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Massless Dirac perturbations of black holes in f(Q) gravity: quasinormal modes and a weak deflection angle f(Q)引力中黑洞的无质量狄拉克扰动:准正常模式和弱偏转角
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-18 DOI: 10.1088/1572-9494/ad51ee
Ahmad Al-Badawi and Sohan Kumar Jha
This article considers a static and spherical black hole (BH) in f(Q) gravity. f(Q) gravity is the extension of symmetric teleparallel general relativity, where both curvature and torsion are vanishing and gravity is described by nonmetricity. In this study, we investigate the possible implications of quasinormal mode (QNM) modified Hawking spectra and deflection angles generated by the model. The Wentzel–Kramers–Brillouin method is used to solve the equations of motion for massless Dirac perturbation fields and explore the impact of the nonmetricity parameter (Q0). Based on the QNM computation, we can ensure that the BH is stable against massless Dirac perturbations and as Q0 increases the oscillatory frequency of the mode decreases. We then discuss the weak deflection angle in the weak field limit approximation. We compute the deflection angle up to the fourth order of approximation and show how the nonmetricity parameter affects it. We find that the Q0 parameter reduces the deflection angle.
f(Q) 引力是对称远平行广义相对论的扩展,其中曲率和扭转都是消失的,引力是用非度量描述的。在这项研究中,我们探讨了该模型产生的准正常模式(QNM)修正霍金谱和偏转角可能产生的影响。我们采用文采尔-克拉默斯-布里渊方法求解无质量狄拉克扰动场的运动方程,并探索非对称性参数(Q0)的影响。基于 QNM 计算,我们可以确保 BH 在面对无质量狄拉克扰动时是稳定的,并且随着 Q0 的增加,模式的振荡频率会降低。然后,我们讨论弱场极限近似中的弱偏转角。我们计算了四阶近似以内的偏转角,并展示了非度量参数对它的影响。我们发现 Q0 参数会减小偏转角。
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引用次数: 0
Light axion-like particles and the pseudoscalar mesonic decays M⃗M′νν¯ 类轴子轻粒子和伪标量介子衰变 M⃗M′νν¯
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-16 DOI: 10.1088/1572-9494/ad5277
Guo-Qiang Dai, Chong-Xing Yue, Yang-Yang Bu and Yi-Hang Wang
The axion-like particle (ALP) is one kind of the best-motivated new particles. We consider its production from the pseudoscalar mesonic decays , with M being a pseudoscalar meson B or K. The upper limits on the flavor-conserving ALP–quark coupling parameter gu are obtained by assuming the ALP to be an invisible particle. We find that the most severe constraint on gu comes from the decay for 0.05 GeV ≤ Ma ≤ 0.35 GeV, while the decays and can also generate significant constraints.
类轴子粒子(ALP)是一种最有动机的新粒子。我们考虑了它从伪星介子衰变中产生的问题,其中M是伪星介子B或K。我们假定ALP是一个看不见的粒子,从而得到了保持味道的ALP-夸克耦合参数gu的上限。我们发现,0.05 GeV ≤ Ma ≤ 0.35 GeV衰变对gu的约束最严重,而和衰变也会产生重要的约束。
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引用次数: 0
Constant-roll inflation with non-minimally derivative coupling 具有非微量导数耦合的恒定滚动膨胀
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-16 DOI: 10.1088/1572-9494/ad51ef
Jie Liu, Yungui Gong and Zhu Yi
We investigate the constant-roll inflation with non-minimally kinetic coupling to the Einstein tensor. With the slow-roll parameter being a constant, we calculate the power spectra for scalar and tensor perturbations, and derive the expressions for the scalar spectral tilt ns, the tensor spectral tilt nT, and the tensor-to-scalar ratio r. We find that the expressions for ns are different with different ordering of taking the derivative of the scalar power spectrum with respect to the scale k and the horizon crossing condition csk = aH in the constant-roll inflation, the consistency relation r = − 8nT does not hold if ∣ηϕ∣ is not small, and the duality of the tensor-to-scalar ratio between the slow-roll inflation and ultra-slow-roll inflation does not exist in inflationary models with non-minimally derivative coupling. The result offers a fresh perspective on the understanding of the inflationary models with non-minimally derivative coupling and is helpful for the production of scalar induced gravitational waves in the framework of ultra-slow-roll inflation with non-minimally derivative coupling.
我们研究了与爱因斯坦张量具有非最小动能耦合的恒定滚动膨胀。在慢滚参数为常数的情况下,我们计算了标量和张量扰动的功率谱,并推导出标量谱倾斜 ns、张量谱倾斜 nT 以及张量与标量之比 r 的表达式。我们发现,在恒定滚动膨胀中,标量功率谱相对于尺度k的导数和地平线穿越条件tsk = aH的不同取序下,ns的表达式不同;如果∣η∣j不小,一致性关系r = - 8nT不成立;在非微导数耦合的膨胀模型中,慢滚动膨胀和超慢滚动膨胀的张量与标量比的二元性不存在。该结果为理解具有非微分导数耦合的膨胀模型提供了一个全新的视角,并有助于在具有非微分导数耦合的超慢卷膨胀框架下产生标量诱导引力波。
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引用次数: 0
Efficient fidelity estimation: alternative derivation and related applications 高效保真度估算:替代推导及相关应用
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-16 DOI: 10.1088/1572-9494/ad5664
Diego S Starke, Marcos L W Basso and Jonas Maziero
In [Phys. Rev. A107 012427 (2023)], Baldwin and Jones prove that Uhlmann–Jozsa’s fidelity between two quantum states ρ and σ, i.e., , can be written in a simplified form as . In this article, we give an alternative proof of this result, using a function power series expansion and the properties of the trace function. Our approach not only reinforces the validity of the simplified expression but also facilitates the exploration of novel dissimilarity functions for quantum states and more complex trace functions of density operators.
在[Phys. Rev. A107 012427 (2023)]中,鲍德温和琼斯证明 Uhlmann-Jozsa 的两个量子态 ρ 和 σ 之间的保真度,即 ,可以简化为 。在本文中,我们利用函数幂级数展开和迹函数的特性,给出了这一结果的另一种证明。我们的方法不仅加强了简化表达式的有效性,还有助于探索量子态的新异函数和密度算子更复杂的迹函数。
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引用次数: 0
Tidal effects based on a GUP-induced effective metric 基于 GUP 引起的有效度量的潮汐效应
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-16 DOI: 10.1088/1572-9494/ad51f0
Soon-Tae Hong, Yong-Wan Kim and Young-Jai Park
In this paper, we study tidal forces in the Schwarzschild black hole, whose metric explicitly includes a generalized uncertainty principle (GUP) effect. We also investigate interesting features of the geodesic equations and tidal effects that are dependent on the GUP parameter α related to a minimum length. Then, by solving the geodesic deviation equations explicitly with appropriate boundary conditions, we show that α in the effective metric affects both the radial and angular components of the geodesic equation, particularly near the singularities.
在本文中,我们研究了施瓦兹柴尔德黑洞中的潮汐力,其公设明确包含广义不确定性原理(GUP)效应。我们还研究了与最小长度相关的 GUP 参数 α 有关的大地方程和潮汐效应的有趣特征。然后,通过用适当的边界条件显式求解大地偏离方程,我们表明有效度量中的α会影响大地方程的径向和角向分量,尤其是在奇点附近。
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引用次数: 0
Evolution of light deflection and shadow from a gauge-potential-like AdS black hole under the influence of a non-magnetic plasma medium 非磁等离子体介质影响下的规势样 AdS 黑洞的光偏转和光影演变
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-16 DOI: 10.1088/1572-9494/ad51f1
Riasat Ali, Xia Tiecheng, Muhammad Awais and Rimsha Babar
We investigate the light deflection in the weak field approximation from the accelerating charged AdS black hole. For this purpose, we apply the Gauss–Bonnet theorem to calculate the light deflection in the weak field area and use the Gibbons–Werner approach to analyze the optical geometry of the accelerating charged AdS black hole in the non-magnetic plasma absence/presence of a non-magnetic medium. We also represent the graphical behavior of the light deflection angle w.r.t. the impact parameter. We also compute the light deflection angle using Keeton and Petters approximations under the impact of accelerating charged AdS black hole geometry. Furthermore, by using the ray-tracing approach, we determine the shadow in the non-magnetic plasma presence and also demonstrate that graphical shadow has an impact on the gauge potential, non-magnetic plasma frequencies and charge.
我们研究了加速带电AdS黑洞在弱场近似中的光偏转。为此,我们应用高斯-波内特定理计算弱场区域的光偏转,并使用吉本斯-维尔纳方法分析加速带电 AdS 黑洞在没有/存在非磁性介质的非磁性等离子体中的光学几何。我们还用图形表示了光偏转角随撞击参数的变化。我们还利用基顿和彼得斯近似计算了加速带电 AdS 黑洞几何撞击下的光偏转角。此外,通过射线追踪方法,我们确定了非磁性等离子体中存在的阴影,并证明了图形阴影对规势、非磁性等离子体频率和电荷的影响。
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引用次数: 0
Slowly rotating charges from Weyl double copy for Kerr black hole with Chern–Simons correction 带有切尔-西蒙斯修正的克尔黑洞韦尔双副本慢旋转电荷
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-04 DOI: 10.1088/1572-9494/ad4a37
Yi-Ran Liu, Jing-Rui Zhang and Yun-Long Zhang
The Weyl double copy builds the relation between gauge theory and gravity theory, in particular the correspondence between gauge solutions and gravity solutions. In this paper, we obtain the slowly rotating charge solutions from the Weyl double copy for the Kerr black hole with small Chern–Simons correction. Based on the Weyl double copy relation, for the Petrov type D solution in Chern–Simons modified gravity, we find the additional correction to the electromagnetic field strength tensor of the rotating charge. For the Petrov type I solution, we find that the additional electromagnetic field strength tensors have external sources, while the total sources vanish at the leading order.
韦尔双副本建立了规理论与引力理论之间的关系,特别是规解与引力解之间的对应关系。在本文中,我们从韦尔双副本中得到了具有小切尔西蒙修正的克尔黑洞的慢旋转电荷解。根据韦尔双拷贝关系,对于切尔-西蒙斯修正引力中的彼得罗夫 D 型解,我们找到了旋转电荷的电磁场强度张量的附加修正。对于彼得罗夫 I 型解,我们发现附加电磁场强度张量有外部源,而总源在前导阶消失。
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引用次数: 0
An approximate Kerr–Newman-like metric endowed with a magnetic dipole and mass quadrupole 具有磁偶极子和质量四极子的近似克尔-纽曼类方程
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-04 DOI: 10.1088/1572-9494/ad4cde
Francisco Frutos-Alfaro
Approximate all-terrain spacetimes for astrophysical applications are presented. The metrics possess five relativistic multipole moments, namely, mass, rotation, mass quadrupole, charge, and magnetic dipole moment. All these spacetimes approximately satisfy the Einstein–Maxwell field equations. The first metric is generated using the Hoenselaers–Perjés method from given relativistic multipoles. The second metric is a perturbation of the Kerr–Newman metric, which makes it a relevant approximation for astrophysical calculations. The last metric is an extension of the Hartle–Thorne metric that is important for obtaining internal models of compact objects perturbatively. The electromagnetic field is calculated using Cartan forms for locally non-rotating observers. These spacetimes are relevant for inferring properties of compact objects from astrophysical observations. Furthermore, the numerical implementations of these metrics are straightforward, making them versatile for simulating potential astrophysical applications.
介绍了天体物理学应用的近似全地形时空。这些度量具有五个相对论多极矩,即质量、旋转、质量四极、电荷和磁偶极矩。所有这些时空都近似满足爱因斯坦-麦克斯韦场方程。第一个度量是用霍恩斯拉尔-佩尔杰斯方法从给定的相对论多极矩生成的。第二个度量是克尔-纽曼度量的扰动,这使其成为天体物理计算的相关近似值。最后一个度量是哈特尔-索恩度量的扩展,对于获得紧凑天体的内部扰动模型非常重要。电磁场是利用局部非旋转观测器的 Cartan 形式计算出来的。这些时空对于从天体物理观测中推断紧凑天体的性质非常重要。此外,这些度量的数值实现非常简单,使它们成为模拟潜在天体物理应用的多功能工具。
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引用次数: 0
Shell-model representations of the microscopic version of the Bohr–Mottelson collective model 玻尔-莫特森集体模型微观版本的壳模型表示法
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-04 DOI: 10.1088/1572-9494/ad4c56
H G Ganev
The structure of the irreducible collective spaces of the group Sp(12, R), which many-particle nuclear states are classified according to the chain Sp(12, R) ⊃ U(6) ⊃ SO(6) ⊃ SUpn(3) ⨂ SO(2) ⊃ SO(3) of the proton–neutron symplectic model (PNSM), is considered in detail. This chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr–Mottelson collective model. The construction of the relevant shell-model representations of the Sp(12, R) group along this chain is considered for three nuclei with varying collective properties and from different mass regions. It is shown that the SUpn(3) basis states of the Sp(12, R) representations belonging to the SO(6) irreps with seniority υ ≥ υ0, with υ0 denoting the maximal seniority SO(6) irrep contained in the Sp(12, R) bandhead, are always Pauli allowed, but organized in a different way into different SO(6) shells. This is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm operation. Although the SUpn(3) multiplets within υ < υ0 are not all Pauli forbidden, it is safe to discard them. The results obtained in the present work are important for the practical application of the microscopic version of the Bohr–Mottelson collective model.
本文详细研究了 Sp(12,R)组的不可还原集合空间的结构,其中多粒子核态是根据质子-中子交义模型(PNSM)的链 Sp(12, R) ⊃ U(6) ⊃ SO(6) ⊃ SUpn(3) ⨂ SO(2) ⊃ SO(3) 进行分类的。质子-中子交义模型的这一链条最近被证明对应于玻尔-莫特森集体模型的微观壳模型版本。针对三个具有不同集体性质和来自不同质量区域的原子核,我们考虑了沿着这条链构建 Sp(12, R) 群的相关壳模型表示。结果表明,Sp(12, R)表示中属于SO(6)反演的SUpn(3)基态具有阶数υ ≥ υ0,υ0表示Sp(12, R)带头中包含的最大阶数SO(6)反演,它们总是保利允许的,但以不同的方式组织成不同的SO(6)壳。这与填充标准三维谐振子的水平并使用褶皱操作的情况截然不同。虽然υ < υ0内的SUpn(3)多重子并不都是保利禁止的,但舍弃它们是安全的。本研究获得的结果对于玻尔-莫特森集体模型微观版本的实际应用具有重要意义。
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引用次数: 0
Discrete Boltzmann model with split collision for nonequilibrium reactive flows* 非平衡态反应流的分裂碰撞离散玻尔兹曼模型*
IF 3.1 3区 物理与天体物理 Q2 PHYSICS, MULTIDISCIPLINARY Pub Date : 2024-07-04 DOI: 10.1088/1572-9494/ad4a36
Chuandong Lin, Kai H Luo and Huilin Lai
A multi-relaxation-time discrete Boltzmann model (DBM) with split collision is proposed for both subsonic and supersonic compressible reacting flows, where chemical reactions take place among various components. The physical model is based on a unified set of discrete Boltzmann equations that describes the evolution of each chemical species with adjustable acceleration, specific heat ratio, and Prandtl number. On the right-hand side of discrete Boltzmann equations, the collision, force, and reaction terms denote the change rates of distribution functions due to self- and cross-collisions, external forces, and chemical reactions, respectively. The source terms can be calculated in three ways, among which the matrix inversion method possesses the highest physical accuracy and computational efficiency. Through Chapman–Enskog analysis, it is proved that the DBM is consistent with the reactive Navier–Stokes equations, Fick's law and the Stefan–Maxwell diffusion equation in the hydrodynamic limit. Compared with the one-step-relaxation model, the split collision model offers a detailed and precise description of hydrodynamic, thermodynamic, and chemical nonequilibrium effects. Finally, the model is validated by six benchmarks, including multicomponent diffusion, mixture in the force field, Kelvin–Helmholtz instability, flame at constant pressure, opposing chemical reaction, and steady detonation.
针对各种成分之间发生化学反应的亚音速和超音速可压缩反应流,提出了一种具有分裂碰撞的多松弛时间离散玻尔兹曼模型(DBM)。该物理模型基于一组统一的离散玻尔兹曼方程,描述了每种化学物质在可调加速度、比热比和普朗特尔数条件下的演变过程。在离散玻尔兹曼方程的右侧,碰撞项、力项和反应项分别表示自碰撞和交叉碰撞、外力和化学反应导致的分布函数变化率。源项有三种计算方法,其中矩阵反演法具有最高的物理精度和计算效率。通过 Chapman-Enskog 分析,证明了 DBM 与反应 Navier-Stokes 方程、Fick 定律和流体力学极限下的 Stefan-Maxwell 扩散方程是一致的。与一步松弛模型相比,分裂碰撞模型能详细而精确地描述流体力学、热力学和化学非平衡态效应。最后,该模型通过六个基准进行了验证,包括多组分扩散、力场中的混合物、开尔文-赫尔姆霍兹不稳定性、恒压火焰、对立化学反应和稳定引爆。
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引用次数: 0
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Communications in Theoretical Physics
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