Chinese Journal of Physics最新文献

Chaos in a triple diffusive system involving a viscoelastic fluid layer 涉及粘弹性流体层的三重扩散系统中的混沌

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-06-01 Epub Date: 2026-01-29 DOI: 10.1016/j.cjph.2026.01.024

N.D. Pavan , S. Pranesh , P.G. Siddheshwar

This study investigates the linear and weakly nonlinear stability analysis in a Rayleigh-Bénard configuration with a viscoelastic fluid layer influenced by two additional solutal components. The governing equations for both stationary and oscillatory convective regimes, and the critical point at which convection sets in is derived. The comparative analysis is performed for three different viscoelastic fluid models: Oldroyd-B, Maxwell, Rivlin-Ericksen fluid, along with the Newtonian fluid model. In weakly nonlinear stability analysis, a generalized eight-mode Lorenz model is developed that satisfies the general properties of a classical Lorenz model. From this reduced model, the critical points and Hopf-Rayleigh number, representing the initiation of chaos through Hopf bifurcation are determined. The Lyapunov exponents are used to characterize the chaotic, periodic and quasi-periodic motions of the system. The results show that the viscoelastic and triple diffusion parameters affect the initiation of convection and transition to chaos. It is also observed that the Maxwell fluid exhibits the earliest initiation of chaos and the Newtonian fluid the latest, with Oldroyd-B and Rivlin-Ericksen exhibiting intermediate behaviour. The presence of additional solutal concentrations delays the onset of chaotic motion.

本文研究了受两种附加溶质组分影响的粘弹性流体层的瑞利-巴姆纳德构型的线性和弱非线性稳定性分析。导出了稳定对流和振荡对流的控制方程，以及对流的临界点。对比分析了三种不同的粘弹性流体模型：Oldroyd-B、Maxwell、Rivlin-Ericksen流体和牛顿流体模型。在弱非线性稳定性分析中，建立了一个满足经典洛伦兹模型一般性质的广义八模洛伦兹模型。从该简化模型出发，确定了通过Hopf分岔引发混沌的临界点和Hopf- rayleigh数。李雅普诺夫指数用于描述系统的混沌、周期和准周期运动。结果表明，粘弹性和三重扩散参数影响对流的产生和向混沌的转变。麦克斯韦流体表现出最早的混沌起始，牛顿流体表现出最晚的混沌起始，Oldroyd-B和Rivlin-Ericksen流体表现出中间行为。附加溶质浓度的存在延迟了混沌运动的开始。

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引用次数: 0

Thermodynamic performance of a quantum Stirling heat engine in Lipkin-Meshkov-Glick model with magnetic field 具有磁场的Lipkin-Meshkov-Glick模型中量子斯特林热机的热力学性能

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-06-01 Epub Date: 2025-12-04 DOI: 10.1016/j.cjph.2025.12.005

Feilang Ning , Chengjian Yang , Liu Long

This paper explores the quantum Stirling cycle with a working medium modeled by the two-sided Lipkin-Meshkov-Glick (LMG) model under the influence of an external magnetic field and a symmetric cross-interaction. Shannon entropy is then used to derive the necessary quantities for analyzing the quantum Stirling heat engine, and its four-stage cycle is examined using the introduced quantum working medium. Subsequently, the efficiency and thermodynamic performance are calculated based on the established relations. Three scenarios are considered: the anisotropic XY model, the Ising model, and the mixed ferromagnetic model. The findings demonstrate that the Stirling cycle can function as a refrigerator, accelerator, heat engine, or heater, with its operational mode highly tunable via external parameters, including the magnetic field, the anisotropy parameter, the temperature ratio of the heat baths, and the ratio of the magnetic coupling strengths. Transitions between these regimes are governed by quantum fluctuations, anisotropy effects, and thermal gradients. The efficiency and thermodynamic performance of the cycle are analyzed under variation of these parameters. These insights provide a foundation for optimizing quantum thermal devices for energy conversion and refrigeration applications.

本文研究了在外加磁场和对称相互作用的影响下，用双边Lipkin-Meshkov-Glick （LMG）模型模拟的工作介质的量子斯特林循环。然后利用香农熵导出了量子斯特林热机分析的必要量，并利用引入的量子工质对其四阶段循环进行了检验。然后，根据建立的关系计算了效率和热力学性能。考虑了三种情况：各向异性XY模型、Ising模型和混合铁磁模型。研究结果表明，斯特林循环可以作为冰箱、加速器、热机或加热器，其工作模式可通过外部参数（包括磁场、各向异性参数、热浴温度比和磁耦合强度比）进行高度可调。这些制度之间的转变是由量子涨落、各向异性效应和热梯度控制的。分析了这些参数变化下循环的效率和热力学性能。这些见解为优化用于能量转换和制冷应用的量子热器件提供了基础。

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引用次数: 0

Optical aspect of cosmological black holes in Einstein-Maxwell-dilaton theory 爱因斯坦-麦克斯韦膨胀理论中宇宙学黑洞的光学方面

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-06-01 Epub Date: 2025-11-03 DOI: 10.1016/j.cjph.2025.10.032

Hajar Belmahi , Amin Mohamed Rbah

Motivated by string theory scenarios, we study the optical aspect of AdS black holes in Einstein-Maxwell-dilaton theory. Concretely, we investigate and examine the shadows and the deflection angle of light rays by such cosmological black holes. Regarding the shadows, we first deal with the non-rotating solutions. As expected, we obtain perfect circular shadows where their sizes are controlled by the involved parameters including the charge and the cosmological constant. Combining the Newman-Janis formalism and the Hamilton-Jacobi algorithm, we approach the rotating black hole shadows using one dimensional real curves. Among others, we observe that the size and the shape of the shadows depend on certain parameters such as the rotation parameter. To make contact with the Event Horizon Telescope observational data, we show that certain constraints should be imposed on such parameters. Then, we study the behaviors of the light rays near such cosmological black holes by computing the deflection angle in terms of the Einstein-Maxwell-dilaton theory parameters. Specifically, we reveal that the effect of the cosmological constant on the deflection angle depends on the coupling between the black hole parameters. Introducing the rotation parameter, we observe that this effect becomes similar to that of the cosmological constant in ordinary AdS black holes.

受弦理论场景的启发，我们在爱因斯坦-麦克斯韦-膨胀理论中研究了AdS黑洞的光学方面。具体来说，我们研究和检验了这些宇宙黑洞的阴影和光线的偏转角度。关于阴影，我们首先处理非旋转解。正如预期的那样，我们得到了完美的圆形阴影，其大小由包括电荷和宇宙学常数在内的相关参数控制。结合Newman-Janis形式和Hamilton-Jacobi算法，利用一维实曲线逼近旋转黑洞阴影。其中，我们观察到阴影的大小和形状取决于某些参数，如旋转参数。为了与事件视界望远镜的观测数据进行接触，我们表明应该对这些参数施加某些限制。然后，我们根据爱因斯坦-麦克斯韦-膨胀理论参数计算光线在这类宇宙黑洞附近的偏转角，研究了光线在这类宇宙黑洞附近的行为。具体来说，我们揭示了宇宙学常数对偏转角的影响取决于黑洞参数之间的耦合。引入旋转参数后，我们观察到这种效应与普通AdS黑洞的宇宙学常数相似。

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引用次数: 0

Extremal decomposable entanglement witnesses from limited local measurements in two-qudit systems 二量程系统中有限局部测量的极值可分解纠缠见证

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-06-01 Epub Date: 2025-12-29 DOI: 10.1016/j.cjph.2025.12.032

Yi-Fan Gao , Shu-Qian Shen , Ming Li , Lei Li , Shao-Ming Fei

An entanglement witness, used as a tool for detecting entanglement, is widely applied in experiments. Compared with methods that rely on the quantum-state tomography, entanglement witnesses based on local measurements require only partial statistical information, avoiding the need for complete state reconstruction. Extremal decomposable entanglement witnesses from limited fixed sets of local measurements were constructed in [Phys. Rev. A 101, 062,319 (2020)]. However, the characterization of extremal decomposable entanglement witnesses in general two-qudit systems is not thoroughly studied. In this paper, we present a complete characterization of extremal decomposable entanglement witnesses derived from this limited fixed set of local measurements in two-qudit systems.

纠缠见证作为一种检测纠缠的工具，在实验中得到了广泛的应用。与依赖于量子态层析成像的方法相比，基于局部测量的纠缠见证只需要部分统计信息，避免了完全状态重建的需要。从有限固定的局部测量集构造了极限可分解纠缠见证。[j].农业工程学报，1999,17(5):444 - 444。然而，对于一般双量程体系中极值可分解纠缠见证的性质研究并不深入。在本文中，我们给出了在二量子位系统中由这一有限固定的局部测量集导出的极端可分解纠缠见证的完整表征。

引用次数: 0

A New Reduction Method to Find Rogue Waves of the Nonlinear Schro....dinger Equation 一种寻找非线性Schro异常波的新约简方法....谔方程

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-06-01 Epub Date: 2026-01-30 DOI: 10.1016/j.cjph.2026.01.022

Dazhao Lü , Yanying Cui , Xiufang Wang

Rogue waves of the focusing nonlinear Schrödinger equation are obtained by a novel and highly efficient composite function reduction method. Compared to existing literatures, instead of the nonlinear differential operators

{[f (p_{i}) \partial_{p_{i}}]}^{k}

and

{[f (q_{j}) \partial_{q_{j}}]}^{l}

, the only linear differential operators

\partial_{λ}^{k}

and

\partial_{μ}^{l}

are used in this paper, which significantly simplify the computational process for deriving rogue waves and the analytical expressions of rogue waves. On the technical aspect, this research makes two key contributions to soliton theory. First, it broadens the applicability of the Grammian technique to a wider range by generalizing the constants p_i and q_j in the nonlinear dispersion relation to the functions

p_{i} = h (λ), q_{j} = h (μ)

. Second, it adds diversity to the available reduction techniques in soliton theory by introducing the composite function reduction method.

采用一种新颖高效的复合函数约简方法得到了聚焦非线性Schrödinger方程的异常波。与已有的文献相比，本文使用的是线性微分算子∂λk和∂μl，而不是非线性微分算子[f(pi)∂pi]k和[f(qj)∂qj]l，极大地简化了异常波推导和异常波解析表达式的计算过程。在技术方面，本研究对孤子理论做出了两个关键贡献。首先，通过将非线性色散关系中的常数pi和qj推广到函数pi=h(λ),qj=h(μ)，拓宽了Grammian技术的适用范围。其次，引入复合函数约简方法，增加了孤子理论中现有约简方法的多样性。

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引用次数: 0

Thermal radiation and salt finger-induced chaotic double-diffusive convection with concentration modulation along an inclined plane 热辐射与盐指沿斜面浓度调制的混沌双扩散对流

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-06-01 Epub Date: 2026-01-31 DOI: 10.1016/j.cjph.2026.01.026

Rohit Kannaujiya , B.S. Bhadauria

The study examines the impact of time-dependent solute on an inclined plane under thermal radiation using an analytical approach. The ordinary differential equation, which is time dependent and non-autonomous, is used to frame the problem. The nonlinear theory and solvability condition are used to create the Ginzburg Landau equation. A nonlinear stability analysis of the stationary mode convection has been carried out and heat and mass transfer in terms of Sherwood number (Sh) and Nusselt number (Nu) are obtained. The Sherwood number (Sh) and Nusselt number (Nu) are found in terms of Rayleigh number, Lewis number, amplitude of convection, and analyzed graphically for various parameters of the system. The Lorenz model is employed to analyze chaotic convection near onset, showing transitions from steady to chaotic states. Flow patterns are visualized using streamlines, isotherms, and isohalines. In case of In-Phase Modulation, ω & δ have negligible effects while heat and mass transport increased in Out-phase and Upper Boundary Phase Modulation. Lewis number (Le) decreases the heat transfer while increasing the mass transfer due to the time-dependent concentration and surfaces concentrated from the above i.e. finger salt process. It is concluded that convection is less pronounced on the inclined surface compared to horizontal surface, which shows that Nu increases more quickly for horizontal fluid layer that it does for inclined fluid layer.

该研究考察了时间依赖的溶质对斜面的影响，在热辐射下使用分析方法。用非自治的常微分方程来描述问题。利用非线性理论和可解性条件建立了金兹堡-朗道方程。对定模对流进行了非线性稳定性分析，得到了用Sherwood数（Sh）和Nusselt数（Nu）表示的传热传质。通过Rayleigh数、Lewis数、对流振幅，求出了Sherwood数（Sh）和Nusselt数（Nu），并对系统各参数进行了图形化分析。采用Lorenz模型分析混沌对流的近起始状态，显示了从稳态到混沌状态的转变。流动模式使用流线、等温线和等盐线可视化。在同相调制情况下，ω &； δ的影响可以忽略不计，而在同相调制和上边界调制情况下，热量和质量输运增加。刘易斯数（Le）减少了传热，同时增加了传质，这是由于时间依赖的浓度和从上述过程中浓缩的表面，即手指盐过程。结果表明，相对于水平流体层，倾斜流体层对流较弱，表明水平流体层Nu的增大速度要快于倾斜流体层。

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引用次数: 0

Electrically controlled laser generation in a photonic crystal - liquid crystal - metal microcavity 光子晶体-液晶-金属微腔的电控激光产生

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-04-01 Epub Date: 2026-01-07 DOI: 10.1016/j.cjph.2026.01.004

Daniil S. Buzin , Pavel S. Pankin , Dmitrii N. Maksimov , Vitaly S. Sutormin , Gavriil A. Romanenko , Rashid G. Bikbaev , Sergey V. Nedelin , Nikita A. Zolotovskii , Igor A. Tambasov , Stepan Ya. Vetrov , Kuo-Ping Chen , Ivan V. Timofeev

A comprehensive approach for simulating lasing dynamics in a liquid crystal based laser is presented. The approach takes into account the transformation of the liquid crystal structure caused by applied voltage. In particular, it allows us to explicitly account for a resonant mode frequency shift in the laser equations. The laser dynamic is described by a set of coupled non-linear differential equations for dye polarizations, population densities and the electromagnetic fields. The proposed model is applied to a photonic crystal - metal microcavity filled with a resonant nematic liquid crystal layer doped with a dye. The calculated lasing spectra governed by external electric field are verified in comparison with measured spectra.

提出了一种模拟液晶激光器激光动力学的综合方法。该方法考虑了外加电压对液晶结构的影响。特别是，它允许我们明确地解释激光方程中的谐振模式频移。激光动力学用一组耦合的非线性微分方程来描述染料偏振、密度和电磁场。将该模型应用于掺杂染料的向列相液晶层谐振型光子晶体-金属微腔。计算得到的外电场作用下的激光光谱与实测光谱进行了对比验证。

引用次数: 0

Tunable spin-wave resonance and chirality control in concentric nanotori for advanced spintronic applications 可调谐自旋波共振和手性控制在同心纳米环先进自旋电子学应用

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-04-01 Epub Date: 2026-01-01 DOI: 10.1016/j.cjph.2025.12.035

Eduardo Saavedra , Ulises J. Guevara , Carlos Saji , Tamara González-Vega , Pablo Díaz , Laura M. Pérez

We investigate the spin-wave dynamics in concentric magnetic nanotori through micromagnetic simulations under perpendicular pulsed magnetic fields, using the free software MuMax3. These 3D nanostructures can host homochiral and heterochiral vortex configurations, whose spin-wave spectra strongly depend on the magnetostatic coupling parameter δ. In homochiral systems, resonance modes converge as δ increases, while in heterochiral systems, they diverge. Two distinct modes are identified: one associated with the outer surfaces of the tori and another with the inner torus. A central result is the demonstration of reversible transitions between homochiral and heterochiral vortex states using oscillating magnetic fields. The switching behavior and resonance properties vary with the coupling parameter δ, revealing the system’s dynamic versatility. This tunable chirality control positions concentric nanotori as promising candidates for future spintronic devices, enabling new opportunities for magnonic logic, non-volatile memory, and neuromorphic architectures. This work enhances the integration of 3D magnetic geometries with dynamic control, paving the way for applications in topological information processing and reconfigurable magnetic computing.

利用免费软件MuMax3，对垂直脉冲磁场下同心磁纳米环中的自旋波动力学进行了微磁模拟。这些三维纳米结构可以具有同手性和异手性涡旋构型，其自旋波谱强烈依赖于静磁耦合参数δ。在同手性体系中，共振模式随着δ的增大而收敛，而在异手性体系中，共振模式则发散。确定了两种不同的模式：一种与环面外表面相关，另一种与内环面相关。一个中心结果是用振荡磁场证明了在同手性和异手性涡旋态之间的可逆转变。开关行为和谐振特性随耦合参数δ的变化而变化，揭示了系统的动态通用性。这种可调的手性控制使同心纳米环成为未来自旋电子器件的有希望的候选器件，为磁逻辑、非易失性存储器和神经形态架构提供了新的机会。这项工作增强了三维磁几何与动态控制的集成，为拓扑信息处理和可重构磁计算的应用铺平了道路。

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引用次数: 0

Multifield modulation of electronic structure in MoSi2N4/GeI2 van der Waals heterostructures MoSi2N4/GeI2范德华异质结构中电子结构的多场调制

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-04-01 Epub Date: 2025-12-26 DOI: 10.1016/j.cjph.2025.12.028

Yuanlei Zhao, Xuewen Wang, Yingying Zhao, Ting Zhu, Zhaoming Fu, Syed Awais Ahmad, Weibin Zhang, Quanhong Ou

Through first-principles calculations, we systematically explored the evolution of the electronic structure of MoSi₂N₄/GeI₂ van der Waals heterostructure (vdWH) under biaxial strain, interlayer separation, and externally applied perpendicular electric fields. The pristine vdWH emerges as a direct-gap semiconductor with a bandgap of 1.69 eV. A compressive strain of 4% increases the bandgap to a maximum of 2.23 eV, whereas a tensile strain induces a precipitous reduction to 0.63 eV at 8%. Variations in interlayer spacing exert an equally pronounced influence: the bandgap broadens to 1.83 eV at 3.06 Å, but collapses abruptly to 0.16 eV upon further contraction to 1.56 Å. Perpendicular E-fields provide an additional lever of control; a modest field of -0.1 V Å^-1 elevates the bandgap to 1.85 eV, while stronger fields of -0.5 V Å^-1 quench the gap entirely, driving the system into a metallic state. The underlying mechanisms governing these bandgap modulations are elucidated in detail. Collectively, these results highlight the remarkable tunability of MoSi₂N₄/GeI₂ vdWH, thereby providing a theoretical framework for the rational conception of next-generation devices in the optoelectronic and flexible electronic domains.

通过第一性原理计算，系统地探讨了MoSi2N4/GeI2范德华异质结构（vdWH）在双轴应变、层间分离和外加垂直电场作用下的电子结构演变。原始vdWH以带隙1.69 eV的直接隙半导体形式出现。当压缩应变为4%时，带隙增大到2.23 eV的最大值，而当拉伸应变为8%时，带隙急剧减小到0.63 eV。层间间距的变化也会产生同样明显的影响：在3.06 Å时，带隙变宽至1.83 eV，但在进一步收缩至1.56 Å时，带隙突然坍缩至0.16 eV。垂直的电场提供了额外的控制杠杆；适度的电场-0.1 V Å-1将带隙提升到1.85 eV，而更强的电场-0.5 V Å-1将带隙完全淬灭，使系统进入金属状态。详细阐明了控制这些带隙调制的基本机制。总的来说，这些结果突出了MoSi2N4/GeI2 vdWH的显著可调性，从而为光电和柔性电子领域的下一代器件的合理概念提供了理论框架。

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引用次数: 0

Stellar modeling within regularized 4D Einstein-Gauss-Bonnet gravity in light of current astrophysical constraints 基于当前天体物理约束的正则四维爱因斯坦-高斯-邦尼引力下的恒星建模

IF 4.6 2区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Chinese Journal of Physics

Pub Date : 2026-04-01 Epub Date: 2025-12-31 DOI: 10.1016/j.cjph.2025.12.037

Grigorios Panotopoulos , Ángel Rincón , Ilidio Lopes

In this study we obtain interior solutions and investigate structural properties of isotropic compact stars in the framework of four-dimensional regularized Einstein-Gauss-Bonnet (4DEGB) gravity. For stellar matter content, we adopt a widely used quark-matter model that approximates a realistic equation of state (EoS). By numerically integrating the modified Tolman-Oppenheimer-Volkoff equations, we obtain interior solutions for static, spherically symmetric fluid spheres. The resulting sequences are compared directly with the predictions of General Relativity (GR). Our analysis focuses on three diagnostic indicators: (i) the mass-radius profiles under GR and three representative choices of the Gauss-Bonnet coupling; (ii) the stellar compactness factor, C ≡ M/R; and (iii) the relation between stellar mass and central energy density. Recent observational studies suggest that the maximum masses inferred from the mass-radius relation may be larger than previously expected. To address this, we include a comparative set of constraints from multi-messenger astrophysical observations, including gravitational-wave event GW190814, as well as X-ray measurements from NICER for PSR J0740+6620 and PSR J0030+0451. These data provide stringent, astrophysically grounded tests of the viability of the models discussed here. Our results indicate that compact stars within 4DEGB gravity are systematically less compact and achieve moderately higher maximum masses compared to the GR case. This trend is consistent with recent theoretical analyses of compact stars in higher-curvature gravity theories and with constraints from multi-messenger astrophysics. Together, these findings suggest that regularized Gauss-Bonnet corrections constitute a plausible extension of GR in the strong-field regime.

本文在四维正则einstein - gas - bonnet （4DEGB）引力框架下，研究了各向同性致密星的内部解和结构性质。对于恒星物质含量，我们采用了一种广泛使用的夸克-物质模型，该模型近似于现实的状态方程（EoS）。通过对修正的Tolman-Oppenheimer-Volkoff方程进行数值积分，得到了静力球对称流体球的内部解。结果序列直接与广义相对论（GR）的预测进行比较。本文重点分析了三个诊断指标：(1)GR下的质量半径分布和高斯-邦纳耦合的三种代表性选择；（ii）恒星紧凑系数C ≡ M/R；(3)恒星质量与中心能量密度的关系。最近的观测研究表明，从质量-半径关系推断出的最大质量可能比先前预期的要大。为了解决这个问题，我们包括了一组来自多信使天体物理观测的比较约束，包括引力波事件GW190814，以及NICER对PSR J0740+6620和PSR J0030+0451的x射线测量。这些数据为这里讨论的模型的可行性提供了严格的、基于天体物理学的检验。我们的研究结果表明，与GR情况相比，重力在4DEGB以内的致密恒星系统上更不致密，最大质量也更高。这一趋势与最近在高曲率引力理论中对致密恒星的理论分析以及多信使天体物理学的约束是一致的。总之，这些发现表明，正则化高斯-博内修正构成了强场状态下广义相对论的合理扩展。

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引用次数: 0