The European Physical Journal B最新文献

{"title":"Synthetic data generation with hybrid quantum-classical models for the financial sector","authors":"Otto M. Pires,&nbsp;Mauro Q. Nooblath,&nbsp;Yan Alef C. Silva,&nbsp;Maria Heloísa F. da Silva,&nbsp;Lucas Q. Galvão,&nbsp;Anton S. Albino","doi":"10.1140/epjb/s10051-024-00786-1","DOIUrl":"10.1140/epjb/s10051-024-00786-1","url":null,"abstract":"<p>Data integrity and privacy are critical concerns in the financial sector. Traditional methods of data collection face challenges due to privacy regulations and time-consuming anonymization processes. In collaboration with Banco BV, we trained a hybrid quantum-classical generative adversarial network (HQGAN), where a quantum circuit serves as the generator and a classical neural network acts as the discriminator, to generate synthetic financial data efficiently and securely. We compared our proposed HQGAN model with a fully classical GAN by evaluating loss convergence and the MSE distance between the synthetic and real data. Although initially promising, our evaluation revealed that HQGAN failed to achieve the necessary accuracy to understand the intricate patterns in financial data. This outcome underscores the current limitations of quantum-inspired methods in handling the complexities of financial datasets.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjb/s10051-024-00786-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664429","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":"Labeling small-degree nodes promotes semi-supervised community detection on graph convolutional network","authors":"Yu Zhao,&nbsp;Huiyao Li,&nbsp;Bo Yang","doi":"10.1140/epjb/s10051-024-00817-x","DOIUrl":"10.1140/epjb/s10051-024-00817-x","url":null,"abstract":"<p>Community structure is one of the most important characteristics of network, which can reveal the internal organization structure of nodes. Many algorithms have been proposed to identify community structures in networks. However, the classification accuracy of existing unsupervised community detection algorithms is generally low. Therefore, the semi-supervised community detection algorithm which can greatly improve the classification accuracy by introducing a small number of labeled nodes has attracted much attention. Nevertheless, previous studies were sketchy in terms of label rates and also ignored the variation of classification accuracy under different labeling strategies. In this paper, based on graph convolutional networks, we first study the effect of labeling strategies and label rates on classification accuracy in four real world networks in detail. The research phenomenon is counter-intuitive but surprisingly effective: the classification accuracy of labeling small-degree nodes or random-selection nodes is significantly higher than that of labeling high-degree nodes. The labeling strategies based on acquaintance immune algorithm also prove this result. The interesting question that arises is what topological properties of the network can lead to such results? So we test and verify it in two kinds of synthetic networks. It is found that the phenomenon which labeling small-degree nodes promotes classification accuracy can be observed when the degree distribution of the network follows power-law distribution and the ratio of the external edges of the community to the total edges of nodes in the network is small.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645758","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":"Multistability in a predator–prey model with generalist predator and strong Allee effect in prey","authors":"Subarna Roy,&nbsp;Pankaj Kumar Tiwari","doi":"10.1140/epjb/s10051-024-00814-0","DOIUrl":"10.1140/epjb/s10051-024-00814-0","url":null,"abstract":"<div><p>In this study, we analyze a generalist predator–prey model that includes a strong Allee effect in the prey population. We investigate the positivity and boundedness of solutions, identify ecologically relevant equilibrium points, and determine their stability conditions. Further, we analyze the transcritical, saddle-node, Hopf, Bogdanov-Takens, generalized-Hopf, and cusp bifurcations. Our numerical investigation shows that the model exhibits multiple stable states under similar parametric conditions, driven by bifurcation scenarios linked to the Allee effect. It also underscores the significant role of additional foods for predators in shaping system dynamics, unveiling scenarios ranging from the extinction of predators to their persistence, and the coexistence of both the species. Furthermore, our study delves into the impact of environmental white noise on predator–prey dynamics, introducing stochastic elements. We explore noise-induced transitions between two stable states within the system. Overall, our study highlights the complex dynamics of predator–prey interactions, emphasizing the role of Allee effect and additional food sources.</p></div>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636847","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":"An interdisciplinary research field transformed into an intermedial science exploration programme: how to explore neurotronics research and development in a school student laboratory programme","authors":"Daniel Sacristán,&nbsp;Insa Stamer,&nbsp;Hermann Kohlstedt,&nbsp;Isabella Beyer,&nbsp;Ilka Parchmann","doi":"10.1140/epjb/s10051-024-00807-z","DOIUrl":"10.1140/epjb/s10051-024-00807-z","url":null,"abstract":"<p>This work presents the development and implementation of an interdisciplinary and intermedial science outreach programme designed for school students. The programme integrates biological systems and technological advancements to provide students with hands-on laboratory experiences and immersive media, including virtual reality videos and augmented reality posters. Through a co-creation process involving scientists and educators, the programme aims to enhance students understanding of bio-inspired information pathways and neurogenesis. Preliminary evaluations indicate high engagement and educational value, suggesting that such interdisciplinary approaches can significantly enrich science education.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjb/s10051-024-00807-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636890","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":"Turing patterns in exploited predator–prey systems with habitat loss","authors":"Ramya Seenivasan,&nbsp;Prosenjit Paul","doi":"10.1140/epjb/s10051-024-00815-z","DOIUrl":"10.1140/epjb/s10051-024-00815-z","url":null,"abstract":"<div><p>In this study, we explore the emergence of spatial patterns in a predator–prey model influenced by habitat loss, incorporating the effects of linear diffusion. By examining the stability of the system through the Jacobian matrix, we derive conditions for the occurrence of both Hopf and Turing bifurcations using analytical and numerical approaches. Numerical simulations yield Hopf bifurcation diagrams, revealing the system’s dynamic responses to varying conditions. Our findings contribute to the understanding of how habitat loss and harvesting affect the spatial dynamics in predator–prey systems, which are described by partial differential equations (PDEs) under flux boundary conditions. We also investigate the impact of habitat loss due to harvesting on spatial patterns, identifying formations such as spots and stripes as a result of changes in harvesting efforts. We analytically derive the conditions for Turing instability, which are confirmed through numerical validation.</p></div>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598976","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":"Unveiling the structural, electronic, optical, mechanical, and thermodynamic properties of Mg3ZnO4 in a Caswellsilverite-like structure: a DFT study","authors":"Moufdi Hadjab,&nbsp;Mohamed Issam Ziane,&nbsp;Abderrahim Hadj Larbi,&nbsp;Hamza Bennacer,&nbsp;Mehrdad Faraji,&nbsp;Olga Guskova","doi":"10.1140/epjb/s10051-024-00805-1","DOIUrl":"10.1140/epjb/s10051-024-00805-1","url":null,"abstract":"<div><p>This study investigates the physical properties of the novel mixed metal oxide Mg₃ZnO₄, emphasizing its potential in optoelectronic manufacturing. We provide a comprehensive analysis of its structural, optoelectronic, mechanical, and thermodynamic characteristics, focusing on the ternary compound, which crystallizes in a rocksalt phase similar to the mineral Caswellsilverite. Using advanced density functional theory (DFT) and the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method within the WIEN2k package, we predict the material’s properties in detail. Our structural analysis confirms the stability of Mg₃ZnO₄ in the cubic Pm3̅m space group, revealing key crystallographic parameters. The electronic structure calculations indicate a well-defined energy band gap, confirming its semiconducting nature and suitability for optoelectronic applications. Optical properties, including the dielectric function, absorption, and reflection spectra, demonstrate significant light interaction, highlighting the material’s potential for UV photodetectors and photovoltaic solar cells. The investigation of elastic properties provides critical insights into the mechanical strength and durability of Mg₃ZnO₄, further supporting its viability for demanding applications. Additionally, our thermodynamic analysis reveals the material’s behavior under varying environmental conditions, reinforcing its potential in high-performance optoelectronic devices. These findings establish Mg₃ZnO₄ as a promising candidate for advanced thin-film solar cells and pave the way for future experimental and theoretical studies to explore its unique properties for innovative technological 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":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595560","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":"Dissipative systems have a maximum energy rate density of 105 W/kg","authors":"Martin van Duin","doi":"10.1140/epjb/s10051-024-00785-2","DOIUrl":"10.1140/epjb/s10051-024-00785-2","url":null,"abstract":"<div><p>Mass and energy rate (ER) data have been collected for a wide variety of dissipative systems from the biological, cultural, and cosmological realms. They range from 6 × 10^–25 kg and 3 × 10^–25 W for a synthetic, molecular engine to 1.5 × 10⁵³ kg and 10⁴⁸ W for the observable universe and, thus, span 78 mass and 73 ER orders of magnitude, respectively. The combination of (i) convergence of smaller systems (parts) to a larger system and (ii) scaling of ER as a function of mass with a power law constant β &gt; 0 for groups of systems, explains why the ER and mass data points fall in a diagonal band in the double logarithmic ER <i>vs.</i> mass master plot. There appears to be an ER <i>vs.</i> mass limit, corresponding to an energy rate density (ERD = ER/mass) of around 10⁵ W/kg, separating stable, dissipative systems from unstable, “explosive” systems (atomic weapons, supernova, <i>etc.</i>) in all realms. This limit is probably the result of a balance between the energy flow through a system, resulting in increased temperature and pressure, and the strength of the system’s structure and boundary. ERD has been proposed as a metric for the development of the complexity of dissipative systems over deep time Chaisson (Cosmic evolution; The rise of complexity in nature. Harvard University Press, Cambridge, 2002), Chaisson (Sci World J 384912, 2014). Thus, the observed ERD threshold of 10⁵ W/kg may correspond to a maximum of complexity. Several ways to further increase complexity while circumventing this ERD limit are proposed.</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":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579439","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":"Spinor Boltzmann equation with Berry curvature","authors":"Xiao-Tong Xu,&nbsp;Ya-Ru Wang,&nbsp;Chao Yang,&nbsp;Zheng-Chuan Wang","doi":"10.1140/epjb/s10051-024-00811-3","DOIUrl":"10.1140/epjb/s10051-024-00811-3","url":null,"abstract":"<p>In this paper, we study the influence of Berry curvature on spin-dependent transport in the system with spin-orbit coupling. The interaction of spin-orbit coupling in ferromagnets will induce a non-zero Berry curvature by breaking the time-reversal symmetry, which has effect on both charge and spin transport processes. We introduce the Berry curvature into spinor Boltzmann equation by modifying the effective velocity of electron, then derive the Berry curvature-concerned expressions for spin accumulation, spin current, and charge current, and investigate the influence of Berry curvature on the transport process. Comparisons are also made with the spinor Boltzmann equations which includes Rashba spin-orbit coupling but without Berry curvature.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579507","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":"Investigation of electrophysical and photoelectric properties of solid solution alloys (CdSe)1–x(As2S3)x depending on composition","authors":"I. I. Aliyev,&nbsp;R. M. Rzayev,&nbsp;Kh. M. Gashimov,&nbsp;C. A. Ahmedova,&nbsp;Y. I. Aliyev,&nbsp;A. Y. Huseynova","doi":"10.1140/epjb/s10051-024-00813-1","DOIUrl":"10.1140/epjb/s10051-024-00813-1","url":null,"abstract":"<div><p>The study of renewable energy sources is currently an urgent problem. Such materials are produced by constructing phase diagrams or by cation–anionic substitution of an existing material. From this point of view, the formation of a solid solution (CdSe)_1–<i>x</i>(As₂S₃)x can be due to anionic substitution, which is capable of creating functional properties. In this regard, differential thermal analysis (DTA), X-ray diffraction (XRD), microstructural analysis (MSA), as well as measurements of microhardness and density were performed on solid solutions (CdSe)_1–<i>x</i>(As₂S₃)_<i>x</i>. The nature of the chemical interaction of CdSe with As₂S₃ was studied and it was established that the introduction of As₂S₃ into the composition of CdSe leads to the formation of solid solutions. Moreover, it has been found that solid solutions are formed up to 3 mol% concentration of As₂S₃. The temperature dependence of the electrical conductivity and thermo-EMF of (CdSe)_1–<i>x</i>(As₂S₃)_<i>x</i> (x = 0.01; 0.02; 0.03) solid solutions has been studied. It has been established that the obtained alloys of the solid solution (CdSe)_1–<i>x</i>(As₂S₃)_<i>x</i> (x = (x = 0.01; 0.02; 0.03) are semiconductors of medium resistance. When introducing high-resistance samples of 1; 2 and 3 mol. % As₂S₃ into the composition of CdSe, the specific resistance of the alloys increases depending on the composition, and the conductivity decreases accordingly. For alloys of solid solutions (CdSe)_1–<i>x</i>(As₂S₃)_<i>x</i>, in the composition of 0.3; 0.6; 0.8 and 1.0 mol % As₂S₃, the spectral distribution of the photocurrent was studied. Samples containing 0.3; 0.6; 0.8 and 1.0 mol% As₂S₃ are photosensitive materials capable of operating in the wavelength range of 0.4–1.1 μm.</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":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142565982","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":"Electron correlation and magnetic field induced phase transitions in spin-1/2 Falicov–Kimball model on a triangular lattice","authors":"Swati Pandey,&nbsp;Umesh K. Yadav,&nbsp;Pradip K. Priya","doi":"10.1140/epjb/s10051-024-00812-2","DOIUrl":"10.1140/epjb/s10051-024-00812-2","url":null,"abstract":"<p>We have studied the ground state properties of spin-1/2 Falicov–Kimball model on a triangular lattice in the presence of external magnetic field. Numerical and Monte Carlo simulation methods are employed to obtain the results. We have found that the ground state properties are significantly influenced by the onsite Coulomb correlation between itinerant and localized electrons as well as the orbital magnetic field. Only rational flux fractions are taken into consideration in each unit cell. Transition from metal to insulator phase is accompanied by phase segregation to regular/quasi-regular/mixed phase with change in magnetic field for small values of onsite Coulomb correlation. The external magnetic field facilitates metal to insulator transition even at large values of onsite Coulomb correlation with variation in the number of electrons in the system. The results obtained through this study are applicable to layered triangular lattice systems such as rare earth and transition metal dichalcogenides, cobaltates, <span>(GdI_{2})</span>, <span>(NaTiO_{2})</span>, <span>(NaVO_{2})</span> etc. Further, electric and magnetic sensors and high-energy storage devices can be developed using these results.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"97 11","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142565929","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}