物理最新文献

{"title":"Optimization of inverse one-qubit refrigerators","authors":"J. J. Fernández","doi":"10.1140/epjp/s13360-025-06313-0","DOIUrl":"10.1140/epjp/s13360-025-06313-0","url":null,"abstract":"<div><p>We study several optimal working regimes of one-qubit quantum refrigerators having one qubit at their cold side. We demonstrate that they can be optimized using the techniques of finite-time thermodynamics on the solutions of the Lindblad equation. Our results show that differently to what happens in classic refrigerators, in our quantum ones the optimization of the cooling power does not lead to an optimal working regime but that using the <span>(Omega)</span> function we can find it. Then, we generalize the study using a family of target functions defined by powers of the coefficient of performance times the cooling power to carry out a more general optimization. These last optimizations reveal the importance that every parameter defining the refrigerator has on the performance of the refrigerators when they work optimally.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-025-06313-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140135","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":"Insights into the Vakhnenko–Parkes equation: solitary waves under the influence of power-law nonlinearity","authors":"Turgut Ak,&nbsp;Sharanjeet Dhawan,&nbsp;Mostafa M A Khater,&nbsp;Abdul Hamid Kara","doi":"10.1007/s12043-025-02929-0","DOIUrl":"10.1007/s12043-025-02929-0","url":null,"abstract":"<div><p>In this study, we identify two distinct families of solutions for the Vakhnenko–Parkes (VP) equation using a hybrid computational scheme. This methodology, referred to as the hybrid scheme, integrates B-spline functions with a finite-element approach. The notable advantage of this scheme is its unconditional stability, which enables the successful development of both topological and non-topological solutions. To demonstrate its efficacy, several test cases are examined. We visualise the dynamics of topological and non-topological solitary wave profiles by presenting results through figures and calculating the associated errors. Furthermore, we derive an analytical solution using the Khater II technique and compute conservation laws. In summary, our findings suggest that the presented scheme is highly effective and adaptable to various other nonlinear models.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135275","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":"Circular motion, QPOs testing, emission energy and thermal fluctuations around a non-singular hairy Bardeen black hole","authors":"G. Mustafa,&nbsp;Allah Ditta,&nbsp;Tayyab Naseer,&nbsp;S. K. Maurya,&nbsp;Phongpichit Channuie,&nbsp;Awad A. Ibraheem,&nbsp;Farruh Atamurotov","doi":"10.1140/epjc/s10052-025-14235-5","DOIUrl":"10.1140/epjc/s10052-025-14235-5","url":null,"abstract":"<div><p>We investigate the dynamics of test particles around a spherically symmetric, non-rotating hairy-Bardeen black hole, and then study the influence of the model’s parameters on the particle motion. The black hole is fully characterized by five parameters, the mass <i>M</i> of the black hole, the charge <i>Q</i> of the black hole, coupling constant <span>(beta )</span>, the parameter <span>(gamma )</span> describing the hair of the black hole, and a BH parameter <span>(eta )</span>. Using the effective potential technique, we study the stability and instability of circular equatorial orbits. We calculate the analytical expressions for the energy and angular momentum of test particles as functions of black hole parameters. The effective forces acting on particles as well as the innermost stable circular orbits have also been studied. Epicyclic oscillations of test particles close to the equatorial plane are explored, and analytical expressions for radial, vertical, and orbital frequencies have been derived. We also investigated the frequency of periastron precession of the particles. We also study the thermal properties showing the emission rate of energy and thermal fluctuation by calculating the Hawking temperature. Our findings reveal that the black hole model’s parameters significantly impact particle motion.\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 5","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14235-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135506","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":"Controlling vortex matter via a superconducting nano-bridge sample","authors":"C. A. Aguirre,&nbsp;J. Faúndez,&nbsp;P. Díaz,&nbsp;D. Laroze,&nbsp;A. S. Mosquera,&nbsp;N. C. Costa,&nbsp;J. Barba-Ortega","doi":"10.1007/s00339-025-08644-2","DOIUrl":"10.1007/s00339-025-08644-2","url":null,"abstract":"<div><p>A fundamental understanding of superconducting nanodevices is required to develop emerging quantum technologies. We use time-dependent Ginzburg-Landau theory to investigate the magnetic response of a three-dimensional monolithic superconducting nano-bridge in the presence of two external magnetic fields. Our analysis focuses on the behavior of the Gibbs free energy density, magnetization, superconducting Cooper pair density, current flow as a function of geometry, external magnetic fields, and induced currents. In three distinct cases, we explore the interplay between geometry, induced current, and vortex dynamics. First, we analyze the stability of vortices under variations of the geometry without induced currents. Second, we examine the influence of induced currents (given by a second external magnetic field) on the left single boundary of the superconducting nano-bridge sample while keeping the geometric parameters fixed. Third, we introduce left and right-induced currents at the boundaries and investigate their impact on vortex nucleation. Our results demonstrate that the nano-bridge dimensions play a crucial role in stabilizing and controlling single-vortex states in the nano-bridge sample. We find that induced currents generate vortex motion within the superconducting nano-bridge sample, highlighting the intricate dependence of vortex dynamics on currents under geometrical constraints. Our findings provide valuable insights into controlled vortex manipulation in nano-scale superconductors, with potential applications in superconducting electronics and quantum technologies.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140196","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":"Importance of track density for radiolytic reactions: changes in yields of OH radical molecular probe under protons around the Bragg peak","authors":"Tamon Kusumoto,&nbsp;Yu Okazaki,&nbsp;Taisei Mamiya,&nbsp;Masakazu Oikawa,&nbsp;Teruaki Konishi","doi":"10.1140/epjp/s13360-025-06391-0","DOIUrl":"10.1140/epjp/s13360-025-06391-0","url":null,"abstract":"<div><p>The aim of the present study is to elucidate the mechanisms of sparing effects of tissues observed under ultra-high-dose rate (UHDR: &gt; 40 Gy/s) irradiations. To do so, under Bragg peak energy protons, we evaluate changes in OH radicals, that efficiently react with DNA and proteins, consequently, they govern the indirect action, by varying the spatial distribution of proton tracks, while maintaining absorbed dose rate. By applying beam with 2 μm × 2 μm (“micro” beam), yields of OH radicals decrease by − 38 ± 7%, compared to that with 100 μm × 100 μm (“macro beam). The present results show that radical–radical reactions between neighboring tracks occur by UHDR irradiations even around the Bragg peak energy. Additionally, radical–radical reactions, leading the reduction of yields of OH radicals, are one of the mechanisms of sparing effects seen by UHDR irradiations.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135349","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":"Transmission dynamics of rabies through stochastic analysis with the effect of vaccination in dogs population","authors":"Gul Khan,&nbsp;Rasha Kadri Ibrahim,&nbsp;Abdelaziz Hendy,&nbsp;Sally Mohammed Farghaly Abdelaliem,&nbsp;Ahmed Hendy","doi":"10.1140/epjp/s13360-025-06355-4","DOIUrl":"10.1140/epjp/s13360-025-06355-4","url":null,"abstract":"<div><p>Each year, approximately 55,000 people die from the rabies virus, which is transmitted by dogs. Since deterministic approaches ignore effect randomness, such as different environmental factors that affect the rabies process dynamics. In this study, the stochastic epidemic model with the impact of vaccination for dogs is considered to investigate the transmission dynamics of rabies in the population with white noise effect. Firstly, we demonstrate the existence of a global solution and its positive impact. The basic stochastic reproduction number is then computed as a threshold that determines the persistence or extinction of the disease. If <span>(R_{0}^{s} &lt; 1)</span> then the disease will be extinct from the population. And if <span>(R_{0}^{s}&gt; 1)</span> the disease continues to persist in the population. Finally, we perform the numerical simulation to examine the impact of various parameters on the propagation of disease. The numerical simulation shows that vaccination plays a critical role in the control of the disease. In contrast, the disease spreads when infected dogs met susceptible humans and dogs.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135350","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":"Density functional theory study of phase stability and electronic properties for L12 X3Ru and XRu3 alloys","authors":"B. O. Mnisi,&nbsp;E. M. Benecha,&nbsp;M. M. Tibane","doi":"10.1140/epjb/s10051-025-00956-9","DOIUrl":"10.1140/epjb/s10051-025-00956-9","url":null,"abstract":"<div><p>This study employs first-principles density functional theory (DFT) to investigate the structural, mechanical, electronic, and phonon properties of L1₂-phase X₃Ru and XRu₃ alloys (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn). Our findings indicate that Sc₃Ru, Ti₃Ru, V₃Ru, Mn₃Ru, Zn₃Ru as well as Ru₃Ti, Ru₃V, and Ru₃Mn alloys are thermodynamically stable. All the X₃Ru and XRu₃ alloys exhibit mechanical stability, except for Ti₃Ru and Fe₃Ru. The density of states results reveal metallic behavior across all the X₃Ru and XRu₃ alloys, while charge density plots indicate metallic bonding between X and Ru, consistent with the electronic properties. Phonon dispersion curves confirm the dynamic stability in TiRu₃, VRu₃, CrRu₃, MnRu₃, FeRu₃, CoRu₃, CuRu₃, ZnRu₃ as well as in Cr₃Ru, Cu₃Ru and Co₃Ru alloys. Notably, TiRu₃, VRu₃, MnRu₃ also demonstrate thermodynamic and mechanical stability, along with higher melting temperatures compared to the widely used Ni₃Al alloy. These findings lay a theoretical foundation for further experimental investigations of X₃Ru and XRu₃ alloys, which may be promising candidates for high-temperature structural applications.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 5","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjb/s10051-025-00956-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Luminescent properties of Er3+-Eu3+ co-doped tellurite glass for white light LEDs","authors":"Qun Wang,&nbsp;Ranran Bu,&nbsp;Changyuan Xu,&nbsp;Fengjiao Zhao,&nbsp;Hongming Yin","doi":"10.1007/s00339-025-08629-1","DOIUrl":"10.1007/s00339-025-08629-1","url":null,"abstract":"<div><p>Tellurite glass samples doped with Er³⁺ and Eu³⁺ were synthesized by the high-temperature solid phase method. The XRD diffraction pattern shows the amorphous properties of the prepared samples. The luminescence properties of glass samples were analyzed using the absorption spectrum, excitation spectrum, and emission spectrum. The energy transfer mechanism between Er³⁺ ions and Eu³⁺ ions was studied by changing the concentration of Eu³⁺ ions, and the results were verified by measuring the luminescence decay lifetime. It is worth noting that at 380 nm excitation, Er³⁺ and Eu³⁺ co-doped tellurite glass exhibits remarkable tunable luminescence characteristics: by adjusting the concentration of Eu³⁺ ions, the emission color can be flexibly adjusted from green to orangish-red. In addition, by effectively combining the prepared co-doped glass sample with the 380 nm GaN chip, the cold white light emission with CIE coordinates of (0.324, 0.320) was successfully achieved. According to the variable-temperature spectroscopy, at 210℃, the emission peak intensities of the co-doped Er³⁺/Eu³⁺ tellurite glass at 547 nm and 613 nm are above 70% of the room-temperature luminescence intensity, demonstrating excellent thermal stability.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135450","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":"Tuning the properties of Yb-Doped BiFeO3: insights into structural, electrical, magnetoelectric and photocatalytic behavior","authors":"Asif Nazir Ganie,&nbsp;Iqra Irshad,&nbsp;Mehraj ud Din Rather,&nbsp;Basharat Want","doi":"10.1007/s00339-025-08603-x","DOIUrl":"10.1007/s00339-025-08603-x","url":null,"abstract":"<div><p>The manipulation of electric properties by the magnetic field in magnetoelectric multiferroic materials has fuelled enormous research activity, to realise their potential for magnetoelectric devices. So, this report investigates the influence of ytterbium (Yb³⁺) substitution on the structural, magnetic, and magnetoelectric properties of hydrothermally synthesised bismuth ferrite Bi_1-xYb_xFeO₃ (<i>x</i> = 0.00, 0.20, 0.25, 0.30). Yb³⁺ doping successfully lowers the average grain size, while preserving a distorted rhombohedral structure, within the R3c space group. Notably, Yb-doped bismuth ferrite exhibits enhanced ferromagnetic behaviour, with the Bi_0.7Yb_0.3FeO₃ composition achieving a significant magnetization of 0.337 emu/g. Moreover, the addition of Yb³⁺ causes significant changes in electric polarisation, which significantly impacts the multiferroic properties. A high magnetoelectric coupling coefficient (15.049 mVcm⁻¹Oe⁻¹) for Bi_0.7Yb_0.3FeO₃, highlights its promise for applications in multifunctional devices, where the interplay between magnetic and electric order parameters is critical for advanced technological innovations. The photoluminescence analysis demonstrates a decline in intensity with increasing Yb³⁺ doping, suggesting a lower electron–hole recombination rate. The photocatalytic activity of the synthesized nanoparticles was assessed for methylene blue degradation under visible light exposure, with the 30% doped sample exhibiting the highest efficiency. These results indicate the potential of Yb-doped BiFeO₃ nanoparticles for wastewater treatment applications.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 6","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140195","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":"Constructing degenerate lumped solutions for the (2+1)-dimensional Bogoyavlenskii–Kadomtsev–Petviashvili equation","authors":"Mengru Xu,&nbsp;Biao Li","doi":"10.1140/epjp/s13360-025-06404-y","DOIUrl":"10.1140/epjp/s13360-025-06404-y","url":null,"abstract":"<div><p>By applying Hirota’s bilinear method alongside a novel limiting approach, it is possible to derive degenerate lump solutions that encompass both the anomalous scattering of lumps and the weak interactions among multiple lumps from the <span>(N)</span> soliton solutions of the Bogoyavlenskii–Kadomtsev–Petviashvili equation. Improvements to the traditional limiting methods allow the anomalous scattering of two lumps to be obtained, as well as the asymptotic behavior of the anomalously scattering lumps to be discussed and investigated in detail. In addition, the study derives weak interactions among multiple lumps exhibiting intriguing patterns, such as triangles and quadrilaterals. The dynamic behaviors of these two weak interactions are also analyzed. Furthermore, the interactions between lumps and anomalous scattering lumps are investigated. These unique degenerate lump solutions contribute to a deeper understanding of the characteristics of lumps.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 5","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135351","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}