物理最新文献

{"title":"Anisotropic compact star: various equations of state","authors":"Rinkal Patel,&nbsp;B S Ratanpal","doi":"10.1007/s12043-025-02918-3","DOIUrl":"10.1007/s12043-025-02918-3","url":null,"abstract":"<div><p>We develop models of compact stars with pressure anisotropy on Finch–Skea space–time by applying a generalised equation of state (EoS), which includes specific cases such as linear, quadratic, polytropic, Chaplygin, and colour-flavour-locked (CFL) equations of state. The physical viability of these models is tested for the strange star candidate 4U 1820-30, with a mass <span>( M = 1.58M_odot )</span> and radius <span>(R = 9.1)</span> km. All models are found to be physically plausible.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073785","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":"Higgs decay to (Zgamma ) in the minimal supersymmetric standard model and its nonholomorphic extension","authors":"S. Israr,&nbsp;M. Rehman","doi":"10.1140/epjp/s13360-025-06401-1","DOIUrl":"10.1140/epjp/s13360-025-06401-1","url":null,"abstract":"<div><p>Recent measurements of <span>( h rightarrow Z gamma )</span> from CMS and ATLAS indicate an excess over standard model (SM) predictions, suggesting the presence of new physics. In this work, we investigate the <span>( h rightarrow Z gamma )</span> decay within the minimal supersymmetric standard model (MSSM) and its nonholomorphic extension, the NHSSM. Calculations are performed using the <i>FeynArts</i>/<i>FormCalc</i> setup, utilizing the pre-existing model file for MSSM and generating the NHSSM model file with the support of <span>SARAH</span>. For the parameter space examined in this study, MSSM contributions to <span>( h rightarrow Z gamma )</span> can significantly surpass SM predictions reaching to the value <span>(Gamma (h rightarrow Z gamma )= 9.77 times 10^{-6} ,, textrm{GeV})</span>, thereby bringing <span>( Gamma (h rightarrow Z gamma ) )</span> closer to the experimental value. The SM-predicted value deviates from the experimental value by <span>(1.7 sigma )</span>. However, the MSSM contributions can reduce this deviation to less than <span>(1 sigma )</span>. In contrast, NHSSM contributions remain negligible and do not produce sizable corrections to the <span>( h rightarrow Z gamma )</span> decay width.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073700","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":"Modeling the effects of psychological fear, media-induced awareness, and sanitation efforts on the dynamics of bacterial diseases","authors":"Kuldeep Kumar Tripathi,&nbsp;Maitri Verma,&nbsp;Arvind Kumar Misra","doi":"10.1140/epjp/s13360-025-06337-6","DOIUrl":"10.1140/epjp/s13360-025-06337-6","url":null,"abstract":"<div><p>Bacterial diseases significantly impact human health and the economy, posing serious challenges to societal well-being. Psychological fear of infection motivates behavioral changes to reduce contacts with infected individuals. Awareness campaigns play a crucial role in educating the public about precautionary measures, thereby reducing the likelihood of bacteria ingestion from contaminated sources. Furthermore, individuals who are informed through such campaigns often implement sanitation practices that help to reduce bacterial density in the environment. This study develops a nonlinear mathematical model to analyze the effects of psychological fear, media-induced awareness, and sanitation practices on bacterial disease dynamics. The model considers infection transmission through direct contacts with infected individuals and indirect exposure to environmental bacteria, assuming bacterial density increases proportional to the infected population. Results show that psychological fear, media-driven awareness, and sanitation play crucial roles in shaping bacterial disease dynamics. A higher growth rate of media advertisements induces limit cycle oscillations in the system via Hopf-bifurcation. However, these oscillations diminish when psychological fear surpasses a threshold. Furthermore, it is found that increasing efficacy of media advertisements in promoting precautionary behaviors and enhancing the depletion rate of bacteria through sanitation efforts by aware individuals can reduce disease prevalence. However, these measures may also induce periodic oscillations by lowering the Hopf-bifurcation threshold for media advertisements growth. An increase in the depletion rate of bacteria due to sanitation efforts can also lead to stability switch via double Hopf-bifurcation, underscoring the need for balanced sanitation strategies to prevent oscillations while ensuring effective disease control.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073699","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":"Hydrothermal growth of reduced graphene oxide doped with nitrogen and sulfur for photodiode applications","authors":"Alaa T. Ahmed,&nbsp;E. M. El-Menyawy,&nbsp;T. Abdallah,&nbsp;G. M. Youssef","doi":"10.1007/s00339-025-08581-0","DOIUrl":"10.1007/s00339-025-08581-0","url":null,"abstract":"<div><p>In this study, reduced graphene oxide (rGO) is synthesized using various reducing agents through a hydrothermal method and subsequently employed in fabricating photodiodes. Initially, graphene oxide (GO) is synthesized, and its molecular structure, crystalline nature, and morphology are examined using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Hydrazine hydrate, thiourea, and their mixture are used as reducing agents to produce rGO. The results showed that rGO synthesized using hydrazine hydrate and the mixture of hydrazine hydrate and thiourea exhibited a crystalline structure, whereas rGO synthesized using thiourea alone had an amorphous structure. The optical properties, including the absorption and photoluminescence spectra of the prepared rGO, are investigated. X-ray photoelectron spectroscopy (XPS) is used to analyze the reduction of GO and the doping of nitrogen (N) and sulfur (S) atoms. The three types of rGO are dispersed in chlorobenzene, and the solutions are sonicated to ensure homogeneity. These solutions are then deposited onto n-Si substrates to fabricate photodiodes. The current–voltage (I-V) characteristics of the diodes are measured under dark and illuminated conditions. Key diode parameters, including the ideality factor, potential barrier height, and series resistance, are calculated for all three devices. The photoconduction behavior of the diodes is also analyzed, and their photosensitivity and photoresponsivity are estimated and compared to evaluate the performance of the heterojunction diodes.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00339-025-08581-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073617","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":"Neutrino mass and mixing from a novel scenario with (A_4) symmetry","authors":"V. V. Vien","doi":"10.1140/epjp/s13360-025-06346-5","DOIUrl":"10.1140/epjp/s13360-025-06346-5","url":null,"abstract":"<div><p>We propose a standard model (SM) extension with <span>(A_4)</span> symmetry giving rise to the desired neutrino mass matrix structure with the suitable correlation <span>((M_nu )_{22}= -2 (M_nu )_{13})</span> by the contributions of the Weinberg-type operators and the type-I seesaw mechanism. We find the parameters of the model that can predict the sum of neutrino masses, the effective neutrino mass, the Dirac and Majorana CP phases for both the normal ordering (NO) and the inverted ordering (IO). Our analysis reveals a narrow range for the sum of neutrino masses, approximately 131 meV for NO and 157 for IO, two mass squared differences <span>(Delta m_{21}^2in (52.390, 99.390), mathrm{meV}^2)</span> and <span>(Delta m_{31}^2in (2.528, 2.570)10^3,mathrm{meV}^2)</span> for NO, while <span>(Delta m_{21}^2in (52.500, 99.350), mathrm{meV}^2)</span> and <span>(Delta m_{31}^2in (-2.475, -2.426)10^3,mathrm{meV}^2)</span> for IO, and the Dirac phase <span>(s_delta in (-0.289, -0.146))</span> for IO and <span>(s_delta in (-0.970, -0.968))</span> for IO. Utilizing these constraints, we determine the effective Majorana mass, two Majorana phases and the lightest neutrino mass for both NO and IO. Finally, we estimate the magnitude of the Yukawa-like couplings which can naturally account for the charged-lepton and neutrino mass hierarchies.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073657","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":"Ultra-high-energy event KM3-230213A constraints on Lorentz Invariance Violation in neutrino sector","authors":"Petr Satunin","doi":"10.1140/epjc/s10052-025-14240-8","DOIUrl":"10.1140/epjc/s10052-025-14240-8","url":null,"abstract":"<div><p>We discuss the constraints on superluminal neutrino Lorentz Invariance Violation (LIV) parameters from the observation of the ultra-high-energy event KM3-230213A by the KM3NeT collaboration in cases of linear <span>(n=1)</span> and quadratic <span>(n=2)</span> LIV scenarios. Assuming extragalactic origin of the event, we obtain the constraints on LIV mass scale <span>(Lambda _{n=1} = 1.1 times 10^{30}, text{ GeV })</span> and <span>(Lambda _{n=2} = 1.1 times 10^{19}, text{ GeV })</span> from the absence of neutrino splitting.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14240-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073701","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":"Room temperature ammonia gas sensor based on Ti-doped CeO2 thin films prepared by nebulizer spray pyrolysis method","authors":"Sivaramakrishnan Subramanian,&nbsp;Karupputhevar Neyvasagam,&nbsp;S. Valanarasu,&nbsp;V. Ganesh,&nbsp;I. S. Yahia,&nbsp;Ramesh Ade","doi":"10.1007/s00339-025-08569-w","DOIUrl":"10.1007/s00339-025-08569-w","url":null,"abstract":"<div><p>In the present study, nebulizer spray pyrolysis was used as the technique to synthesize thin films of CeO₂: Ti (0, 1, 2, 3, 4 and 5 wt%). The analysis of the synthesized thin films was carried out using XRD analysis, FESEM analysis, EDX analysis, UV–Vis spectroscopy, PL spectrometry and gas sensing studies. The XRD studies confirmed that the prepared CeO₂: Ti thin films exhibit fcc fluorite structure. No additional phases were observed, indicating that the Ti dopant atoms occupied substitutional positions in the lattice. Each increment to dopant concentration was found to enhance the grain size while substitution by dopant of smaller radii contributed to a decrease in lattice parameter with increasing dopant concentration. EDX results confirmed the addition of dopants to the host lattice in stoichiometry. The band gap, determined from Tauc plot using transmittance data, decreases with increasing dopant concentration. The lowest band gap of 3.03 eV was observed for CeO₂: Ti (4%) thin film, compared to 3.34 eV for the pristine CeO₂ thin film. The prominent visible lines of the photoluminescence spectra could be attributed to oxygen vacancies created due to the spillover effect of doping with Ti. CeO₂: Ti (4%) sample showed a gas response of 5910 to 250 ppm ammonia gas concentration. The sensor also showed response and recovery time of 14.9 s and 11.2 s respectively. The sensor exhibited significant gas response to ammonia in a near-linear gas response characteristic with quick temporal response, high selectivity towards ammonia over VOCs against which it was tested, and a calibratable linear response to relative humidity. The sensor also showed good repeatability and aging characteristics with a detection limit of 26 ppb making CeO₂:Ti (4%) a good material for ammonia gas sensing applications.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073802","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":"Wave modes and gravitational instability in degenerate quantum plasmas including radiation pressure and viscoelastic effects","authors":"Ravinder Bhambhu,&nbsp;Jyoti Turi,&nbsp;Ram Prasad Prajapati","doi":"10.1140/epjp/s13360-025-06344-7","DOIUrl":"10.1140/epjp/s13360-025-06344-7","url":null,"abstract":"<div><p>The wave modes and linear Jeans instability in the ultra-relativistic degenerate strongly coupled quantum plasma have been studied using the quantum hydrodynamic fluid description considering the influence of radiation pressure, Ohmic diffusivity and uniform rotation. The modified equation of state is considered in the fluid model, which includes the effects of radiation pressure of weakly coupled, degenerate, and ultra-relativistic electrons and non-degenerate strongly coupled ions. The general dispersion relation is analytically derived using the normal mode analysis and examined in the transverse and longitudinal modes of propagation in hydrodynamic and kinetic limits. The Jeans instability criterion depends upon the characteristic wave speed of the system modified due to radiation pressure, electron degeneracy pressure, and ion gas pressure. For an infinitely conducting fluid, the Alfvén speed is observed to intervene in the instability condition and modify the critical Jeans wavenumber in transverse propagation. The graphical illustrations show that the growth rate of Jeans instability in the kinetic limit is significantly reduced due to the prominent role of radiation pressure, compressional viscoelastic effects, electron degeneracy pressure, fluid rotation, and quantum corrections. The dispersion properties of wave modes and linear instabilities are analyzed in various limiting cases of interest. The present theoretical results have been applied to understand the gravitational collapse of white dwarfs, and it is observed that perturbations of wavelength larger than the Jeans length <span>({lambda _{text{J}}} simeq 1.7 times {10^5};{text{km}})</span> make white dwarfs gravitationally unstable.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073698","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":"Polarized image of an equatorial emitting ring around a rotating braneworld black hole","authors":"Xin Qin,&nbsp;Songbai Chen,&nbsp;Xiangyun Fu,&nbsp;Yang Huang,&nbsp;Jiliang Jing","doi":"10.1140/epjc/s10052-025-14285-9","DOIUrl":"10.1140/epjc/s10052-025-14285-9","url":null,"abstract":"<div><p>We have studied the polarized image of an equatorial emitting ring around a rotating braneworld black hole. This black hole possesses a tidal charge parameter <i>b</i>, which describes the effects of the free gravitational field in the bulk on the brane. Results show that the effects of the tidal charge parameter on the polarized image depend on the magnetic field structure, the observer inclination, the velocity of the fluid and the radii of the emitting ring. For a given value of the rotation parameter, the observed polarization intensity increases monotonously with <i>b</i> when the magnetic field lies in the equatorial plane, while it no longer changes monotonically with <i>b</i> when the magnetic field is perpendicular to the equatorial plane. The effect of parameter <i>b</i> on polarized images is similar in both stronger and weaker gravitational fields when the magnetic field is within the equatorial plane, and the differences in polarization vectors for different <i>b</i> become noticeable in stronger gravitational fields. We also probe the effects of <i>b</i> on the Stokes Q-U loops.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14285-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074007","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":"On time slices, time complexity, and energy increase in implementing quantum adiabatic evolution by circuit model","authors":"Jie Sun,&nbsp;Ling Qian,&nbsp;Dunbo Cai,&nbsp;Zhiguo Huang,&nbsp;Songfeng Lu","doi":"10.1140/epjd/s10053-025-01003-z","DOIUrl":"10.1140/epjd/s10053-025-01003-z","url":null,"abstract":"<p>In this paper, motivated by previous related works on a kind of quantum local adiabatic evolution, we mainly study the circuit model of its corresponding quantum global adiabatic search algorithm, in which the evolving paths functions in the system Hamiltonian have a general form instead of the usual linear interpolating ones which are widely investigated in the literature. The main conclusion found here can be summarized as follows. Though this quantum adiabatic computation can demonstrate various algorithmic performances, when considering implementing it by a quantum circuit, the time slices thus produced always keep as an invariant which is proportional to inverse square of the overlap between the initial and final states in the problem of interest and also equal to that of multiplying the time complexity and the energy together, by noting that compared with the usual adiabatic evolutions, there is being a great increase of energy of the system. As far as we know, the result exposed here is new and is hoped to be useful for further understanding the kind of quantum adiabatic evolution itself and its connection with the quantum circuit model. Also, we hope the main conclusion here will be ubiquitous when considering applying this kind of quantum adiabatic evolution to solve the problems beyond quantum search.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 5","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073924","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}