Results in Physics最新文献

{"title":"Identifying excited-state quantum phase transition in a spinor Bose–Einstein condensate with out-of-time-order correlators","authors":"Junjie Zhao ,&nbsp;Xingdong Zhao ,&nbsp;Qi Wang ,&nbsp;Jingxue Liu ,&nbsp;Yingying Zhang ,&nbsp;Lu Qin ,&nbsp;Jieli Qin ,&nbsp;Renfei Zheng ,&nbsp;Lu Zhou","doi":"10.1016/j.rinp.2025.108181","DOIUrl":"10.1016/j.rinp.2025.108181","url":null,"abstract":"<div><div>Out-of-Time-Order Correlator (OTOC) provides a way of quantifying information scrambling in quantum many-body systems and receives increasing attention from different fields. We extend the application of the OTOC to probe the excited-state quantum phase transitions (ESQPT) in spinor Bose–Einstein condensate in an external magnetic field. Using the quantum approach, mean-field theory, and numerical simulations, we have obtained the phase transition points and dynamical properties around them, and have demonstrated that these features can be detected by the OTOC. Our further investigations reveal that the detection efficiency is guaranteed under different magnetization conditions. Our results provide theoretical suggestions for using the OTOCs for experimentally accessing ESQPT in spinor quantum gases and other quantum many-body systems.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108181"},"PeriodicalIF":4.4,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619086","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":"Impact of external pressure and nanoparticles on heat transfer in couple stress Oldroyd-B fluid: A numerical study","authors":"Ayesha Tayyaba ,&nbsp;M.S. Anwar ,&nbsp;Ayesha Jamil ,&nbsp;Taseer Muhammad ,&nbsp;Mumtaz Khan","doi":"10.1016/j.rinp.2025.108173","DOIUrl":"10.1016/j.rinp.2025.108173","url":null,"abstract":"<div><div>This study investigates the flow characteristics of an Oldroyd-B Couple Stress Fluid (OBCSF) under external pressure within the framework of the Buongiorno model. Understanding this dynamic behavior is crucial for advancements in nanofluid technology and non-Newtonian fluid mechanics. The complex behavior of non-Newtonian fluids arises from internal microstructural effects, which are well described by the Oldroyd-B model. The additional influence of external pressure and nanoparticle effects further complicates the flow dynamics, necessitating a comprehensive numerical analysis to understand their combined impact. The governing equations for continuity, momentum, heat transfer, and concentration are formulated and solved numerically under appropriate boundary conditions for the coupled Oldroyd-B fluid and Buongiorno model. A numerical approach integrating the finite difference and finite element methods is employed to analyze the system under varying external pressure conditions and different nanoparticle volume fractions. The numerical simulations reveal significant variations in velocity profiles, temperature distribution, and concentration due to changes in external pressure. The presence of nanoparticles alters viscosity and thermal conductivity, thereby influencing heat transfer within the fluid. Furthermore, the couple stress parameter introduces additional complexity, exhibiting shear-thinning or shear-thickening behavior depending on its magnitude, which in turn affects the overall flow characteristics. These findings underscore the intricate interplay between external pressure, nanoparticle dynamics, and the non-Newtonian properties of the fluid. The study has practical implications for optimizing heat transfer processes in nanofluid-based systems and enhancing the efficiency of industrial applications involving complex fluid dynamics. The insights gained from this research contribute to the design and improvement of technologies that rely on nanofluid mechanics and the distinctive properties of non-Newtonian fluids.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108173"},"PeriodicalIF":4.4,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579796","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":"Thermal performance analysis of quaternary hybrid nanofluids with radiative and Joule heating effects in magnetohydrodynamic flow over a stretched surface","authors":"Faisal Mumtaz ,&nbsp;A. Al-Zubaidi ,&nbsp;Tasawar Abbas ,&nbsp;S. Saleem","doi":"10.1016/j.rinp.2025.108176","DOIUrl":"10.1016/j.rinp.2025.108176","url":null,"abstract":"<div><div>In this study, the thermal behavior of hybrid nanofluids (HNFs) composed of aluminum (<span><math><mrow><mi>A</mi><msub><mi>l</mi><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span>), titanium (<span><math><mrow><mi>Ti</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>), copper (<span><math><mrow><mi>Cu</mi></mrow></math></span>), and silver (<span><math><mrow><mi>Ag</mi></mrow></math></span>) nanoparticles dispersed in water. Hybrid nanofluids are considered for<!--> <!-->two-dimensional<!--> <!-->unsteady flow over porous stretched sheets under the influence of an inclined magnetic field and a non-uniform heat source/sink. The governing partial differential equations (PDEs) are transformed into a set of ordinary differential equations (ODEs), using appropriate transformation. These ODEs are then solved numerically to obtain the desired results. The solution procedure is carried out using numerical simulations, specifically the shooting method and the 4th-order Runge-Kutta (Rk-4) technique. The results are graphically presented to demonstrate the effect of various parameters on heat transfer and velocity profiles. A key objective of this study is to contrast the numerical results with previous results in the literature. The analysis shows that changes in the inclination angle of the magnetic field lead to a decrease in the velocity profile. Moreover, the presence of a heat source significantly enhances the temperature of the nanofluid (NF), with variations in wall shear stress, the Nusselt number, and heat transfer rate reveal important physical insights into the system’s behavior. This investigation supports to a deeper understanding of the thermodynamics of hybrid nanofluids, offering potential for optimization in thermal management and other engineering applications.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108176"},"PeriodicalIF":4.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592922","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":"Effect of oceanic turbulence on the statistical features of electromagnetic optical beam","authors":"Hemant Kumar Singh ,&nbsp;Vikram Singh Bhandari ,&nbsp;Bhaskar Kanseri","doi":"10.1016/j.rinp.2025.108178","DOIUrl":"10.1016/j.rinp.2025.108178","url":null,"abstract":"<div><div>This work deals with the intricate problem of electromagnetic optical beam propagation through oceanic turbulence. Using the extended Huygens–Fresnel principle, numerically, the behavior of the degree of cross-polarization (DOCP), electromagnetic degree of coherence (EMDOC), and also the newly introduced Stokes scintillation parameters are explored through the oceanic turbulence medium. In contrast to atmospheric turbulence, oceanic turbulence introduces complexity in optical beam propagation due to additional variables, such as temperature-salinity fluctuations, the energy dissipation rate, etc. We investigate the fact that during propagation through oceanic turbulence, these parameters are affected differently. The outcomes reveal that changing the coherence and polarization of the input source allows control over these parameters during propagation through oceanic turbulence. Furthermore, we observed that the oceanic turbulence factors, such as temperature fluctuations, rate of dissipation of energy, etc., significantly impact the statistical properties of the vectorial light beams. The implications of these findings are relevant in underwater communication, imaging, remote sensing, and other related applications.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108178"},"PeriodicalIF":4.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579795","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":"Machine learning algorithms for predicting the photoionization cross section of CdS/ZnSe core/shell spherical quantum dots surrounded by dielectric matrices","authors":"A. Cherni ,&nbsp;N. Zeiri ,&nbsp;N. Yahyaoui ,&nbsp;P. Baser ,&nbsp;M. Said ,&nbsp;S. Saadaoui ,&nbsp;Mohammad N. Murshed","doi":"10.1016/j.rinp.2025.108186","DOIUrl":"10.1016/j.rinp.2025.108186","url":null,"abstract":"<div><div>In this study, we explore the prediction of the photoionization cross section (PCS) of CdS/ZnSe core/shell spherical quantum dots (CSQD) surrounded by different dielectric matrices. The quantum dot systems, embedded in polyvinyl alcohol (PVA), polyvinyl chloride (PVC), and silicon dioxide (SiO₂) matrices, were modeled under varying core-shell dimensions and dielectric environments. Our findings show that the resonant peak of the PCS experience a redshift with improvement in their amplitude in the case of the PVA matrix, while in the case of the PVC and SiO_2, the magnitude of the PCS is reduced and their resonant peak suffers a blueshift. Three different machine learning algorithms were used to estimate the photoionization cross-section, namely Artificial Neural Networks (ANN), Decision Trees (DT), and Random Forest Regressors (RFR). Among these, Random Forest Regression proved to be the most successful algorithm, particularly for the SiO₂ matrix, achieving exceptional performance with the coefficient of determination <span><math><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup></math></span> = 0.999 Mean Squared Error <span><math><mrow><mfenced><mrow><mi>M</mi><mi>S</mi><mi>E</mi></mrow></mfenced><mo>=</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>-</mo><mn>4</mn></mrow></msup></mrow></math></span> and the Root Mean Squared Error <span><math><mrow><mfenced><mrow><mi>R</mi><mi>M</mi><mi>S</mi><mi>E</mi></mrow></mfenced><mo>=</mo><mn>0.0077</mn></mrow></math></span>. While DT exhibited lower MSE, MAE, and RMSE than ANN in the SiO₂ matrix, ANN showed potential in capturing more complex nonlinear relationships. These results demonstrate the superior predictive capabilities of RFR and highlight the applicability of machine learning in modeling quantum dot systems. This work offers valuable insights into the optimization of optoelectronic device design through accurate and efficient computational methods.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108186"},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563370","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":"Nano polishing of a rough quartz surface: Numerical calculation of surface evolution","authors":"Vasyl Kanevskii ,&nbsp;Serhii Kolienov ,&nbsp;Valerii Grygoruk ,&nbsp;Ivan Voiteshenko ,&nbsp;Oleksandr Stelmakh ,&nbsp;Yue Wu ,&nbsp;Hao Zhang","doi":"10.1016/j.rinp.2025.108187","DOIUrl":"10.1016/j.rinp.2025.108187","url":null,"abstract":"<div><div>A numerical 3D model of nano-local photochemical etching for polishing a rough quartz surface has been developed. This surface is illuminated from the quartz side at the critical angle of total internal reflection. The light source is a laser coherent monochromatic radiation with linear polarization, and the electric field strength vector lies in the plane of light incidence. The model uses a numerical solution of the Helmholtz equation using the finite elements method. The proposed model allows to describe the evolution of etching of a rough surface and obtain a subnano-meter level of surface roughness. The results of calculation show that the use of two independent sources of linearly polarized laser radiation provides the required level of surface roughness and increases the efficiency of the model compared to direct illumination.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108187"},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579794","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":"General rogue wave solutions and their dynamics in the complex modified Korteweg–de Vries equation","authors":"Yan Zhu ,&nbsp;Lijuan Qin ,&nbsp;Zhiqiang Yang ,&nbsp;Zhenting Chen ,&nbsp;Zhenyun Qin ,&nbsp;Gui Mu","doi":"10.1016/j.rinp.2025.108174","DOIUrl":"10.1016/j.rinp.2025.108174","url":null,"abstract":"<div><div>By means of the Hirota bilinear method together with the Kadomtsev–Petviashvili hierarchy reduction technique, general higher-order rogue wave solutions of the complex modified Korteweg–de Vries equation are derived explicitly. These solutions are expressed succinctly in terms of Gram determinants whose matrix elements are Schur polynomials. It is found that the highest peak amplitude of <span><math><mi>N</mi></math></span>th-order rogue waves turns out to be <span><math><mrow><mn>2</mn><mi>N</mi><mo>+</mo><mn>1</mn></mrow></math></span> times its background amplitude. The <span><math><mi>N</mi></math></span>th-order rogue wave solutions contain the <span><math><mrow><mi>N</mi><mo>−</mo><mn>1</mn></mrow></math></span> irreducible complex parameters. By selecting different values of these free parameters, the rich dynamic behaviors of rogue wave solutions of the complex modified Korteweg–de Vries equation are discovered.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"71 ","pages":"Article 108174"},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143535102","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":"Improved tunnel magnetoresistance by double-barrier magnetic tunnel junctions with a layered antiferromagnet material","authors":"Nader Ghobadi ,&nbsp;Reza Daqiq ,&nbsp;Seyed Ali Hosseini Moradi","doi":"10.1016/j.rinp.2025.108171","DOIUrl":"10.1016/j.rinp.2025.108171","url":null,"abstract":"<div><div>The angle-dependent tunnel magnetoresistance (TMR) is studied in double-barrier magnetic tunnel junctions with a central layered antiferromagnet (DB-MTJs-AF). The study utilizes a tight-binding model to compute the transmission function via the non-equilibrium Green’s function method, incorporating Rashba spin–orbit coupling within the layered AF. The results indicate that DB-MTJs-AF exhibit higher TMR compared to those with a central ferromagnet (DB-MTJs-F). This enhancement is attributed to the unique properties of antiferromagnetic materials leading to improved performance in spintronic devices.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"70 ","pages":"Article 108171"},"PeriodicalIF":4.4,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508523","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":"Effect of Ni-doping on the electronic bandgap and thermal conductivity of calcium hydroxide: Experimental and theoretical investigation","authors":"Basit Ali,&nbsp;Aamir Khan,&nbsp;Faheem Amin","doi":"10.1016/j.rinp.2025.108177","DOIUrl":"10.1016/j.rinp.2025.108177","url":null,"abstract":"<div><div>In the current research work, pure and nickel-doped calcium hydroxide (Ni-doped Ca(OH)₂) were studied both experimentally and theoretically. Theoretically, the material is examined by using the full-potential linearized augmented plane wave (FP-LAPW) scheme as implemented in the WIEN2K Simulation package. Experimentally, the pure and Ni-doped Ca(OH)₂ were prepared via a simple inexpensive chemical method. The structural, thermal, electronic, and optical behavior of doped and pure Ca(OH)₂ were analyzed. The addition of nickel increased the experimental thermal conductivity from 0.0942 to 0.2063 W/mK. The experimental band gap energy was determined to reduce from 5.21 eV to 4.04 eV for pure and Ni-doped Ca(OH)₂ respectively. The Ni-doped Ca(OH)₂ sample shows an increasing trend of optical properties in the visible region by incorporating Ni⁺² ions. This research work shows that Ni-doped Ca(OH)₂ is a favorable competitor for enhanced thermoelectric and optoelectronic applications.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"70 ","pages":"Article 108177"},"PeriodicalIF":4.4,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512260","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":"On new regular quadratic Gaussian black hole: Photon sphere, shadow and gravitational lensing","authors":"K. Ghaderi ,&nbsp;B. Malekolkalami ,&nbsp;Anirudh Pradhan ,&nbsp;Archana Dixit","doi":"10.1016/j.rinp.2025.108168","DOIUrl":"10.1016/j.rinp.2025.108168","url":null,"abstract":"<div><div>Gaussian black holes constitute an important class of regular black holes, characterized by their spherically symmetric and static nature. These solutions emerge from the framework of Einstein’s equations, particularly when incorporating the effects of the cosmological constant, which plays a crucial role in the overall dynamics of the universe. By examining the null geodesics, we have sought to elucidate the form of the shadow generated by an innovative regular pure quadratic Gaussian black hole. This study contributes to the broader discourse on black hole physics and the implications of their unique structures on observable phenomena. A comprehensive study has been undertaken to explore the relationship between black hole shadows and the configuration of the event horizon, focusing on the impact of Gaussian distribution and black hole mass. The findings of this research contribute to a more nuanced comprehension of how these variables influence the properties of the horizon, the photon sphere, and the effective potential associated with black holes. In addition, our study delves into the effects of gravitational lensing produced by a quadratic Gaussian black hole. The findings demonstrate how variations in the black hole’s parameters can alter several observable characteristics associated with the gravitational lensing effect.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"70 ","pages":"Article 108168"},"PeriodicalIF":4.4,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143527277","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}