Pramana最新文献_第3页

Graphene is neither relativistic nor non-relativistic: thermodynamics aspects

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-30 DOI: 10.1007/s12043-024-02888-y

Thandar Zaw Win, Cho Win Aung, Gaurav Khandal, Sabyasachi Ghosh

{"title":"Graphene is neither relativistic nor non-relativistic: thermodynamics aspects","authors":"Thandar Zaw Win, Cho Win Aung, Gaurav Khandal, Sabyasachi Ghosh","doi":"10.1007/s12043-024-02888-y","DOIUrl":"10.1007/s12043-024-02888-y","url":null,"abstract":"<div><p>Discovery of electron hydrodynamics in graphene systems has opened a new scope of theoretical research in condensed matter physics, which was traditionally well cultivated in science and engineering as a non-relativistic hydrodynamics and in high energy nuclear and astrophysics as relativistic hydrodynamics. Electrons in graphene follow neither non-relativistic nor relativistic hydrodynamics. Similar to other hydrodynamical descriptions, the energy–momentum tensor of graphene also has an ideal component and a dissipating component, but in an unconventional way, so popularly, it is sometimes called as unconventional hydrodynamics. The unconventional part of the dissipating component for the energy–momentum tensor is recently addressed in <i>Phys. Rev. B</i> <b>108</b>, 235172 (2023) but its ideal component, which is connected with the thermodynamics of graphene, has not been zoomed in a very systematic way. This article has gone through systematic microscopic calculations of thermodynamical quantities like pressure, energy density, etc., of electron-fluid in graphene and compared with the corresponding estimations for non-relativistic and ultra-relativistic cases. We have sketched the temperature and Fermi energy dependency of electron thermodynamics for graphene and other cases where the transition from Fermi liquid to Dirac fluid domain is explored. An equivalent transition for quark matter is also discussed. Interestingly, an enhancement of specific heat within the low-temperature and Fermi energy region is found, which may be connected to the recently observed Wiedemann–Franz law violation.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110003","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

Phase-space distributions in information theory

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-30 DOI: 10.1007/s12043-024-02875-3

Vikash Kumar Ojha, Ramkumar Radhakrishnan, Siddharth Kumar Tiwari, Mariyah Ughradar

引用次数: 0

On the influence of natural frequency on the double Hopf bifurcation system forced by excitations with a low frequency

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-28 DOI: 10.1007/s12043-024-02882-4

Miaorong Zhang, Yin Zhou, Qinsheng Bi, Hongliu Guo

{"title":"On the influence of natural frequency on the double Hopf bifurcation system forced by excitations with a low frequency","authors":"Miaorong Zhang, Yin Zhou, Qinsheng Bi, Hongliu Guo","doi":"10.1007/s12043-024-02882-4","DOIUrl":"10.1007/s12043-024-02882-4","url":null,"abstract":"<div><p>This paper mainly focusses on the influence of natural frequency on a double Hopf bifurcation system with two-time scale. While the attractors may vary as the excitation amplitude expands, we try to discover all the characteristic of influence by gradually increasing the excitation amplitude. Based on the grasped mechanism of oscillators as well as comparative research concentrating at different values of natural frequency, some regular conclusions can be reached. When the excitation amplitude is small, only oscillators of single mode exist, while the natural frequency responsible for the sub-plane with no oscillation makes no difference to the one with oscillations. With the amplitude increasing, the system may switch between oscillations of different modes. The natural frequency may affect the frequency of bursting oscillation in its own sub-plane and the time that the system switches from single-mode oscillation to mixed-mode oscillations. For relatively large amplitudes, oscillations with mixed modes occupy the whole movements. The natural frequency corresponding to one sub-plane may affect the amplitude of bursting oscillation or the time that the system alternates between the spiking state and the quiescent state as well as the routes that the trajectory goes through in the other sub-plane.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109837","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

Perturbations of optical solitons in magneto-optic waveguides incorporating multiplicative white noise and sixth-order dispersion: a study of the Sasa–Satsuma equation

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-25 DOI: 10.1007/s12043-024-02848-6

Elsayed M E Zayed, Khaled A E Alurrfi, Abeer M M Hasek, Ahmed H Arnous, Aydin Secer, Muslum Ozisik, Mustafa Bayram, Sachin Kumar

{"title":"Perturbations of optical solitons in magneto-optic waveguides incorporating multiplicative white noise and sixth-order dispersion: a study of the Sasa–Satsuma equation","authors":"Elsayed M E Zayed, Khaled A E Alurrfi, Abeer M M Hasek, Ahmed H Arnous, Aydin Secer, Muslum Ozisik, Mustafa Bayram, Sachin Kumar","doi":"10.1007/s12043-024-02848-6","DOIUrl":"10.1007/s12043-024-02848-6","url":null,"abstract":"<div><p>Our study examines the impact of sixth-order dispersion and multiplicative white noise on the transmission of optical solitons within magneto-optic waveguides. Our findings offer valuable insights that are crucial for the advancement of optical communications. We demonstrate how these factors affect soliton behaviour by developing and analysing a stochastic version of the Sasa–Satsuma equation, which describes the dynamics of optical solitons in dispersive media. Our research introduces an enhanced analytical approach that addresses the complexities introduced by these perturbations, specifically by modifying the sub-ordinary differential equation (sub-ODE) method. The investigation reveals the substantial influence of sixth-order dispersion and multiplicative white noise on the quality and stability of soliton transmission in such waveguides. These findings emphasise the significant importance of considering these factors in designing and optimising optical communication systems, particularly those utilising the propagation of optical solitons. This research represents a substantial advancement in our understanding of and ability to mitigate the effects of higher-order dispersion and stochastic perturbations on soliton-based communication technology.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109744","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

Heat transfer analysis of a fully wetted inclined moving fin with temperature-dependent internal heat generation using DTM-Pade approximant and machine learning algorithms

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-25 DOI: 10.1007/s12043-024-02880-6

J Komathi, N Magesh, K Venkadeshwaran, K Chandan, R S Varun Kumar, Amal Abdulrahman

{"title":"Heat transfer analysis of a fully wetted inclined moving fin with temperature-dependent internal heat generation using DTM-Pade approximant and machine learning algorithms","authors":"J Komathi, N Magesh, K Venkadeshwaran, K Chandan, R S Varun Kumar, Amal Abdulrahman","doi":"10.1007/s12043-024-02880-6","DOIUrl":"10.1007/s12043-024-02880-6","url":null,"abstract":"<div><p>This study investigates the thermal properties of a longitudinally inclined moving porous fin with varying internal heat generation. The approach takes into account the combined influence of natural convection, radiation, and the wet condition while modelling the fin’s energy equation. Using dimensionless terms, the governing energy balance equation is converted into an ordinary differential equation (ODE), which is then solved using the Differential transform method (DTM) and Pade approximant. The machine learning (ML) algorithms is also implemented for detecting temperature fluctuations in wetted fins. The ability of stacking ensemble ML model is employed to strengthen the reliability and accuracy of forecasts, which demonstratrates the improved regression predictions with absolute error rates ranging at 10<sup>−6</sup>. The coefficient of regression of 1 indicates the best fit for the data signifying efficient ML prediction. The graphical representations demonstrate how thermal factors influence temperature dispersion. The analysis reveals that the fin’s temperature rises with increasing ambient temperature, nondimensional internal heat generation, generation number, power exponent, and Peclet number. However, under these conditions the temperature gradient reduces. Furthermore, greater values of the convective, radiative, wet porous, and inclination angle parameters result in lower fin temperatures, which aids in cooling while increasing the temperature gradient.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109754","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

Self-heating optimisation of nanosheet field effect transistor performance with physics-based calibrated simulation setup

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-25 DOI: 10.1007/s12043-024-02883-3

S Bhuvaneshwari, Archana Pandey

{"title":"Self-heating optimisation of nanosheet field effect transistor performance with physics-based calibrated simulation setup","authors":"S Bhuvaneshwari, Archana Pandey","doi":"10.1007/s12043-024-02883-3","DOIUrl":"10.1007/s12043-024-02883-3","url":null,"abstract":"<div><p>One of the best ways to scale down below sub-7 nm technology nodes seems to be to use vertically stacked horizontal nanosheet gates all around the transistors. To analyse transistor structure and improve the performance of the device, in this work, we compare the physical models, geometrical configuration and electrical performance of the vertically stacked horizontal nanosheet transistors. We investigate how the gate-length, gate oxide thickness, work function engineering, nanosheets – their width, height, number of stacked sheets with doping concentration, gate materials can affect the electrical performance and here we present the suitable design required for vertically stacked nanosheet field effect transistors (FETs) for improved performance using TCAD calibration. Also, the self-heating effect is analysed by varying the number of nanosheets, width of nanosheets using a thermodynamic model. The calibration set-up exhibits good efficiency towards the technology node. The significant device variability might result from the stacked nanosheet architectures becoming more complicated over the adverse device improvement.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109667","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

Exploring slip-enhanced MHD Williamson nanofluid dynamics: interplay of a permeable stretching sheet with thermal radiation and chemical reaction 探索滑移增强MHD Williamson纳米流体动力学：可渗透拉伸片与热辐射和化学反应的相互作用

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-21 DOI: 10.1007/s12043-024-02867-3

Sadia Irshad, Shah Jahan, Muhammad Sohail, Muhammad Hussain Ali

{"title":"Exploring slip-enhanced MHD Williamson nanofluid dynamics: interplay of a permeable stretching sheet with thermal radiation and chemical reaction","authors":"Sadia Irshad, Shah Jahan, Muhammad Sohail, Muhammad Hussain Ali","doi":"10.1007/s12043-024-02867-3","DOIUrl":"10.1007/s12043-024-02867-3","url":null,"abstract":"<div><p>The study focusses on analysing the intricate dynamics of heat and mass transfer in non-Newtonian fluids, emphasising the efficacy of the Williamson fluid model in characterising situations with diverse viscosities. This study investigates the mass and heat transfer of a magnetohydrodynamic Williamson fluid across a surface with stretched pores, taking into account the radiation from heat sources and chemical reactions. We reduce the extremely nonlinear governing equations to more manageable forms by applying similarity invariants and obtain the numerical solution by combining the shooting method and the BVP4C method to solve the reduced systems of ordinary differential equations MATLAB visualisations demonstrate that the non-dimensional parameters are closely related to the body of current literature. Notably, the data indicate an intensification of the temperature profile at higher radiation, Williamson and magnetic factor values, while fluid motion experiences a decrease at these elevated levels. This study’s results hold significant implications for industries such as food processing, glassmaking, oil extraction and others related to fluids, as it links higher Williamson and magnetic parameters to reduced fluid mobility, while higher Williamson, magnetic and radiation factors enhance the temperature profile. Overall, this work provides insightful information about how non-Newtonian fluids behave under various physical conditions, with useful applications for a broad range of industrial processes. The purpose of this study is to look at the dynamics of Williamson nanofluids under slip-enhanced magnetohydrodynamics, having a particular emphasis on the interaction of thermal radiation, chemical reaction and a permeable stretching sheet. This research uses the shooting technique and the BVP4C approach to examine the complicated behaviour of the system in depth.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"99 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995708","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

Role of magnetic anisotropy constant orders and thermal noise on skyrmion formation in the Co(/)Pt square nanostructure 磁各向异性常数阶和热噪声对Co (/) Pt方形纳米结构中skyrmion形成的影响

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-21 DOI: 10.1007/s12043-024-02878-0

Tamali Mukherjee, V Satya Narayana Murthy

引用次数: 0

Solitary wave solutions to a (3 + 1)-dimensional extended Zakharov–Kuznetsov model in a dusty magnetised plasma 尘埃磁化等离子体中（3 + 1）维扩展Zakharov-Kuznetsov模型的孤波解

IF 1.9 4区物理与天体物理

Pramana Pub Date : 2025-01-21 DOI: 10.1007/s12043-024-02876-2

Amit Prakash, Swati

引用次数: 0

Study of ground-state bands in Er and Yb nuclei with (Nge 100) 铒和镱原子核基态带的研究 (Nge 100)