The European Physical Journal Plus最新文献

Novel Casimir wormholes in Einstein gravity 爱因斯坦引力中的新型卡西米尔虫洞

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-17 DOI: 10.1140/epjp/s13360-024-05801-z

Mohammad Reza Mehdizadeh, Amir Hadi Ziaie

{"title":"Novel Casimir wormholes in Einstein gravity","authors":"Mohammad Reza Mehdizadeh, Amir Hadi Ziaie","doi":"10.1140/epjp/s13360-024-05801-z","DOIUrl":"10.1140/epjp/s13360-024-05801-z","url":null,"abstract":"<div><p>In the context of General Relativity (GR), violation of the null energy condition (NEC) is necessary for existence of static spherically symmetric wormhole solutions. Also, it is a well-known fact that the energy conditions are violated by certain quantum fields, such as the Casimir effect. The magnitude and sign of the Casimir energy depend on Dirichlet or Neumann boundary conditions and geometrical configuration of the objects involved in a Casimir setup. The Casimir energy may act as an ideal candidate for the matter that supports the wormhole geometry. In the present work, we firstly find traversable wormhole solutions supported by a general form for the Casimir energy density assuming a constant redshift function. As well, in this framework, assuming that the radial pressure and energy density obey a linear equation of state, we derive for the first time Casimir traversable wormhole solutions admitting suitable shape function. Then, we consider three geometric configurations of the Casimir effect such as (i) two parallel plates, (ii) two parallel cylindrical shells, and (iii) two spheres. We study wormhole solutions for each case and their property in detail. We also check the weak and strong energy conditions in the spacetime for the obtained wormhole solutions. The stability of the Casimir traversable wormhole solutions are investigated using the Tolman-Oppenheimer-Volkoff (TOV) equation. Finally, we study trajectory of null as well as timelike particles along with quasi-normal modes (QNMs) of a scalar field in the wormhole spacetime.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Higher order approximations in quantum speed limit time of a qubit coupled to XXZ spin chain environment 与 XXZ 自旋链环境耦合的量子比特的量子速度极限时间的高阶近似值

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-16 DOI: 10.1140/epjp/s13360-024-05815-7

Muhammad Musadiq, Mehvish Shahzadi, Salman Khan

{"title":"Higher order approximations in quantum speed limit time of a qubit coupled to XXZ spin chain environment","authors":"Muhammad Musadiq, Mehvish Shahzadi, Salman Khan","doi":"10.1140/epjp/s13360-024-05815-7","DOIUrl":"10.1140/epjp/s13360-024-05815-7","url":null,"abstract":"<div><p>The quantum speed limit (QSL) time of a single qubit coupled to Heisenberg <i>XXZ</i> spin bath is investigated. The time convolutionless (TCL) projection operators technique is followed for investigating the second (TCL2), third (TCL3) and fourth (TCL4) order approximations in QSL time of centrally interacting qubit. The results are discussed up to fourth order of perturbation expansions of the non-Markovian master equation of motion. Behavior of QSL time is studied against temperature, interaction time and coupling strength for second, third and fourth orders of master equation using TCL technique. The behavior of QSL time becomes less perturbative for third and fourth order approximations as compared to second order. It is investigated that QSL time of qubit becomes constant very quickly in the low temperature limit for third and fourth order approximation, which means evolution speed of qubit is less affected for higher orders of approximations. QSL time for third and fourth orders of TCL gives much better results at high temperature and also behave well at short times. It is observed that, as the order of the TCL master equation increases, the accuracy of the approximation improves, but the complexity of the equation also increases due to involvement of more and more interaction terms in the TCL master equation.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Anisotropic stellar modeling via MIT Bag model EoS admitting Finch–Skea spacetime in f(Q) gravity 通过 MIT Bag 模型 EoS 在 f(Q) 引力下接纳芬奇-斯基亚时空的各向异性恒星建模

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-16 DOI: 10.1140/epjp/s13360-024-05778-9

Allah Ditta, Munaza Asia, Abdelghani Errehymy, G. Mustafa, S. K. Maurya, Asif Mahmood

{"title":"Anisotropic stellar modeling via MIT Bag model EoS admitting Finch–Skea spacetime in f(Q) gravity","authors":"Allah Ditta, Munaza Asia, Abdelghani Errehymy, G. Mustafa, S. K. Maurya, Asif Mahmood","doi":"10.1140/epjp/s13360-024-05778-9","DOIUrl":"10.1140/epjp/s13360-024-05778-9","url":null,"abstract":"<div><p>This study evaluates the viability and stability of anisotropic compact stellar objects by utilizing the Finch–Skea spacetime solutions in <i>f</i>(<i>Q</i>) gravity, where <i>Q</i> is a nonmetricity scalar that incorporates gravitational effects. The physical properties of the compact star EXO 1785-248 are investigated by employing a static spherical metric in the inner region and Schwarzschild spacetime in the outer region. The unknown parameters are determined using observed values of the radius and mass of the studied compact star. The suggested mass and radius values of EXO 1785-248 from existing literature are utilized. Subsequently, calculations are conducted to determine the essential features of the compact star and establish its stability and physical existence. Various aspects are analyzed, including energy density, pressure profiles, gradients, anisotropic factors, energy conditions, sound speeds, Tolman–Oppenheimer–Volkoff forces, equation of state components, mass function, compactification, and redshift, in order to achieve this objective.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Lag matrix projection synchronization for discrete chaotic systems and its application to image encryption 离散混沌系统的滞后矩阵投影同步及其在图像加密中的应用

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-15 DOI: 10.1140/epjp/s13360-024-05789-6

Wenchu Wu, Mingyu Lu, Xin Guan, Ziheng Yang

{"title":"Lag matrix projection synchronization for discrete chaotic systems and its application to image encryption","authors":"Wenchu Wu, Mingyu Lu, Xin Guan, Ziheng Yang","doi":"10.1140/epjp/s13360-024-05789-6","DOIUrl":"10.1140/epjp/s13360-024-05789-6","url":null,"abstract":"<div><p>Chaotic systems are widely used in the field of secure communications due to their initial value sensitivity, long-term unpredictability and other characteristics. In this paper, a Lag Matrix Projection Synchronization (LMPS) scheme based on discrete chaotic system is proposed, which can adapt to a variety of synchronization including lag synchronization, simultaneous synchronization, projection synchronization, inverse synchronization, and complete synchronization. In order to verify the feasibility of the scheme, we also design a new four-dimensional discrete chaotic system, which is fully analyzed by numerical simulation. Simulation results show that the LMPS synchronization scheme can achieve synchronization with an average of only 8 iterations, and the synchronization error is controlled within the range of 10<sup>–10</sup>, which reflects the high efficiency and accuracy of the scheme. In addition, we apply it to the field of image encryption, and the security analysis shows that the system performs well in terms of encryption effect, key space size, and resistance to noise attack, and can effectively guarantee the confidentiality and integrity of data.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Effect of Hall current generated by a radial magnetic field on transient natural convection between vertical annuli 径向磁场产生的霍尔电流对垂直环面间瞬态自然对流的影响

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-15 DOI: 10.1140/epjp/s13360-024-05786-9

Vijay Kumar Sukariya, Anurag, Atul Jakhar, Anand Kumar

{"title":"Effect of Hall current generated by a radial magnetic field on transient natural convection between vertical annuli","authors":"Vijay Kumar Sukariya,  Anurag, Atul Jakhar, Anand Kumar","doi":"10.1140/epjp/s13360-024-05786-9","DOIUrl":"10.1140/epjp/s13360-024-05786-9","url":null,"abstract":"<div><p>The Hall effect phenomena has a long standing history, yet its relevance and application continue to grow across numerous industries. Spanning from technological advancements to innovations in medical equipment, the influence of Hall current effects remains critical for enhancing efficiency and driving innovation. Despite its origins over a century ago, the phenomena remains highly relevant and is constantly being integrated into modern systems, reflecting its enduring significance and versatility across both scientific and industrial domains. Building on these historical context, the present study examines the effects of Hall current on transient natural convective flow within cylindrical annuli subjected to a radial magnetic field. The system of partial differential equations derived from the mathematical model is first transformed into a nondimensional form by applying the relevant nondimensional parameters. Subsequently, these nondimensional PDEs are addressed using the implicit Crank–Nicolson finite difference method. Furthermore, the results section offers detailed graphical representations of both primary and secondary velocity profiles, as well as quantities data on temperature and velocities, along with the Nusselt number and skin friction at the cylinder boundaries. These results are systematically presented across a range of flow parameters, providing in-depth analysis of the system’s response to varying conditions. The key outcomes of this study indicate that both the Hall parameter and the radii ratio play a significant role in augmenting the primary and secondary velocities, as well as increasing skin friction values. On the other hand, the Prandtl number and Hartmann number exhibit opposing influences on the primary velocity, each influencing it in a contrasting manner.\u0000</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Effect of strong magnetic field on thermodynamic properties of quarkonia: NUFA method 强磁场对夸克热力学性质的影响：NUFA 方法

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-15 DOI: 10.1140/epjp/s13360-024-05784-x

Rishabh Sharma, Shashanka Shekhar Dash, Vineet Kumar Agotiya

引用次数: 0

Localization of matters coupled non-minimally to gravity on scalar thick branes 标量厚支链上与引力非最小耦合的物质的局域化

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-14 DOI: 10.1140/epjp/s13360-024-05725-8

Muhammad Taufiqur Rohman, Triyanta, Agus Suroso

引用次数: 0

Comparative study between Nirmala and Sombor indices based on their applicability, degeneracy and smoothness 基于适用性、退化性和平稳性的尼尔马拉指数和松博指数比较研究

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-14 DOI: 10.1140/epjp/s13360-024-05768-x

Virendra Kumar, Shibsankar Das

{"title":"Comparative study between Nirmala and Sombor indices based on their applicability, degeneracy and smoothness","authors":"Virendra Kumar, Shibsankar Das","doi":"10.1140/epjp/s13360-024-05768-x","DOIUrl":"10.1140/epjp/s13360-024-05768-x","url":null,"abstract":"<div><p>A topological index (or descriptor) is a numerical demonstration of a molecular graph associated with a chemical compound that directly correlates with its physical and chemical characteristics through quantitative structure–property relationship (QSPR) analysis. This article is concerned with the mathematical bounds and expressions of the Nirmala index for chemical graphs and its comparison with the Sombor index through QSPR analysis. More precisely, a comparative study between the Nirmala index and the Sombor index is presented using the linear, quadratic and multi-linear regression analysis over the physico-chemical properties of octane isomers to test the predictive potential of the index. Further, the degeneracy and smoothness (structure sensitivity and abruptness) are calibrated of the Nirmala and Sombor indices using the chemical isomers data sets such as octane, nonane and decane. Finally, the lower and upper bounds of the Nirmala index are investigated using the sets of chemical graphs and trees. Additionally, the expressions of the Nirmala index and its extremal values are also examined for different types of hexagonal systems. The obtained correlation values and <i>p</i>-values of both indices through multi-linear regression analysis are more significant, indicating the reliability and applicability of the findings. Therefore, these indices may be utilized to predict the properties of various chemical compounds and drugs in the QSPR studies.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

On the compressible quasilinear viscoelastic simple uniaxial deformation 关于可压缩准线性粘弹性简单单轴变形

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-14 DOI: 10.1140/epjp/s13360-024-05724-9

Anna Maria Cherubini, Riccardo De Pascalis

引用次数: 0

Tunable cratering of lateral Goos–Hänchen shifts in reflection and transmission of structured light in chiral atomic medium 手性原子介质中结构光的反射和透射中可调控的 Goos-Hänchen 横向偏移的火山口效应

IF 2.8 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2024-11-14 DOI: 10.1140/epjp/s13360-024-05792-x

Rahat Ullah, Shehzad Khan, Amina, Javaid Khan

{"title":"Tunable cratering of lateral Goos–Hänchen shifts in reflection and transmission of structured light in chiral atomic medium","authors":"Rahat Ullah, Shehzad Khan,  Amina, Javaid Khan","doi":"10.1140/epjp/s13360-024-05792-x","DOIUrl":"10.1140/epjp/s13360-024-05792-x","url":null,"abstract":"<div><p>The birefringence cratering of reflection, transmission and corresponding Goos Hänchen (GH) shift are investigated in reflection and transmission beams through four level chiral atomic medium of structured light. The reflection and transmission of left and right circularly polarized light obey normalization condition and strong cratering oscillation functions of positions and azimuthal quantum number <span>(ell )</span> of control field. Crater types reflection and transmission are investigated whose numbers increase with azimuthal quantum numbers having varying in shapes. The GH shifts in reflection and transmission is positive and oscillated with position <span>(x/lambda )</span> and <span>(y/lambda )</span>. The numbers of crater in GH shifts depend on the azimuthal quantum number <span>(ell )</span> of control field. The values of both GH shift in reflection and transmission varies in the range of <span>(6lambda le S_R^{(-)}le 12lambda )</span> and <span>(6lambda le S_T^{(-)}le 12lambda )</span> with increasing craters to increase azimuthal quantum number <span>(ell )</span> of control field. The modified results of the GH shifts are useful for biosensor and plasmonster technology.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 11","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142636719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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