The European Physical Journal Plus最新文献

{"title":"Cross-section measurements of ((alpha), (gamma)) reactions on zinc isotopes using the 4(pi) (gamma)-summing method for astrophysics applications","authors":"S. Harissopulos,&nbsp;G. Provatas,&nbsp;V. Foteinou,&nbsp;M. Axiotis,&nbsp;H.-W. Becker,&nbsp;A. Lagoyannis,&nbsp;E. Vagena,&nbsp;P. Dimitriou","doi":"10.1140/epjp/s13360-025-06303-2","DOIUrl":"10.1140/epjp/s13360-025-06303-2","url":null,"abstract":"<div><p>The cross sections of the (<span>(alpha)</span>, <span>(gamma)</span>) reactions on ⁶⁴Zn, ⁶⁶Zn, and ⁶⁸Zn were measured using the 4<span>(pi)</span> <span>(gamma)</span>-summing method at center-of-mass energies relevant to the <span>({ p})</span>-process nucleosynthesis, ranging from 4.756 to 9.352 MeV, with isotopically enriched targets. The paper also reports the analysis procedure for the current and previous measurements, through which the uncertainty of the absolute efficiency of the employed 4<span>(pi)</span> <span>(gamma)</span>-summing NaI(Tl) detector was significantly reduced to <span>(approx)</span>4%. This allowed for testing existing global models of the <span>(alpha)</span>-particle-nucleus optical model potential with increased sensitivity. The experimental cross-section data and resulting astrophysical S factors were compared with corresponding statistical model calculations performed using version 2.0 of the nuclear reaction code TALYS. The conclusions drawn from this comparison are presented and discussed. Additionally, the reaction rates of the three reactions investigated were calculated and compared with well-established and widely used reaction-rate databases.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06303-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143938292","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":"Construction of a quantum Carnot refrigerator for general working substances","authors":"Ferdi Altintas","doi":"10.1140/epjp/s13360-025-06211-5","DOIUrl":"10.1140/epjp/s13360-025-06211-5","url":null,"abstract":"<div><p>A general framework is proposed for constructing a six-stroke irreversible Carnot refrigerator with a working medium characterized by discrete, non-scalable energy levels. A working substance-dependent correction to the coefficient of performance (COP) is expressed in terms of a positive lag term, establishing the ideal Carnot COP as the upper bound for general working media. Three distinct design scenarios for the Carnot refrigerator cycle are presented. Two dipole-coupled spins in a tunable field are employed as the working substance. A comparison of work input, cooling heat, and COP is conducted for the coupled working medium under three design scenarios. The study highlights qualitative differences between the approaches, particularly in the coupled spin case, providing valuable insights into the performance and limitations of refrigeration cycles under varying operational constraints.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06211-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143938291","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":"Role of de Rham–Gabadadze–Tolley like massive gravity on stellar structure fluids","authors":"Allah Ditta,&nbsp;Piyali Bhar,&nbsp;Fakhranda Afandi,&nbsp;Muhammad Aslam,&nbsp;M. Y. Malik,&nbsp;G. Mustafa","doi":"10.1140/epjp/s13360-025-06202-6","DOIUrl":"10.1140/epjp/s13360-025-06202-6","url":null,"abstract":"<div><p>The main goal of this work is to investigate the dynamic properties of a spherically symmetric anisotropic compact star model. This study is carried out within the context of Tolman-Kuchowiz spacetime with substantial de Rham-Gabadadze-Tolley like massive gravity. We used the observed mass and radius estimates for the compact star model <span>(PSR ;J0437-4715)</span> to evaluate the behavior of the anisotropic fluid and the stability of the compact star. The fundamental results are graphically analyzed and the other findings are comprehensively tabulated. We also discuss the mass-to-radius relationship graphically for compact star candidates <span>( Cen;X-3,;LMC;X-4; &amp; ;SMC;X-1)</span>. Through our analysis, we found that our stellar models are stable and well-behaved.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930049","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":"Deterministic and stochastic dynamics of seed dispersal mutualism: a study on density-dependent mechanism","authors":"Tao Feng,&nbsp;Jiayin Zhang,&nbsp;Chenbo Liu","doi":"10.1140/epjp/s13360-025-06325-w","DOIUrl":"10.1140/epjp/s13360-025-06325-w","url":null,"abstract":"<div><p>Seed dispersal mutualism, where animals disperse seeds and plants provide nutritional rewards, is critical to maintaining biodiversity and ecosystem stability. This study develops a stochastic model to investigate how animals enhance plant survival by reducing seed density dependence, extending previous deterministic frameworks. Deterministic analysis identifies conditions for species survival, extinction, and coexistence, revealing that reduced density dependence stabilizes animal-only equilibria but is less effective in promoting coexistence compared to mechanisms that enhance seed germination. Stochastic analysis shows that moderate environmental noise significantly improves species persistence at low densities by rapidly driving the system toward coexistence, whereas intense environmental fluctuations accelerate extinction. Specifically, the model predicts extinction with probability one once noise surpasses a critical threshold. These findings highlight the dual effects of stochasticity on ecological stability and provide analytical methods broadly applicable to interdisciplinary research in physics, mathematical biology, and environmental sciences.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932282","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":"Entanglement Islands from Hilbert space reduction","authors":"Debarshi Basu,&nbsp;Qiang Wen,&nbsp;Shangjie Zhou","doi":"10.1140/epjp/s13360-025-06320-1","DOIUrl":"10.1140/epjp/s13360-025-06320-1","url":null,"abstract":"<div><p>In this paper, we propose a mechanism to generate entanglement islands in quantum systems from a purely quantum information perspective. More explicitly we show that, if we impose certain constraints on a quantum system by projecting out certain states in the Hilbert space, it is possible that for all the states remaining in the reduced Hilbert space, there exist subsets <span>(I_a)</span> whose states are encoded in the states of another subset <span>(mathcal {R}_a)</span>. Then, the subsets <span>({I_a})</span> are just the entanglement islands of the corresponding subsets <span>({mathcal {R}_a})</span>. We call such a system <i>self-encoded</i> and find that the entanglement entropy in such systems should be calculated by a new <i>island formula</i>. We give a comparison between our new island formula and <i>island formula</i> in gravitational theories. Inspired by our mechanism, we propose a simulation of the AdS/BCFT correspondence and the island phases in this context via a holographic <span>(hbox {CFT}_2)</span> with a special Weyl transformation.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925579","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":"Beam energy dependence of transverse momentum distribution and elliptic flow in Au–Au collisions using HYDJET++ model","authors":"Satya Ranjan Nayak,&nbsp;Saraswati Pandey,&nbsp;B. K. Singh","doi":"10.1140/epjp/s13360-025-06298-w","DOIUrl":"10.1140/epjp/s13360-025-06298-w","url":null,"abstract":"<div><p>In this work, we present the particle ratios, transverse momentum spectra, and elliptic flow (<span>(v_2)</span>) of <span>(pi ^pm ,k^pm ,)</span> <i>p</i>, and <span>(bar{p})</span> in Au–Au collisions at <span>(sqrt{s_{NN}}=)</span> 62.4, 39.0, 27.0, 19.6 and 11.5 GeV using HYDJET++ model. The particle ratios match the experimental data that validates the Cleymans-Reidlich parameterization of freeze-out parameters at lower beam energies under the HYDJET++ framework. The lower collision energies produce a system of high baryon chemical potential (<span>(mu _B)</span>) and have a lower inelastic cross section. The interplay between these effects affects the overall shape of the <span>(p_T)</span> spectra. The HYDJET++ model calculations for <span>(p_T)</span> spectra agree well with the available experimental data. The invariant yield ratio of central and peripheral collisions is independent of beam energy. The elliptic flow is calculated based on the scaling between initial and final azimuthal spatial anisotropy (<i>k</i>). This interpretation of <span>(v_2)</span> successfully describes the experimental data for all the collision energies studied in this work. The positive correlation of <i>k</i> with beam energy leads to a small <span>(v_2)</span> at lower collision energies. The hadrons containing strange quarks tend to have smaller values of <i>k</i> than the non-strange hadrons.\u0000</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925577","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":"Genuine multipartite entanglement measure based on (alpha )-concurrence","authors":"Ke-Ke Wang,&nbsp;Zhi-Wei Wei,&nbsp;Shao-Ming Fei","doi":"10.1140/epjp/s13360-025-06324-x","DOIUrl":"10.1140/epjp/s13360-025-06324-x","url":null,"abstract":"<div><p>Quantifying genuine entanglement is a crucial task in quantum information theory. Based on the geometric mean of bipartite <span>(alpha )</span>-concurrences among all bipartitions, we present a class of well-defined genuine multipartite entanglement (GME) measures G<span>(alpha )</span>C with one parameter <span>(alpha )</span> for arbitrary multipartite states. We show that the G<span>(alpha )</span>C is of continuity for any multipartite pure states. By utilizing the related symmetry, analytical results of G<span>(alpha )</span>C are derived for any <i>n</i>-qubit GHZ states and W states, which show that the GHZ states are more genuinely entangled than the W states. With explicit examples, we demonstrate that the G<span>(alpha )</span>C can distinguish different GME states that other GME measures fail to. These results justify the potential applications of G<span>(alpha )</span>C in characterizing genuine multipartite entanglements.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925578","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":"Comparative analysis of charged particle distributions and model predictions for underlying events with track-based selection in 13 TeV pp collisions","authors":"H. I. Alrebdi,&nbsp;M. Ajaz,&nbsp;M. Waqas,&nbsp;M. A. Ahmad,&nbsp;Maryam Waqar,&nbsp;A. M. Quraishi,&nbsp;J. H. Baker,&nbsp;S. Jagnandan,&nbsp;A. Jagnandan","doi":"10.1140/epjp/s13360-025-06319-8","DOIUrl":"10.1140/epjp/s13360-025-06319-8","url":null,"abstract":"<div><p>In this study, we conduct a comprehensive analysis of charged particle distributions that are particularly sensitive to underlying events. We employ simulations from three distinct models: EPOS4, Pythia8.3, and QGSJETII. These simulations are subsequently compared to experimental measurements obtained by the ATLAS experiment in proton–proton collisions at a center-of-mass energy of <span>(sqrt{s} = 13)</span> TeV. The analysis is conducted under specific kinematic conditions, with a focus on physical observables within the region defined by <span>(|eta | &lt; 2.5)</span> and <span>(p_{T} &gt; 0.5)</span> GeV. A comparison of model predictions with data reveals that EPOS4 and Pythia8.3 consistently provide favorable results for various distributions, including mean charged particle densities, mean multiplicities, and average transverse momentum. The QGSJETII-04 model performs well at low <span>(p^{lead}_{perp })</span> and low <span>(N_{ch})</span>, but under-predicts data in some distributions. EPOS4 stands out as having more accurate results, attributed to its detailed treatment of parton saturation and hydrodynamic effects, while Pythia8.3 benefits from parameters such as color reconnection and multi-parton interaction. The QGSJET focuses on cosmic-ray air showers and less on collective effects, highlighting the need for careful model selection to accurately represent particle collision physics. Furthermore, we employ a thermodynamically consistent Tsallis distribution function to extract parameter values for comparison purposes. Our findings reveal that the parameter values extracted from the fit function align more closely with the data for the EPOS4 and Pythia8.3 models, indicating that these two models provide a better representation of the experimental observations as compared to QGSJETII-04.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919042","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":"Impact of hospital bed availability on infectious disease management: a stochastic and optimal control approach","authors":"Nawaj Sarif,&nbsp;Arjun Kumar,&nbsp;Uma S. Dubey,&nbsp;Balram Dubey,&nbsp;Sahabuddin Sarwardi","doi":"10.1140/epjp/s13360-025-06294-0","DOIUrl":"10.1140/epjp/s13360-025-06294-0","url":null,"abstract":"<div><p>This study examines a susceptible-infected-temporary-permanent-recovered (SITHR) epidemic model incorporating the Holling type II incidence rate to prevent and control the disease with optimal use of hospital beds. Initially, the well-posedness and feasibility of the model are analyzed, and then valid biological equilibrium points are calculated. Subsequently, the stability of these equilibrium points is assessed and the basic reproduction number <span>((R_0))</span> is calculated as a threshold value that controls the dynamics of the disease. The proposed model undergoes several bifurcations, including transcritical (backward and forward), saddle-node, Hopf, and Bogdanov–Takens bifurcations. The normal form is derived to demonstrate the presence of a Bogdanov–Takens bifurcation. Furthermore, parameter estimation is conducted using COVID-19 data from Italy to refine the model’s accuracy and boost the reliability of the study’s predictions. Using the normalized forward sensitivity index (NFSI), a sensitivity analysis of parameters associated with the basic reproduction number is performed, and the partial rank correlation coefficient (PRCC) is calculated to locate the key parameters affecting disease transmission dynamics. Moreover, the system is expanded to incorporate time-dependent control variables to reduce the infected population and the cost associated with implementing these controls. The developed optimal control system is employed to build the Hamiltonian function, which is solved using Pontryagin’s maximum principle. Also, a cost-effectiveness analysis is performed to evaluate the economic efficiency of various intervention strategies. Beyond the deterministic framework, the study includes formulations for continuous-time Markov chains and stochastic differential equations to assess the impact of environmental noise on the system. Moreover, the Galton–Watson branching process determines the extinction threshold for the stochastic model and sets the parameters that govern disease extinction or persistence. Finally, numerical simulations are demonstrated to illustrate the impact of changes in system parameters on the dynamic behavior of the model. These findings will enhance preparedness and enable more efficient responses to health emergencies, leading to better patient care and less pressure on healthcare systems.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143925621","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":"Modular apparatus for nuclear reactions spectroscopy (MARS): characterization and first application to determine (^{12})C((^6)Li,(^4)He)(^{14}hbox {N}^{g.s}) nuclear reaction cross sections","authors":"L. Garrido-Gómez,&nbsp;A. Vegas-Díaz,&nbsp;M. A. G. Alvarez,&nbsp;J. P. Fernández-García,&nbsp;B. Fernández,&nbsp;F. J. Ferrer,&nbsp;D. Lopez-Aires","doi":"10.1140/epjp/s13360-025-06305-0","DOIUrl":"10.1140/epjp/s13360-025-06305-0","url":null,"abstract":"<div><p>This work presents MARS (Modular apparatus for nuclear reactions spectroscopy) and its characterization prior to its first application to measure <span>(^6)</span>Li+<span>(^{12})</span>C nuclear reactions. Measurements were performed at the 3 MV tandem accelerator of the CNA (National Accelerator Center), in Seville, Spain. The <span>(^{6})</span>Li projectiles were accelerated at energies around the <span>(^6)</span>Li+<span>(^{12})</span>C Coulomb barrier (<span>(V^{text {cm}}_{B}sim 3.0)</span> MeV - center of mass and <span>(V^{text {lab}}_{B}sim 4.5)</span> MeV - laboratory frame). Using a <span>(^{6}hbox {Li}^{2+})</span> beam, we measured at 13 laboratory energies from 4.00 to 7.75 MeV. Thus, we present the excitation function of <span>(^{12})</span>C(<span>(^6)</span>Li,<span>(^4)</span>He)<span>(^{14}hbox {N}^{g.s.})</span> reaction, at 2 backward angles (<span>(110.0^circ )</span> and <span>(140.0^circ )</span>). The projectile dissociation, leading to this reaction, increases with the bombarding energies around the Coulomb barrier. This dissociation is favored at an optimum energy <span>(E_{b}^{text {op}})</span> <span>(ge )</span> <span>(V_{B})</span> + <span>(|Q_{bu}|)</span>, where <span>(V_{B})</span> is the Coulomb barrier of the system, and <span>(|Q_{bu}|)</span> is the module of <i>Q</i>-value for the <span>(^6)</span>Li dissociation into <span>(^4)</span>He+<span>(^2)</span>H. This result corroborates a systematic analysis of weakly bound projectiles reacting on several targets [1].</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06305-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143913798","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}