物理最新文献

{"title":"Dromion solutions of nonlinear BKK equations using the improved F-expansion method","authors":"S-F Wang","doi":"10.1007/s12043-025-02915-6","DOIUrl":"10.1007/s12043-025-02915-6","url":null,"abstract":"<div><p>This article investigates a (2 + 1)-dimensional nonlinear Broer–Kaup–Kupershmidt (BKK) equation and proposes an improved F-expansion method for obtaining analytical soliton solutions. We introduce the F-expansion technique, which involves a Riccati equation and hyperbolic functions. Using this approach, various solutions are obtained and some structures are constructed and classified into three categories: dromion solutions, local excitations and self-similar fractal structures. These solutions contribute to understanding the (2 + 1)-dimensional BKK and give vital insights into wave distributions. To obtain the dynamics of the solutions, some results are discussed and some local excitations and self-similar fractal structures (FSs) are presented. For the trial functions are emerged into the dromion solutions, the fractal structures which are self-similar are observed. The physical insight and the dynamics of the dromion solutions describing the wave propagation transmission in optical physics are discussed for different selections of rational polynomial trial functions in the solutions. The significance of this work lies in the successful application of the proposed method to achieve soliton solutions of (2 + 1)-dimensional BKK. Through symbolic calculation, the analytic soliton solutions are extracted, which is beyond the efforts of the previous literature. This method provides a new perspective for studying the BKK equation and its solutions. The results obtained enhance our understanding of the BKK behaviour and pave the way for the next work in this area.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852508","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":"Constraining the metric-affine bumblebee gravity parameter using black hole shadows and quasiperiodic oscillations of galactic microquasars","authors":"Sohan Kumar Jha,&nbsp;Anisur Rahaman","doi":"10.1140/epjc/s10052-025-14110-3","DOIUrl":"10.1140/epjc/s10052-025-14110-3","url":null,"abstract":"<div><p>We examine a static spherically symmetric black hole metric that originates from the vacuum solution of the traceless metric-affine bumblebee model in which spontaneous Lorentz symmetry-breaking occurs when the bumblebee fields acquire a non-vanishing vacuum expectation value. A free Lorentz-violating parameter enters into the basic formulation of the metric-affine bumblebee model. In this study, we use observations from the Event Horizon Telescope (EHT) collaboration on <span>(M87^*)</span> and <span>(SgrA^*)</span> to analyse the shadow of the black hole and an attempt has been made to constrain that free Lorentz-violating parameter. We also investigate particle motion over time-like geodesics and compute the corresponding epicyclic frequencies. We further constrain the Lorentz-violating parameter by using the reported high-frequency quasi-periodic oscillations (QPOs) of microquasars, offering new insights into its possible impact on astrophysical phenomena.\u0000\u0000</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"85 4","pages":""},"PeriodicalIF":4.2,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-025-14110-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852611","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":"A lead-free flexible piezoelectric nanocomposite nanogenerator, utilizing a hybrid approach based on high-performance synthesized NBT-BCZT nanopowders","authors":"S. Gouthamsri,&nbsp;B. Srikanth,&nbsp;V. Raju,&nbsp;Saripiralla Basammaa,&nbsp;Thiriveedhi Narendrudu,&nbsp;M. Gnana Kiran,&nbsp;Varakumari Samudrala,&nbsp;V. Rajesh,&nbsp;Ganta Anusha,&nbsp;Kuppam Mohan Babu,&nbsp;Bittu Singh","doi":"10.1007/s00339-025-08503-0","DOIUrl":"10.1007/s00339-025-08503-0","url":null,"abstract":"<div><p>Properties of materials play a critical role in the performance of hybrid piezoelectric nanocomposites (HPCs) for nanogenerators. Traditional methods, such as solid-state route, often result in suboptimal mechanical properties, which limit the capabilities of piezoelectric nanogenerators (PENGs). An HPC-based Polydimethylsiloxane (PDMS) polymer with multi-walled carbon nanotube (MWCNT) fillers and the sol-gel-prepared piezoelectric nanopowder material 0.94NBT-0.06BCZT are presented in this work. The effects of varying filler concentrations on the overall performance of the nanocomposites were thoroughly examined. Both the composite materials and nanoparticles were extensively characterized. Structural analyses and Raman spectroscopy, confirmed the high crystallinity and purity of the 0.94NBT-0.06BCZT powder, as well as the formation of a morphotropic phase boundary (MPB) @ RT. Under harmonic excitations, PENGs of 0.94NBT-0.06BCZT produce an output power of 2.41 µW and an open-circuit voltage of 7.2 V for a 280kΩ load resistance. The inclusion of Multi-Walled Carbon Nanotubes (MWCNTs) into Hydroxypropyl Cellulose (HPC) improves the conductivity and promotes self-polarization, thanks to the excellent electrical properties of MWCNTs. These nanostructures, due to their immense surface area and conductive nature, significantly enhance the composite material’s ability to conduct electricity and exhibit self-polarization effects.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 5","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852502","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":"Mismatch synchronization based on 4D memristive chaotic system and its application in image encryption","authors":"Jie Zhang,&nbsp;Jiliang Lv,&nbsp;Nana Cheng,&nbsp;Xiaodong Wei,&nbsp;Liu Yang","doi":"10.1140/epjb/s10051-025-00913-6","DOIUrl":"10.1140/epjb/s10051-025-00913-6","url":null,"abstract":"<div><p>A four-dimensional memristive chaotic system is proposed, and its dynamical characteristics are analyzed through conventional methods. In this system, transient chaos and bursting oscillations of the number of spikes controlled by parameters are also found. This paper also designs physical circuits and digital circuits to confirm the existence of chaotic systems. Additionally, a mismatch synchronization system is introduced, and the synchronization control is achieved using mismatch synchronization principles. Mismatch synchronization is integrated with RNA operation to develop an image encryption algorithm. The analyses show that the image encryption method proposed exhibits better performance.</p><h3>Graphical abstract</h3>\u0000<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 4","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856470","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":"Entangled atoms in a cavity with an electromagnetic field","authors":"Natália M. Alvarenga,&nbsp;Cesar A. Linhares,&nbsp;José André Lourenço,&nbsp;José Roberto P. Mahon,&nbsp;Adolfo P. C. Malbouisson","doi":"10.1140/epjp/s13360-025-06249-5","DOIUrl":"10.1140/epjp/s13360-025-06249-5","url":null,"abstract":"<div><p>We consider a system consisting of two identical particles (‘atoms’), each approximated by a harmonic oscillator, which couples to an electromagnetic field, inside a perfectly reflecting spherical cavity. Differently from the scalar field ohmic case, which is usually considered in similar previous papers, such an electromagnetic environment is instead categorized as a supra-ohmic (or superohmic) one. Through the introduction of center-of-mass and relative-position coordinates and employing the formalism of dressed coordinates and states, we are able to study the time evolution of the entanglement of the atoms. This is done for both large and small cavities, in a nonperturbative fashion. For very large cavities, we find, as expected, an almost exponential decay in time, for both the concurrence and the negativity of the system, while for small ones, these quantities show an irregular oscillation of the entanglement of the atoms, but it does not cease to the exist (there is no sudden death).</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852536","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 processing methods on dispersion, electrical and mechanical properties of MWCNTs/PVC composites","authors":"Yueqing Ren,&nbsp;Xiaojie Sun,&nbsp;Meng Jiang,&nbsp;Bo Feng,&nbsp;Zhihua Han,&nbsp;Yafei Li","doi":"10.1007/s00339-025-08522-x","DOIUrl":"10.1007/s00339-025-08522-x","url":null,"abstract":"<div><p>Multi-walled carbon nanotubes-filled polyvinyl chloride (MWCNTs/PVC) composites are prepared using four processing methods: a conical twin-screw (CTS) extruder, a Haake mixing apparatus, and parallel twin-screw (PTS) extruders with screw length/diameter ratios of 40:1 and 48:1, respectively. The influences of processing methods on filler dispersion, electrical, dynamic, mechanical properties, as well as thermal stability of MWCNTs/PVC composites are investigated. There are many large-sized (hundreds of micrometers) MWCNTs bundles and aggregates in the CTS extruded samples, and the dispersion is the worst. The PTS extruded MWCNTs/PVC composites have relatively better dispersion and the dispersion improves with increase in length/diameter ratio of the screw. The MWCNTs/PVC sample, prepared using the Haake mixer, mixed for 10 min, shows the best dispersion. Improvement of MWCNTs dispersion affects the thermal, electrical and mechanical properties of the composites, leading to increases in surface conductivity, glass transition temperature, flexural modulus, Young’s modulus, and impact strength of the MWCNTs/PVC composites.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 5","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852484","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":"Quark-hadron phase transition through bubble nucleation at finite magnetic field in quark-meson model","authors":"Ume Habiba,&nbsp;Rashid Khan,&nbsp;Spogmay Gul","doi":"10.1140/epjp/s13360-025-06268-2","DOIUrl":"10.1140/epjp/s13360-025-06268-2","url":null,"abstract":"<div><p>We explore the behavior of the first-order transition of quark-hadron matter facilitated through homogeneous bubble nucleation using the quark-meson model at a finite magnetic field (<i>B</i>). With one loop effective potential, we obtain different physical quantities such as surface tension, critical radius of the bubbles, and free energy of the system in thin-wall approximation. The effective potential gets intense with increasing magnetic field, enhancing the symmetry breaking. The surface tension evolution verses temperature (<i>T</i>) and chemical potential (<span>(mu )</span>) for different magnetic fields is analyzed and presented. The evolution of surface tension raises quickly for a finite magnetic field. Similarly, the effect of finite magnetic fields on the critical radius and free energy is presented. We observe, as expected, a divergent behavior of critical radius and free energy as temperature and chemical potential approaches critical values.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852534","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":"Increased thermal stability and dielectric properties of Ba2TiSi2O8-CaTiO3 composites for high frequency applications","authors":"R. F. Abreu,&nbsp;S. O. Saturno,&nbsp;D. da M. Colares,&nbsp;F. A. C. Nobrega,&nbsp;P. M. O. Silva,&nbsp;F. F. do Carmo,&nbsp;J. P. C. do Nascimento,&nbsp;T. O. Abreu,&nbsp;J. C. Sales,&nbsp;M. A. S. da Silva,&nbsp;R. S. da Silva,&nbsp;A. S. B. Sombra","doi":"10.1007/s00339-025-08516-9","DOIUrl":"10.1007/s00339-025-08516-9","url":null,"abstract":"<div><p>This work investigated composites formed from Ba₂TiSi₂O₈ – CaTiO₃ in the microwave region, as well as their dielectric properties, dielectric permittivity (<i>ε’</i>_<i>r</i>), dielectric loss (<i>tan δ</i>), and quality factor (<i>Q x fr</i>). Solid-state synthesis was employed for the preparation of the Ba₂TiSi₂O₈ ceramic matrix and the composites were obtained by mixing the matrix with 1%, 3%, 5% and 9% CaTiO₃ by weight. The structural characterization was performed through X-ray diffraction (XRD), and the phases were confirmed by Rietveld refinement. Scanning electron microscopy (SEM) was performed to analyze the surface morphology of the samples. The temperature coefficient of resonant frequency (<i>τ</i>_<i>f</i>) was obtained to verify the thermal stability of the samples. An analysis of <i>τ</i>_<i>f</i>, obtained through the Silva-Fernandes-Sombra (SFS) method, revealed that the addition of 5% CaTiO₃ provided a significant improvement in the thermal stability of the material (BTS5, <i>τ</i>_<i>f</i> = − 9.57 ppm∙ºC^− 1). It is noteworthy that the value obtained for this parameter is within the range required for applications in electronic devices operating in the microwave region. The Hakki-Coleman method was used to analyze the dielectric properties of the samples in the microwave region, through which it was possible to observe a subtle increase in the dielectric permittivity (11.00 ≤ <i>ε’</i>_<i>r</i> ≤ 16.71) and a decreased level of the dielectric loss (<i>tan δ</i>) of the samples. Finally, the dielectric resonator antenna (DRA) configuration was used to analyze the potential of the samples operating in the HE_11δ mode.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 5","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852504","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":"Excellent red emission via violet-blue excited in aluminate-based phosphors for white LED application","authors":"Huihua Ye,&nbsp;Jinfeng Lin,&nbsp;Xusheng Wang","doi":"10.1007/s00339-025-08510-1","DOIUrl":"10.1007/s00339-025-08510-1","url":null,"abstract":"<div><p>Three types of CaAl₂O₄:Li⁺ phosphors singly doped with Eu³⁺, Sm³⁺, and Ho³⁺ ions were synthesized using high temperature solid-state reaction method, and the effects of rare-earth ions and doping concentration on the crystal structure, thermal stability and luminescence properties were systematically studied. The XRD patterns show that all Ca_{1 − <i>x</i>}Al₂O₄:0.01Li⁺, <i>x</i>Re³⁺ (Re = Eu, Sm, Ho) phosphors are pure monoclinic CaAl₂O₄ phase. And these phosphors can be effectively excited by the characteristic excitation wavelength of the corresponding rare earth ions. Notably, when the doping concentration is less than 15 mol%, the corresponding luminous intensity increases monotonically with the increase of Ho³⁺, while the optimal doping amounts for Eu³⁺ and Sm³⁺ are 9 mol% and 1 mol%, respectively. Additionally, comparative analysis revealed superior energy transfer efficiency from the matrix to the luminescent center in the CaAl₂O₄:0.01Li⁺, Eu³⁺ relative to Sm³⁺ and Ho³⁺ counterparts. More importantly, the Ca_0.91Al₂O₄:0.01Li⁺, 0.09Eu³⁺ phosphors also exhibit excellent thermal and ageing stability. Its luminous intensity exhibited minimal deviation (&lt; 16%) across an extended temperature range (208 ~ 448 K). Furthermore, after 320 h of thermal aging at 100 °C, the sample retained over 98% of its initial fluorescence intensity. This study provides theoretical and experimental basis for the development of CaAl₂O₄-based phosphors for solid-state lighting devices.</p></div>","PeriodicalId":473,"journal":{"name":"Applied Physics A","volume":"131 5","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852505","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":"The mechanism between solar cell efficiency and geometry of truncated quantum dots: implications for practical application","authors":"Naveed Jafar,&nbsp;Rea Bitri,&nbsp;Yixiao Yang,&nbsp;Yueyin Chen,&nbsp;Mojtaba Moghaddasi,&nbsp;Jianliang Jiang","doi":"10.1140/epjp/s13360-025-06244-w","DOIUrl":"10.1140/epjp/s13360-025-06244-w","url":null,"abstract":"<div><p>Quantum dots (QDs) have demonstrated significant potential as key candidates for enhancing the efficiency of intermediate-band solar cells (IBSCs). In this work, we present a theoretical investigation of the impact of truncated conical QD structures on the performance of QD-IBSCs. The Schrödinger equation, solved under the effective mass approximation, provides insight into the electron transition energies between the intermediate and conduction bands and the spatial probability density distribution of carriers within the structure. Our simulation results show strong efficiency dependence on structural parameters, such as QD density, height-to-bottom ratio, and barrier width. Reducing QDs from 20 to 10 results in a 6.54% decrease in electron ground state energy with increasing barrier width and QD height. Further reduction from 10 to 1 QD leads to a minor decrease of 3.75% for barrier width, while an increase in QD height results in a significant reduction of energy up to 11.9%. The power conversion efficiency increases significantly with higher QD densities, reaching 38.9% for 20 QDs compared to 14.7% for a single QD. Similarly, the short-circuit current density varies from 37.7 to 34.4 mA/cm² as the QD height-to-bottom ratio increases. Furthermore, the achieved optimum conversion efficiency is 39.6% for ratio 1. Our findings suggest that optimal performance can be achieved through smaller barrier width, higher QD densities, and larger QD sizes, making truncated conical QDs a promising geometry for next-generation high-efficiency QD-IBSCs.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"140 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852535","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}