span>(so_kappa (4))</span> Lie algebra; the spectrum and eigenfunctions are explicitly solved in an algebraic way and in the classical case the trajectories have been computed.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 2","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455680","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}