Brazilian Journal of Physics最新文献

Effect of Electron Spin Polarization on Laser-Assisted Semirelativistic Excitation of Atomic Hydrogen from the Metastable 2s State to the 4s State in a Circularly Polarized Laser Field 圆偏振激光场中电子自旋极化对氢原子从亚稳态2s态到4s态激光辅助半相对论性激发的影响

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-14 DOI: 10.1007/s13538-026-02162-z

C. Hajjaj, M. Ouali, S. Taj, B. Manaut, M. El Idrissi

{"title":"Effect of Electron Spin Polarization on Laser-Assisted Semirelativistic Excitation of Atomic Hydrogen from the Metastable 2s State to the 4s State in a Circularly Polarized Laser Field","authors":"C. Hajjaj, M. Ouali, S. Taj, B. Manaut, M. El Idrissi","doi":"10.1007/s13538-026-02162-z","DOIUrl":"10.1007/s13538-026-02162-z","url":null,"abstract":"<div>This paper presents a semirelativistic theoretical study of a laser-assisted inelastic electron-atom scattering. Specifically, we investigate the laser-assisted excitation of atomic hydrogen from the metastable 2s state to the 4s state, induced by electron impact with particular emphasis upon spin-dependent effects. The analysis is carried out within the framework of the first Born approximation, while the interaction of the incident and scattered electrons with the laser field is described using Dirac–Volkov states. An analytical expression for the spin-unpolarized differential cross section is derived, providing a reference for assessing the consistency and reliability of the adopted theoretical approach. In addition, the spin-flip and spin–non-flip differential cross sections are investigated. The numerical results show that the spin-flip contribution is negligible compared with the spin–non-flip contribution over the range of parameters considered, indicating that spin-conserving transitions dominate the excitation process.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189380","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}

引用次数: 0

A DFT Study on the Influence of Sulfur Vacancy and Oxygen Doping on Bandgap Engineering of 2H WS2 Nanolayers 硫空位和氧掺杂对2H WS2纳米层带隙工程影响的DFT研究

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-14 DOI: 10.1007/s13538-026-02165-w

B. Bhattacharjee, G. Pradhan

{"title":"A DFT Study on the Influence of Sulfur Vacancy and Oxygen Doping on Bandgap Engineering of 2H WS2 Nanolayers","authors":"B. Bhattacharjee, G. Pradhan","doi":"10.1007/s13538-026-02165-w","DOIUrl":"10.1007/s13538-026-02165-w","url":null,"abstract":"<div>This study is an extension of our experimental work on synthesis of WS2 nanolayers; by varying laser energy in pulsed laser deposition, indicating sulfur deficient nanolayers. Hence, we further investigated the influence of number and different vacancy configurations within the non-periodic supercell, appearing to be at the edge or at the center, of sulfur vacancy (SV) and oxygen doping (OD), on the band structure, bandgap and density of states of the monolayers (ML) and bilayers (BL) of 2 H WS2 polymorph, using Density functional theory. The (001) slab model of the WS2 ML & BL was made with an array of 3 × 3 × 1 and 3 × 3 × 2 supercells, respectively. The number of SV & OD was varied from 1 to 3 and 1 to 2, respectively. For edge appearing SV WS2 ML, the bandgap narrows rapidly with increase of SV and closes for 3 SV; having S/W ratio of 1.66. For center appearing SV, the bandgap also narrows slowly with increase of SV and remains slightly open for 3 SV. In WS2 BL, the bandgap remains open for edge and center appearing 3 SV. The 1 O atom (5.55% doping) doped pristine ML, shows 0.5% to 1.99% bandgap opening, as compared to pristine ML. The 2 O atom (11.11%) doped pristine ML, shows 5.5% to 9.95% bandgap narrowing. This work indicates the feasibility of the bandgap engineering of WS2 nanolayers by controlled SV and O doping.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189379","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}

引用次数: 0

Reaction Dynamics of the Unstable 7Be Nucleus in the Field of 9Be, 28Si, and 58Ni Targets at Near-Barrier Energies 近势垒能9Be、28Si和58Ni靶场中不稳定7Be核的反应动力学

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-14 DOI: 10.1007/s13538-026-02163-y

D. S. Valiolda, D. M. Janseitov, S. K. Sakhiyev, D. Alimov, Awad A. Ibraheem, Sh. Hamada

{"title":"Reaction Dynamics of the Unstable 7Be Nucleus in the Field of 9Be, 28Si, and 58Ni Targets at Near-Barrier Energies","authors":"D. S. Valiolda, D. M. Janseitov, S. K. Sakhiyev, D. Alimov, Awad A. Ibraheem, Sh. Hamada","doi":"10.1007/s13538-026-02163-y","DOIUrl":"10.1007/s13538-026-02163-y","url":null,"abstract":"<div>This study investigates the elastic scattering of 7Be nuclei on 9Be, 28Si, and 58Ni targets at laboratory energies near the Coulomb barrier. The analysis was conducted using two complementary theoretical frameworks: the Optical Model (OM) and the Continuum-Discretized Coupled-Channels (CDCC) method. Within the OM, a microscopic bare potential was generated using the São Paulo potential to define both the real and imaginary nuclear components. Two fitting approaches were adopted: a one-parameter approach (SPP2-I) with the real part fixed at its theoretical value, and a two-parameter approach (SPP2-II) with both real and imaginary strengths allowed to vary. The CDCC approach explicitly incorporated the 3He + 4He cluster configuration of 7Be, allowing for couplings between the elastic channel and the breakup continuum. The research focuses on two unresolved questions: the potential manifestation of the breakup threshold anomaly in 7Be-induced reactions, and the magnitude of the continuum coupling effects on the elastic scattering observables.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189382","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}

引用次数: 0

Entanglement Recovering Under Local Non-Positive Reduced Dynamics 局部非正约简动力学下纠缠恢复

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-12 DOI: 10.1007/s13538-026-02153-0

Iman Sargolzahi

{"title":"Entanglement Recovering Under Local Non-Positive Reduced Dynamics","authors":"Iman Sargolzahi","doi":"10.1007/s13538-026-02153-0","DOIUrl":"10.1007/s13538-026-02153-0","url":null,"abstract":"<div>Consider a bipartite quantum system (S=AB) such that each part interacts only with its local environment. Under such circumstances, one expects that the entanglement between parts A and B does not increase after the time evolution. In fact, this is the case if the reduced dynamics of the system is given by (mathcal {E}_{A}otimes mathcal {E}_{B}), where (mathcal {E}_{A}) and (mathcal {E}_{B}) are quantum channels, i.e., completely positive trace-preserving maps. But, the reduced dynamics of the system may be given by a map as (Psi _{A}otimes Psi _{B}), where (Psi _{A}) and (Psi _{B}) are local non-positive maps. Then, the entanglement between A and B can exceed its initial value, as was shown in the case studied by Jordan et al. [ Phys. Rev. A 76, 022102 (2007)]. In this paper, we first explore the general circumstances under which one can find such cases as they found. Next, we introduce another general procedure which leads to local non-positive maps that exhibit entanglement exceeding. Furthermore, we demonstrate that this apparent entanglement increase in the two above procedures corresponds physically to the retrieval of pre-existing inaccessible entanglement stored across the global system-environment degrees of freedom, rather than genuine generation of the entanglement ex nihilo.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189244","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}

引用次数: 0

Weak Cosmic Censorship in Einstein-Born-Infeld Black Hole: A Parameter-Space Analysis 爱因斯坦-因菲尔德黑洞的弱宇宙审查：一个参数空间分析

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-12 DOI: 10.1007/s13538-026-02158-9

M. L. Peñafiel, F. T. Falciano, J. C. Fabris

引用次数: 0

Experimental Cross Section of the 176Lu(n,γ)177Lu Reaction at the Neutron Energy of 3.626 meV Using NUR Reactor Reflectometer 中子能量为3.626 meV时176Lu(n,γ)177Lu反应的实验截面

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-12 DOI: 10.1007/s13538-026-02167-8

Naima Belouadah, Tarik Seguini, Nadjet Osmani, Tarek Azli, Sofiane Benbouzid, Liela Yettou, Imane Trabelsi

{"title":"Experimental Cross Section of the 176Lu(n,γ)177Lu Reaction at the Neutron Energy of 3.626 meV Using NUR Reactor Reflectometer","authors":"Naima Belouadah, Tarik Seguini, Nadjet Osmani, Tarek Azli, Sofiane Benbouzid, Liela Yettou, Imane Trabelsi","doi":"10.1007/s13538-026-02167-8","DOIUrl":"10.1007/s13538-026-02167-8","url":null,"abstract":"<div>The reflectometry technique in NUR Research Reactor of Algeria was used for the measurement the neutron capture cross section for the 176Lu(n,γ)177Lu reaction at 3.626 meV energy. The Neutron Activation Analysis (NAA) technique using 197Au(n,γ)198Au as reference reaction was adopted. The. γ-ray spectra measurements were made for the Germanium Hyper Pure for the Lu2O3. This experiment is the first time at this energy. A resulting value of σ (3827 ± 191) b was measured for the neutron cross section after correction for neutron self-shielding and γ attenuation effects. The measured value was then compared to the evaluated cross sections reported in two different libraries of neutron databases ENDF/B-VIII.1 and JEFF-4.0. The extrapolated for the neutron capture cross section 176Lu(n,γ)177Lu reaction at 0.0253 eV was compared with evaluated and experimental data. A scarcity of experimental data at 0.0253 eV limits the possibility of conducting a comprehensive comparison with the available results.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189422","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}

引用次数: 0

Universal Scaling and Relaxation in Decaying Turbulence of Bose Gases 玻色气体衰变湍流中的普遍标度和弛豫

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-10 DOI: 10.1007/s13538-026-02155-y

Arnol D. García-Orozco, Michelle A. Moreno-Armijos, Sarah Sab, Amilson Fritsch, Vanderlei S. Bagnato

{"title":"Universal Scaling and Relaxation in Decaying Turbulence of Bose Gases","authors":"Arnol D. García-Orozco, Michelle A. Moreno-Armijos, Sarah Sab, Amilson Fritsch, Vanderlei S. Bagnato","doi":"10.1007/s13538-026-02155-y","DOIUrl":"10.1007/s13538-026-02155-y","url":null,"abstract":"<div>Understanding the relaxation dynamics of isolated quantum systems remains a central challenge in nonequilibrium physics. In this short review, we discuss recent experimental and theoretical advances in universal dynamics of turbulent Bose gases, with particular emphasis on nonthermal fixed points and wave turbulence in our experimental system at the São Carlos Institute of Physics of the University of São Paulo. We highlight the emergence of self-similar scaling behavior and its connection to particle and energy transport across momentum scales. In addition, we discuss an approach in which a differential equation has a universal scaling solution, providing a practical framework for extracting universal exponents from limited regions of the momentum distribution. Furthermore, we recap experimental observations of direct and inverse cascades in a three–dimensional trapped Bose–Einstein condensate, revealing distinct relaxation stages governed by universal scaling laws. These results demonstrate that turbulence plays a key role in far–from–equilibrium dynamics, offering a unified perspective on transport processes and thermalization in quantum many–body systems.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-026-02155-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189403","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}

引用次数: 0

Role of Resonances in Total, Coulomb, and Nuclear Breakup Cross Sections for Light and Heavy Targets 共振在重、轻靶的总、库仑和核破裂截面中的作用

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-09 DOI: 10.1007/s13538-026-02164-x

Lucas Vusi Ndala, Mantile Leslie Lekala

{"title":"Role of Resonances in Total, Coulomb, and Nuclear Breakup Cross Sections for Light and Heavy Targets","authors":"Lucas Vusi Ndala, Mantile Leslie Lekala","doi":"10.1007/s13538-026-02164-x","DOIUrl":"10.1007/s13538-026-02164-x","url":null,"abstract":"<div>The influence of resonances on the breakup dynamics of the ({^6})Li+(^{58})Ni and ({^6})Li+(^{208})Pb systems is investigated using the continuum discretized coupled-channels (CDCC) method at incident energies above the Coulomb barrier. The calculated elastic scattering angular distributions are found to reproduce the available experimental data for both systems. The effects of resonances on the total, Coulomb, and nuclear breakup cross sections are analyzed as functions of scattering angle and incident energy. For the ({^6})Li+(^{58})Ni system, non-resonant breakup contributions dominate the nuclear and total breakup cross sections, while resonance effects remain relatively weak. In contrast, resonant breakup cross section plays a significant role in the ({^6})Li+(^{208})Pb reaction, particularly in the Coulomb breakup cross section. The results show that the influence of resonances decreases with increasing incident energy, indicating the growing importance of non-resonant continuum couplings at higher energies. The dependence of breakup observables on dipole, quadrupole, and octupole couplings is also investigated, revealing a pronounced sensitivity to the multipolarity of the coupling. These findings demonstrate that the importance of resonant and non-resonant breakup mechanisms depends strongly on the target mass and incident energy.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-026-02164-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132785","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}

引用次数: 0

Critical Behavior in Ga-doped van der Waals Magnet CrI3 掺ga范德华磁体CrI3的临界行为

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-09 DOI: 10.1007/s13538-026-02150-3

Ying Zhang, Yuxuan Miao, Wenqi Gu, Ke Zhang, Ping Liu

引用次数: 0

Evaluating the Stability of 2D Compounds: Effects of Temperature, Mechanical Support and Vibrational Degrees of Freedom 评价二维化合物的稳定性：温度、机械支撑和振动自由度的影响

IF 1.8 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2026-10-09 DOI: 10.1007/s13538-026-02160-1

Lucas Martin Farigliano, Fabio Negreiros Ribeiro, Gustavo Martini Dalpian

{"title":"Evaluating the Stability of 2D Compounds: Effects of Temperature, Mechanical Support and Vibrational Degrees of Freedom","authors":"Lucas Martin Farigliano, Fabio Negreiros Ribeiro, Gustavo Martini Dalpian","doi":"10.1007/s13538-026-02160-1","DOIUrl":"10.1007/s13538-026-02160-1","url":null,"abstract":"<div>The thermodynamic stability of two-dimensional (2D) materials remains a critical bottleneck in their synthesis and practical application. While Density Functional Theory (DFT) has revolutionized the characterization of these systems, standard 0 K computational protocols often overlook the complex interplay between thermal fluctuations and structural constraints. In this work, we investigate the stability of 2D MgO monolayers, examining how temperature, structural flexibility and mechanical support from a Pd substrate influence the material’s energy landscape. Our findings show that the thermodynamic behavior depends strongly on the structural degrees of freedom accessible in the simulations. Adequately large simulation cells are required to capture long-wavelength vibrational modes that significantly lower the free energy through entropic contributions. We demonstrate that while freestanding monolayers become unstable at finite temperatures, mechanical coupling with a substrate provides a crucial stabilizing effect while modifying the electronic band gap and atomic mobility. These results provide a more accurate framework for predicting the behavior of 2D compounds under realistic experimental conditions and highlight the importance of including vibrational entropy and substrate effects in computational studies of two-dimensional materials.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"56 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-026-02160-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132778","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}

引用次数: 0