The European Physical Journal B最新文献

{"title":"Quantum chemical exploration of piperazinium nitrate: molecular stability, reactivity descriptors, electronic excitations, intermolecular interactions, and NLO activity","authors":"V. Vijayalakshmi,&nbsp;G. Suresh,&nbsp;S. Selvakumari,&nbsp;V. Ragavendran,&nbsp;J. Janczak,&nbsp;N. Kanagathara","doi":"10.1140/epjb/s10051-025-01106-x","DOIUrl":"10.1140/epjb/s10051-025-01106-x","url":null,"abstract":"<div><p>Single crystals of Piperazinium Nitrate were obtained by slow evaporation, crystallizing in a monoclinic system (P2₁/<i>c</i>), and stabilized by strong N–H···O hydrogen bonds in a three-dimensional network. structural integrity of the grown crystal was confirmed by X-ray diffraction (XRD) analysis. Experimental characterization using FT–IR and FT–Raman spectroscopy confirmed the presence of functional groups and characteristic vibrational modes corresponding to the molecular structure. Hirshfeld surface (HS) analysis and 2D fingerprint plots quantified the intermolecular contacts, highlighting the dominant role of hydrogen bonding in crystal packing and structural stability. HS analysis revealed that O···H interactions contribute 54.9% of the overall intermolecular contacts, confirming the dominance of hydrogen bonding in the crystal packing. Density Functional Theory (DFT) calculations at the B3LYP/6-311G (d, p) level were performed to optimize the molecular geometry and investigate the electronic structure, revealing a significant HOMO–LUMO energy gap of 5.391 eV, denoting the stability of molecule and low chemical reactivity. Time-Dependent DFT (TD-DFT) simulations of the UV–Visible (UV–Vis) spectrum provided insights into the electronic excitation behavior. The absorption peak at 255.76 nm, it exhibits the π → π* and n → π* electronic transitions in gas phase. Natural Bond Orbital (NBO) analysis indicated a strong intramolecular hyperconjugative interaction between the lone pair on LP(3) O₂ and antibonding orbital of the N1–O4 bond, contributing 144.41 kJ mol⁻¹ to molecular stabilization. Fukui function analysis identified the reactive sites susceptible to electrophilic and nucleophilic attack. Electron Localization Function (ELF) and Localized Orbital Locator (LOL) maps illustrated regions of electron localization and delocalization. Non-Covalent Interaction (NCI) analysis based on Reduced Density Gradient (RDG) plots revealed the presence of weak van der Waals forces and strong hydrogen bonding interactions. The calculated first-order hyperpolarizability (29.244 × 10⁻³¹ esu), which is 7.8 times greater than that of urea, and the calculated first-order hyperpolarizability confirms the strong NLO response and highlights the potential of the compound for nonlinear optical (NLO) and photonic applications.</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":"99 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145909024","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":"Multiple crossover in the decay of metastable volume fraction of a Blume–Capel ferromagnetic needle","authors":"Ishita Tikader,&nbsp;Muktish Acharyya","doi":"10.1140/epjb/s10051-025-01115-w","DOIUrl":"10.1140/epjb/s10051-025-01115-w","url":null,"abstract":"<p>The transient behaviours of a Blume–Capel ferromagnetic needle have been studied extensively by Monte-Carlo simulation. The needle has an elongated length in one direction compared to its cross-section. In the context of transient behaviour, we have captured the decay of the metastable state and the magnetic relaxation behaviours in our study. The dependence of metastable behaviour on anisotropy (single site) has been studied. <i>Interestingly, we have observed multiple</i> (<i>different values of</i> <i>n</i> <i>in different time domains</i>) <i>crossover in the decay of metastable volume fraction</i> (<i>obeying Avrami’s law</i> <span>(beta sim textrm{exp}(-Kt^n))</span>). <i>We have identified the crossover time, and the values of</i> <i>n</i> <i>are estimated precisely.</i> The mean (magnetic) reversal time has been studied as a function of anisotropy. It is observed to be almost independent of anisotropy for its negative value; however, it is found to decrease exponentially with positive anisotropy. The exponential relaxation behaviour (in the corresponding paramagnetic phase) is observed. The relaxation time was found to depend on the strength of anisotropy.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831336","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":"Dynamical quantum phase transitions in the Lipkin–Meshkov–Glick model with longitudinal and transverse magnetic fields","authors":"D. S. Lohr-Robles,&nbsp;M. Grether,&nbsp;E. López-Moreno,&nbsp;P. O. Hess","doi":"10.1140/epjb/s10051-025-01111-0","DOIUrl":"10.1140/epjb/s10051-025-01111-0","url":null,"abstract":"<p>The dynamical properties of the Lipkin–Meshkov–Glick model with longitudinal and transverse fields are studied by considering quantum quenches. The model describes a many-body quantum system with long-range interactions. A semiclassical analysis is performed to obtain the critical points of quantum phase transitions. These critical points consist in the static separatrix, which is found by analyzing the stability structure of the semiclassical potential and is useful in the identification of ground state and excited states quantum phase transitions, and in the dynamical separatrix, which depends on initial conditions and is found by studying the classical equations of motion for the Hamiltonian. The static and dynamical separatrices divide the parameter space in regions of different dynamical behavior, and it is found that both separatrices play an important role in the determination of the occurrences of the dynamical quantum phase transitions.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjb/s10051-025-01111-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831510","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":"Continuous sample space reducing stochastic process","authors":"Rahul Chhimpa,&nbsp;Avinash Chand Yadav","doi":"10.1140/epjb/s10051-025-01112-z","DOIUrl":"10.1140/epjb/s10051-025-01112-z","url":null,"abstract":"<p>We propose a simple model for a sample space reducing (SSR) stochastic process, where the dynamical variable denoting the size of the state space is continuous. In general, one can view the model as a constrained multiplicative stochastic process such that the size of the state space cannot be smaller than a visibility parameter <span>(epsilon .)</span> We study the survival time statistics that reveal a subtle difference from the discrete version of the process. A straightforward generalization can explain the noisy SSR process, characterized by a tunable parameter <span>(lambda in [0, 1].)</span> We also examine the statistics of the size of the state space that follows a power-law distributed probability <span>({mathbb {P}}_{epsilon }(zle epsilon ) sim z^{-alpha },)</span> with a nontrivial value of the exponent as a function of the tunable parameter <span>(alpha = 1+lambda .)</span></p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831447","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":"Artificial intelligence and machine learning for phases and transitions in the Ising model: an overview","authors":"Vasanth Kumar Babu,&nbsp;Rahul Pandit","doi":"10.1140/epjb/s10051-025-01105-y","DOIUrl":"10.1140/epjb/s10051-025-01105-y","url":null,"abstract":"<p>The Ising spin model has long been the foundational model for studying phase transitions in theoretical statistical physics. In the wake of the explosion of machine-learning (ML) techniques in recent years, the Ising model has been used for ML applications to phase transitions. In this overview, we discuss the applications of ML, via both supervised and unsupervised learning, to the study of phases and transitions in the Ising model. We also discuss transfer learning and provide some examples of its use for neural networks trained on Ising model spin configurations. We conclude with a summary and some future directions.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145831420","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":"Enhanced electrochemical performance of Ba-doped CoMoO3 for supercapacitor applications","authors":"Haifa A. Alyousef,&nbsp;Shaimaa A. M. Abdelmohsen,&nbsp;Areej Saleh Alqarny,&nbsp;Najla Alotaibi,&nbsp;Younis Ejaz,&nbsp;Muhammad Imran,&nbsp;Hafiz Muhammd Tahir Farid","doi":"10.1140/epjb/s10051-025-01088-w","DOIUrl":"10.1140/epjb/s10051-025-01088-w","url":null,"abstract":"<div><p>The rapid progress of various renewable energy conversion methods has driven an increasing demand for efficient energy storage systems. Transition metal oxides are widely utilized as electrodes in supercapacitor devices; nonetheless, however, they suffer from significant drawbacks such as limited surface area and inadequate conductivity. Doping has been recognized as an efficient approach to overcome these limitations. This current research utilized a hydrothermal technique to increase the capacitive characteristics of CoMoO₃ by doping with barium ion (Ba²⁺). Several physical studies were utilized to confirm the crystal structure, enhanced morphology and surface area of Ba-doped CoMoO₃, while the physiochemical parameters of doped electrode sample were assessed using several analytical techniques. The examination of energy storage applications included a 3.0 M KOH for performing cyclic voltammetry (CV) studies, galvanic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). Ba-doped CoMoO₃ nanocomposites exhibit significant <i>C</i>_s values of approximately 1001 F/g with <i>E</i>_d of (20.48 Wh/kg) and <i>P</i>_d of (192 W/kg) showcasing superior charge–discharge cyclic performance. The Ba-doped CoMoO₃ electrode material exhibited superior electrochemical properties, rendering it a viable candidate for future supercapacitor devices.</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 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145779028","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":"Finite population dynamics resolve the central paradox of the Inspection Game","authors":"Bianca Y. S. Ishikawa,&nbsp;José F. Fontanari","doi":"10.1140/epjb/s10051-025-01104-z","DOIUrl":"10.1140/epjb/s10051-025-01104-z","url":null,"abstract":"<p>The Inspection Game is the canonical model for the strategic conflict between law enforcement (inspectors) and citizens (potential criminals). Its classical Mixed-Strategy Nash Equilibrium (MSNE) is afflicted by a paradox: the equilibrium crime rate is independent of both the penalty size (<i>p</i>) and the crime gain (<i>g</i>), undermining the efficacy of deterrence policy. We re-examine this challenge using evolutionary game theory, focusing on the long-term fixation probabilities of strategies in finite, asymmetric population sizes subject to demographic noise. The deterministic limit of our model exhibits stable limit cycles around the MSNE, which coincides with the neutral fixed point of the equilibrium analysis. Crucially, in finite populations, demographic noise drives the system away from this cycle and toward absorbing states. Our results demonstrate that high absolute penalties <i>p</i> are highly effective at suppressing crime by influencing the geometry of the deterministic dynamics, which in turn biases the fixation probability toward the criminal extinction absorbing state, thereby restoring the intuitive role of <i>p</i>. Furthermore, we reveal a U-shaped policy landscape where both high penalties and light penalties (where <span>(p approx g)</span>) are successful suppressors, maximizing criminal risk at intermediate penalty levels. Most critically, we analyze the realistic asymptotic limit of extreme population sizes asymmetry, where inspectors are exceedingly rare. In this limit, the system’s dynamic outcome is entirely decoupled from the citizen payoff parameters <i>p</i> and <i>g</i>, and is instead determined by the initial frequency of crime relative to the deterrence threshold (the ratio of inspection cost to reward for catching a criminal). This highlights that effective crime suppression requires managing the interaction between deterministic dynamics, demographic noise, and initial conditions.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145729964","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":"Characterizing the phase transition of anomalous Dicke model via Loschmidt echo and studying different phases in 1D and 2D lattice structures","authors":"Hong-Yu Chen,&nbsp;Bo Li,&nbsp;Dong-Yan Lü,&nbsp;Xu-Wu Wang,&nbsp;Qing-Lan Wang,&nbsp;Ya-Wen Li,&nbsp;Yuan Zhou","doi":"10.1140/epjb/s10051-025-01103-0","DOIUrl":"10.1140/epjb/s10051-025-01103-0","url":null,"abstract":"<p>This paper introduces a theoretical method for characterizing the quantum phase transitions (QPTs) of the anomalous Dicke model (ADM) by employing the Loschmidt echo (LE) to access the photon number variance. The ADM features a normal phase (NP) and two superradiant phases: electric (SEP) and magnetic (SMP), respectively. We further extend the ADM to one-dimensional (1D) chain-like and two-dimensional (2D) square-like lattice structures. Analysis of the energy bands in these lattice models reveals the emergence of unstable phases, which are primarily induced by photon–photon hopping interactions between adjacent cavities, namely the dispersion relation. We map the unstable phases onto the phase diagram and analyze the boundaries between different phases, along with the properties of the energy bands within each phase region. This work provides valuable insights into the applications of QPTs and quantum manipulations through the unconventional Dicke-lattice model.</p>","PeriodicalId":787,"journal":{"name":"The European Physical Journal B","volume":"98 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145730121","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":"Exploring the impact of Ag doping on improving the photocatalytic performance of SnO2 nanoparticles for dye degradation","authors":"E. Jegalakshmi,&nbsp;M. Rameshbabu,&nbsp;P. Sagayaraj,&nbsp;K. Prabha,&nbsp;S. Muthupandi,&nbsp;Manikandan Ayyar,&nbsp;Saravanan Rajendran,&nbsp;M. Santhamoorthy","doi":"10.1140/epjb/s10051-025-01099-7","DOIUrl":"10.1140/epjb/s10051-025-01099-7","url":null,"abstract":"<div><p>Silver-modified tin oxide (SnO₂) nanomaterials with different amounts of additive (1, 3, and 5%) were prepared through a simple co-precipitation method to enhance their efficiency in photocatalytic degradation of methylene blue under UV–visible light irradiation. Structural characterization by X-ray diffraction confirmed the formation of a tetragonal rutile phase of SnO₂ and in addition distinct reflections corresponding to face-centered cubic (FCC) phase of silver were observed upon doping, indicating the development of a dual-phase system comprising SnO₂ and metallic Ag with crystallite sizes ranging from 12 to 24 nm. Fourier-transform infrared spectroscopy confirmed the functional group of the synthesized samples by revealing metal–oxygen bonding and surface hydroxyl groups. UV–Vis spectroscopy revealed a blue shift in the absorption edge and an increase in band gap energy with Ag incorporation, suggesting quantum confinement and reduced defect states. Scanning electron microscopy revealed agglomerated flake-like morphologies, and EDX verified the even distribution of Sn, O, and Ag, supporting compositional purity. Thermal analysis (TGA/DTA/DSC) showed melting point reduction upon increased dopant concentration, supporting the increased thermal stability. Photocatalytic activity under visible light irradiation indicated that the highest degradation efficiency (81.53%) against methylene blue was achieved by 1% Ag-doped SnO₂ due to enhanced charge carrier separation and localized surface plasmon resonance effects at low Ag concentration. These findings illustrate that fine-tuning Ag content is essential in achieving maximum photocatalytic efficiency in environmental remediation technologies.</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 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145675023","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":"Hopf bifurcation analysis and control of traffic flow model based on speed limit and lane change information of networked vehicles","authors":"Wenhuan Ai,&nbsp;Yonghao Yang,&nbsp;Guoao Li,&nbsp;Xin Yang","doi":"10.1140/epjb/s10051-025-01084-0","DOIUrl":"10.1140/epjb/s10051-025-01084-0","url":null,"abstract":"<div><p>Building upon the integration of bifurcation theory from nonlinear dynamics and traffic flow theory, this paper incorporated road speed limit information and lane change behavior provided by intelligent vehicle networks during the driving process. A macroscopic traffic flow model was proposed to address critical challenges in traffic system stability analysis, sudden behavioral transitions, and feedback control design. The equilibrium solutions of the proposed model – considering both speed limits and lane change information – were analyzed using differential equation theory. The dynamic behavior near these equilibrium points was visualized through phase plane diagrams, providing a foundation for subsequent theoretical investigations. Based on this analysis, the existence conditions and types of Hopf bifurcations were derived theoretically, describing how traffic congestion and system stability evolve under varying conditions. The critical point of system mutation was identified and analyzed to explore the mechanism behind global stability changes, providing technical support for preventing and mitigating traffic congestion. Focusing on the unstable dynamics near bifurcation points, a stochastic function was introduced into an improved Full Velocity Difference Model (FVDM) to examine how bifurcation behaviors manifest in traffic flow. A control mechanism was designed to stabilize the system by adjusting its parameters, thereby modifying the existence and amplitude of Hopf bifurcations. This approach effectively suppresses unstable oscillatory behavior, reduces periodic fluctuations in traffic density, and enhances overall traffic flow stability. Finally, simulations involving spatio-temporal density diagrams, phase plane plots, and real-world public traffic datasets were conducted to validate the influence of speed limit and lane change information on driver decision-making. The impact of the feedback controller on system stability was also demonstrated, thereby enabling the optimization of traffic control strategies. The findings contribute to intelligent transportation planning and support future developments in autonomous driving and connected vehicle systems.</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 12","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145675272","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}