IF 2.1 4区物理与天体物理

Pramana Pub Date : 2025-07-08 DOI: 10.1007/s12043-025-02941-4

Vikas Arora, Sukanya Pal, Luminita Harnagea, D V S Muthu, A K Sood

{"title":"Ultrafast dynamics of coherent phonon modes in the excitonic insulator (hbox {Ta}_2hbox {NiSe}_5)","authors":"Vikas Arora, Sukanya Pal, Luminita Harnagea, D V S Muthu, A K Sood","doi":"10.1007/s12043-025-02941-4","DOIUrl":"10.1007/s12043-025-02941-4","url":null,"abstract":"<div><p>The spontaneous condensation of excitons in the excitonic insulating phase has been reported in <span>(hbox {Ta}_2hbox {NiSe}_5)</span> (TNSe) below 325 K. In this context, we present the temperature-dependent optical pump–optical probe spectroscopy of <span>(hbox {Ta}_2hbox {NiSe}_5)</span>, with the focus on coherent phonon (CP) dynamics. In addition to the fast relaxation process involving excitonic recombination, we observe a systematic behaviour for the slow relaxation process associated with the relaxation of hot phonons. The asymmetry parameter and cubic anharmonicity of the 3 THz mode demonstrate the structural transition across <span>(T_C=325)</span> K, whereas the nature of the order parameter and asymmetry of 2 THz modes reveal its coupling with the excitonic phase of TNSe. Coherent phonon modes display less anharmonicity than the corresponding Raman modes. Continuous wavelet transform (CWT) reveals that the peak time <span>(t_{textrm{peak}})</span> of the phonons is similar for all modes except the 3 THz mode. The temperature dependence of <span>(t_{textrm{peak}})</span> for the M3 mode exhibits a possible role of excitonic condensate below <span>(T_C)</span> in the formation of quasiparticle (phonon). CWT analysis supports the time-dependent asymmetry of the M3 mode caused by photoexcited carriers. This study illustrates the role of photoexcited carriers in depicting a structural transition and dressing of coherent phonons, hence, demonstrating many-body effects.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145163476","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

Complex exact optical solutions for the high-dispersive nonlinear Schrödinger equation with parabolic law nonlinearity 具有抛物律非线性的高色散非线性Schrödinger方程的复精确光学解

IF 2.1 4区物理与天体物理

Pramana Pub Date : 2025-07-08 DOI: 10.1007/s12043-025-02939-y

Zilin Wang, Ben Gao

引用次数: 0

Soliton dynamics related to the stochastic Gross–Pitaevskii equation in the presence of random fluctuations 随机波动下与随机Gross-Pitaevskii方程相关的孤子动力学

IF 2.1 4区物理与天体物理

Pramana Pub Date : 2025-07-07 DOI: 10.1007/s12043-025-02957-w

Fiza Batool, Nauman Raza, Iqra Anwar, Mustafa Bayram, Ahmet Bekir

引用次数: 0

An investigation of Eyring–Powell nanofluid across a curved stretching surface with micro-organisms, thermal radiation and Lorentz force 在微生物、热辐射和洛伦兹力作用下，通过弯曲拉伸表面的Eyring-Powell纳米流体的研究

IF 2.1 4区物理与天体物理

Pramana Pub Date : 2025-07-03 DOI: 10.1007/s12043-025-02937-0

Shimaa E Waheed, Galal M Moatimid

{"title":"An investigation of Eyring–Powell nanofluid across a curved stretching surface with micro-organisms, thermal radiation and Lorentz force","authors":"Shimaa E Waheed, Galal M Moatimid","doi":"10.1007/s12043-025-02937-0","DOIUrl":"10.1007/s12043-025-02937-0","url":null,"abstract":"<div><p>The current study explores Eyring–Powell nanofluid (EPF) across a curved stretching surface (CSS) in the presence of micro-organisms, thermal radiation and Lorentz force. It has implications in advanced engineering and biomedical applications. Understanding non-Newtonian fluid behaviour is crucial for optimising heat and mass transfer (HMT), thermal management and targeted drug delivery. We employed Lorentz’s force, chemical reaction and thermal radiation on the fluid flow. As is well known, HMT over the CSS is relevant in biomedical engineering for applications like drug delivery systems and medical implants. The fundamental nonlinear partial differential equations (PDEs) are converted to ordinary differential equations (ODEs) by applying suitable similarity transform and numerically solved by using the Chebyshev spectral method (CSM). Numerical results are concluded by employing tables in attractive representations, which are discussed for different values of non-dimensional curvature radius, permeability coefficient, Eyring–Powell liquid factors, radiation factor, Brownian coefficient, thermophoresis factor, heat generation (absorption) factor, chemical reaction factor, Schmidt factor, Dufour numeral, Soret numeral, magnetic factor, Eckert numeral, bio-convection, Lewis numeral, Peclet numeral and bio-convection factor on the velocity, temperature, concentration and spreading of micro-organisms. The results indicate that the velocity and concentration increase with the rise of curvature radius and permeability coefficient, whereas the distributions of temperature and micro-organisms decrease as these parameters increase. Moreover, all the temperature, concentration and micro-organisms’ distributions increase as the Brownian coefficient increases. Finally, the temperature distribution increases with the assessment of the thermophoresis factor. Conversely, the concentration and propagation of micro-organisms decrease.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 3","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145161706","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

Numerical treatment of heat transfer in a moving porous fin depending on different geometries of the nanofluid 基于纳米流体不同几何形状的移动多孔翅片传热的数值处理

IF 2.1 4区物理与天体物理

Pramana Pub Date : 2025-06-04 DOI: 10.1007/s12043-025-02919-2

Priti Sharma, Surjan Singh, Subrahamanyam Upadhyay

引用次数: 0

Magneto-thermal analysis of the radiative Williamson fluid on a lubricated heated surface with motile micro-organisms and Arrhenius kinetics 具有活动微生物和Arrhenius动力学的润滑受热表面上辐射Williamson流体的磁热分析

IF 2.1 4区物理与天体物理

Pramana Pub Date : 2025-05-28 DOI: 10.1007/s12043-025-02934-3

P K Ratha, S R Mishra, Subhajit Panda

{"title":"Magneto-thermal analysis of the radiative Williamson fluid on a lubricated heated surface with motile micro-organisms and Arrhenius kinetics","authors":"P K Ratha, S R Mishra, Subhajit Panda","doi":"10.1007/s12043-025-02934-3","DOIUrl":"10.1007/s12043-025-02934-3","url":null,"abstract":"<div><p>The rheological behaviour of motile micro-organisms with activation energy within the heat transport phenomena holds significant properties in various areas, including industrial processes, biomedical engineering and environmental science. The present investigation shows the influence of the motile micro-organisms with Arrhenius kinetics on the motion of Williamson fluid over a lubricated surface for the consideration of dissipative heat, thermal radiation and heat generation/absorption. The choice of Williamson fluid is the best approach to accurately depict the non-Newtonian characteristics, which is often used in biological and industrial fields. A suitable similarity approach is useful to transform the governing set of model problems into its non-dimensional form. Further, numerical approaches are utilised to explore the combined influences of the considered factors on the flow phenomena. The validation of the result in special cases is obtained exhibiting a good correlation. However, the important finding are: the velocity bounding surface thickness retards for the interaction of the magnetisation along with the non-Newtonian Weissenberg number and the heat transport phenomena of the fluid enhances significantly with the increasing thermal radiation.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145331","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

Analytical study of Love-type wave propagation in a composite structure of transversely isotropic poroelastic materials 横向各向同性孔隙弹性材料复合结构中love型波传播的解析研究

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-05-26 DOI: 10.1007/s12043-025-02921-8

Komal Gajroiya, Jitander Singh Sikka

{"title":"Analytical study of Love-type wave propagation in a composite structure of transversely isotropic poroelastic materials","authors":"Komal Gajroiya, Jitander Singh Sikka","doi":"10.1007/s12043-025-02921-8","DOIUrl":"10.1007/s12043-025-02921-8","url":null,"abstract":"<div><p>The primary aim of this paper is to undertake an analytical investigation of the dispersion and damping behaviours of Love-type waves propagation in a porous piezoelectric layer sandwiched between a dissipative transversely isotropic poroelastic layer of finite thickness and a homogeneous transversely isotropic poroviscoelastic half-space. The acquisition of a dispersion equation for the propagation of Love-type waves has been accomplished by employing appropriate boundary conditions. Calculations for specific cases have been conducted, demonstrating the transformation of dispersion equation into the conventional Love wave equation in those particular situations. This affirmation validates the current mathematical model. Numerical analyses were performed for the parameters involved and the results were depicted through graphical representations. The effects of viscoelastic parameter, porosity parameters, thickness ratio, dielectric and piezoelectric parameters in the dispersion curves are highlighted. The current investigation could prove valuable in applications related to geophysics, material science, oil and gas exploration and earthquake engineering, aiding in the comprehension of seismic wave propagation characteristics in complex layered structures.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135276","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

Insights into the Vakhnenko–Parkes equation: solitary waves under the influence of power-law nonlinearity 对Vakhnenko-Parkes方程的洞见：幂律非线性影响下的孤波

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-05-26 DOI: 10.1007/s12043-025-02929-0

Turgut Ak, Sharanjeet Dhawan, Mostafa M A Khater, Abdul Hamid Kara

引用次数: 0

Influence of wave-maker shape on the wave attractor 造波器形状对波吸引子的影响

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-05-23 DOI: 10.1007/s12043-025-02927-2

Stepan Elistratov, Daria Ilina

引用次数: 0

Segmented time-varying transformation stochastic resonance and its application in coupling misalignment fault diagnosis 分段时变变换随机共振及其在耦合失调故障诊断中的应用