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A Comprehensive Study on the Mid-Infrared Variability of Blazars 关于蓝星中红外变异性的综合研究
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-07 DOI: 10.3390/universe10090360
Xuemei Zhang, Zhipeng Hu, Weitian Huang, Lisheng Mao
We present a comprehensive investigation of mid-infrared (MIR) flux variability at 3.4 μm (W1 band) for a large sample of 3816 blazars, using Wide-field Infrared Survey Explorer (WISE) data through December 2022. The sample consists of 1740 flat-spectrum radio quasars (FSRQs), 1281 BL Lac objects (BL Lacs), and 795 blazars of uncertain type (BCUs). Considering Fermi Large Area Telescope detection, we classify 2331 as Fermi blazars and 1485 as non-Fermi blazars. Additionally, based on synchrotron peak frequency, the sample includes 2264 low-synchrotron peaked (LSP), 512 intermediate-synchrotron peaked (ISP), and 655 high-synchrotron peaked (HSP) sources. We conduct a comparative analysis of short- and long-term intrinsic variability amplitude (σm), duty cycle (DC), and ensemble structure function (ESF) across blazar subclasses. The median short-term σm values were 0.181−0.106+0.153, 0.104−0.054+0.101, 0.135−0.076+0.154, 0.173−0.097+0.158, 0.177−0.100+0.156, 0.096−0.050+0.109, and 0.106−0.058+0.100 mag for FSRQs, BL Lacs, Fermi blazars, non-Fermi blazars, LSPs, ISPs, and HSPs, respectively. The median DC values were 71.03−22.48+14.17, 64.02−22.86+16.97, 68.96−25.52+15.66, 69.40−22.17+14.42, 71.24−21.36+14.25, 63.03−33.19+16.93, and 64.63−24.26+15.88 percent for the same subclasses. The median long-term σm values were 0.137−0.105+0.408, 0.171−0.132+0.206, 0.282−0.184+0.332, 0.071−0.062+0.143, 0.218−0.174+0.386, 0.173−0.132+0.208, and 0.101−0.077+0.161 mag for the same subclasses, respectively. Our results reveal significant differences in 3.4 μm flux variability among these subclasses. FSRQs (LSPs) exhibit larger σm and DC values compared to BL Lacs (ISPs and HSPs). Fermi blazars display higher long-term σm but lower short-term σm relative to non-Fermi blazars, while DC distributions between the two groups are similar. ESF analysis further confirms the greater variability of FSRQs, LSPs, and Fermi blazars across a wide range of time scales compared to BL Lacs, ISPs/HSPs, and non-Fermi blazars. These findings highlight a close correlation between MIR variability and blazar properties, providing valuable insights into the underlying physical mechanisms responsible for their emission.
我们利用宽视场红外巡天探测器(WISE)截至 2022 年 12 月的数据,对 3816 个炽星大样本在 3.4 μm(W1 波段)的中红外(MIR)通量变异性进行了全面研究。样本包括 1740 个平谱射电类星体(FSRQs)、1281 个 BL Lac 天体(BL Lacs)和 795 个不确定类型的类星体(BCUs)。考虑到费米大面积望远镜的探测结果,我们将2331颗类星体归类为费米类星体,1485颗类星体归类为非费米类星体。此外,根据同步辐射峰频率,样本包括 2264 个低同步辐射峰源(LSP)、512 个中同步辐射峰源(ISP)和 655 个高同步辐射峰源(HSP)。我们对各类星体的短期和长期本征变率振幅(σm)、占空比(DC)和集合结构函数(ESF)进行了比较分析。短期 σm 的中值分别为 0.181-0.106+0.153、0.104-0.054+0.101、0.135-0.076+0.154、0.173-0.097+0.158、0.177-0.100+0.156,0.096-0.050+0.109,以及0.106-0.058+0.100 mag,分别用于FSRQs、BL Lacs、费米类星体、非费米类星体、LSPs、ISPs和HSPs。同一亚类的DC中值分别为71.03-22.48+14.17、64.02-22.86+16.97、68.96-25.52+15.66、69.40-22.17+14.42、71.24-21.36+14.25、63.03-33.19+16.93和64.63-24.26+15.88%。同一亚类的长期σm 中值分别为 0.137-0.105+0.408、0.171-0.132+0.206、0.282-0.184+0.332、0.071-0.062+0.143、0.218-0.174+0.386、0.173-0.132+0.208 和 0.101-0.077+0.161 兆。我们的研究结果表明,这些亚类在 3.4 μm 通量变异性方面存在明显差异。与 BL Lacs(ISPs 和 HSPs)相比,FSRQs(LSPs)表现出更大的σm 和 DC 值。与非费米星相比,费米星的长期σm较高,但短期σm较低,而两组之间的DC分布相似。ESF分析进一步证实,与BL Lacs、ISPs/HSPs和非费米星相比,FSRQs、LSPs和费米星在广泛的时间尺度上具有更大的可变性。这些发现凸显了近红外变率与类星体特性之间的密切联系,为我们深入了解类星体发射的基本物理机制提供了宝贵的信息。
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引用次数: 0
Probing the Nonlinear Density Wave Theory of Spiral Galaxies by Baryonic Tully–Fisher Relation 用重子塔利-费舍尔关系探测螺旋星系的非线性密度波理论
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-06 DOI: 10.3390/universe10090359
Miroslava Vukcevic, Djordje Savic, Predrag Jovanović
The baryonic mass–velocity relation provides an important test of different galaxy dynamics models such as Lambda–cold dark matter (ΛCDM) and alternatives like Modified Newtonian Dynamics (MOND). Novel nonlinear density wave theory with a soliton solution gives an opportunity to test whether the derived rotational velocity expression is able to support the well known Tully–Fisher empirical relation between mass and rotation velocity in disk galaxies. Initial assumptions do not involve any larger dark matter halo that supports the stability of the very thin galactic disk nor any modified gravitational acceleration acting on galactic scales. It rather follows an important gravitational interaction between constituents of disk mass in the outer part of the disk via gravitational potential. Data are obtained by a fitting procedure applied on the sample of 81 rotational curves of late type spirals using expressions for the rotational velocity derived as an exact, a self-consistent solution of the nonlinear Schrodinger (NLS) equation for galactic surface mass density. The location of these selected objects in the baryonic mass–rotation velocity plane follows the relation logMb=3.7±0.2logVflat+2.7±0.4 in marginal agreement with the findings in the literature.
重子质量-速度关系是对不同星系动力学模型(如兰姆达-冷暗物质(ΛCDM)和修正牛顿动力学(MOND)等替代模型)的重要检验。带有孤子解的新颖非线性密度波理论提供了一个机会,检验推导出的旋转速度表达式是否能够支持盘状星系质量与旋转速度之间众所周知的塔利-费舍经验关系。最初的假设不涉及任何支持极薄星系盘稳定性的较大暗物质晕,也不涉及任何作用于星系尺度的修正引力加速度。相反,在星系盘的外部,星系盘质量成分之间通过引力势发生了重要的引力相互作用。数据是通过对 81 条晚螺旋型旋转曲线样本的拟合程序获得的,拟合程序使用的是银河系表面质量密度非线性薛定谔方程(NLS)的自洽性精确解中得出的旋转速度表达式。这些选定天体在重子质量-旋转速度平面上的位置遵循 logMb=3.7±0.2logVflat+2.7±0.4 的关系,与文献中的发现基本一致。
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引用次数: 0
Three-Dimensional Quantum Black Holes: A Primer 三维量子黑洞:入门指南
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-06 DOI: 10.3390/universe10090358
Emanuele Panella, Juan F. Pedraza, Andrew Svesko
We review constructions of three-dimensional ‘quantum’ black holes. Such spacetimes arise via holographic braneworlds and are exact solutions to an induced higher-derivative theory of gravity consistently coupled to a large-c quantum field theory with an ultraviolet cutoff, accounting for all orders of semi-classical backreaction. Notably, such quantum-corrected black holes are much larger than the Planck length. We describe the geometry and horizon thermodynamics of a host of asymptotically (anti-) de Sitter and flat quantum black holes. A summary of higher-dimensional extensions is given. We survey multiple applications of quantum black holes and braneworld holography.
我们回顾了三维 "量子 "黑洞的构造。这种时空是通过全息支世界产生的,是引力的诱导高阶衍生理论的精确解,与具有紫外截止的大c量子场论一致耦合,考虑了所有阶次的半经典反作用。值得注意的是,这种量子修正的黑洞比普朗克长度大得多。我们描述了一系列渐近(反)德西特黑洞和平面量子黑洞的几何和视界热力学。我们还总结了量子黑洞的高维扩展。我们考察了量子黑洞和支界全息的多种应用。
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引用次数: 0
Non-Canonical Dark Energy Parameter Evolution in a Canonical Quintessence Cosmology 经典五元宇宙学中的非经典暗能量参数演化
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-05 DOI: 10.3390/universe10090356
Rodger I. Thompson
This study considers the specific case of a flat, minimally coupled to gravity, quintessence cosmology with a dark energy quartic polynomial potential that has the same mathematical form as the Higgs potential. Previous work on this case determined that the scalar field is given by a simple expression of the Lambert W function in terms of the easily observable scale factor. This expression provides analytic equations for the evolution of cosmological dark energy parameters as a function of the scale factor for all points on the Lambert W function principal branch. The Lambert W function is zero at a scale factor of zero that marks the big bang. The evolutionary equations beyond the big bang describe a canonical universe that is similar to ΛCDM, making it an excellent dynamical template to compare with observational data. The portion of the W function principal before the big bang extends to the infinite pre-bang past. It describes a noncanonical universe with an initially very low mass density that contracts by rolling down the dark energy potential to a singularity, big bang, at the scale factor zero point. This provides a natural origin for the big bang. It also raises the possibility that the universe existed before the big bang and is far older, and that it was once far larger than its current size. The recent increasing interest in the possibility of a dynamical universe instead of ΛCDM makes the exploration of the nature of such universes particularly relevant.
本研究考虑的是平坦、与引力耦合最小、具有暗能量四元多项式势的五元宇宙学的具体情况,其数学形式与希格斯势相同。以前关于这种情况的研究确定,标量场是由易于观测的尺度因子的朗伯 W 函数的简单表达式给出的。这个表达式为宇宙学暗能量参数的演化提供了解析方程,它是兰伯特 W 函数主支上所有点的尺度因子的函数。兰伯特 W 函数在大爆炸的尺度因子为零时为零。大爆炸之后的演化方程描述了一个与ΛCDM 相似的典型宇宙,使其成为与观测数据进行比较的绝佳动力学模板。大爆炸之前的 W 函数本构部分一直延伸到大爆炸之前的无限过去。它描述了一个非正则宇宙,其初始质量密度非常低,通过暗能量势能向下滚动收缩,在尺度因子零点形成奇点,即大爆炸。这为大爆炸提供了一个自然起源。这也提出了一种可能性,即宇宙在大爆炸之前就已经存在,而且要古老得多,它曾经比现在的大小要大得多。最近,人们越来越关注用动力学宇宙代替ΛCDM的可能性,这使得探索这种宇宙的性质变得尤为重要。
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引用次数: 0
Exploring New Physics with Deep Underground Neutrino Experiment High-Energy Flux: The Case of Lorentz Invariance Violation, Large Extra Dimensions and Long-Range Forces 利用深层地下中微子实验高能通量探索新物理:洛伦兹不变量违反、大超维空间和远距离力的情况
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-05 DOI: 10.3390/universe10090357
Alessio Giarnetti, Simone Marciano, Davide Meloni
DUNE is a next-generation long-baseline neutrino oscillation experiment. It is expected to measure, with unprecedented precision, the atmospheric oscillation parameters, including the CP-violating phase δCP. Moreover, several studies have suggested that its unique features should allow DUNE to probe several new physics scenarios. In this work, we explore the performances of the DUNE far detector in constraining new physics if a high-energy neutrino flux is employed (HE-DUNE). We take into account three different scenarios: Lorentz Invariance Violation (LIV), Long-Range Forces (LRFs) and Large Extra Dimensions (LEDs). Our results show that HE-DUNE should be able to set bounds competitive to the current ones and, in particular, it can outperform the standard DUNE capabilities in constraining CPT-even LIV parameters and the compactification radius RED of the LED model.
DUNE 是下一代长基线中微子振荡实验。它有望以前所未有的精度测量大气振荡参数,包括违反 CP 的阶段 δCP。此外,一些研究表明,DUNE 的独特功能应该能够探测到一些新的物理情景。在这项工作中,我们探讨了如果采用高能中微子通量(HE-DUNE),DUNE 远探测器在约束新物理学方面的性能。我们考虑了三种不同的情况:洛伦兹不变量违反(LIV)、长程力(LRFs)和大超维(LEDs)。我们的研究结果表明,HE-DUNE应该能够设定与当前模型具有竞争力的边界,特别是在约束CPT-even LIV参数和LED模型的压缩半径RED方面,它可以超越标准DUNE的能力。
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引用次数: 0
Quantum Loop Corrections in the Modified Gravity Model of Starobinsky Inflation With Primordial Black Hole Production 有原始黑洞产生的斯塔罗宾斯基膨胀修正引力模型中的量子环校正
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-04 DOI: 10.3390/universe10090354
Sultan Saburov, Sergei V. Ketov
A modified gravity model of Starobinsky inflation and primordial black hole production is proposed in good (within 1σ) agreement with current measurements of the cosmic microwave background radiation. The model is an extension of the singularity-free Appleby–Battye–Starobinsky model by the R4 term with different values of the parameters whose fine-tuning leads to the efficient production of primordial black holes on smaller scales with the asteroid-size masses between 1016 g and 1020 g. Those primordial black holes may be part (or the whole) of the current dark matter, while the proposed model can be confirmed or falsified by the detection or absence of the induced gravitational waves with the frequencies in the 10−2 Hz range. The relative size of quantum (loop) corrections to the power spectrum of scalar perturbations in the model is found to be of the order of 10−3 or less, so that the model is not ruled out by the quantum corrections.
提出了一个斯塔罗宾斯基暴胀和原始黑洞产生的修正引力模型,该模型与当前的宇宙微波背景辐射测量结果吻合良好(在 1σ 以内)。该模型是无奇点的阿普尔比-巴蒂-斯塔罗宾斯基模型的扩展,其中的R4项具有不同的参数值,其微调导致在更小的尺度上有效地产生原始黑洞,其质量在1016克到1020克之间,为小行星大小。这些原始黑洞可能是当前暗物质的一部分(或全部),而所提出的模型可以通过探测或不探测频率在10-2赫兹范围内的诱导引力波来证实或证伪。发现该模型中标量扰动功率谱的量子(环)修正的相对大小为 10-3 或更小,因此该模型并没有被量子修正所排除。
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引用次数: 0
4D Embedded Rotating Black Hole as a Particle Accelerator in the Presence of Magnetic Fields 存在磁场时作为粒子加速器的 4D 嵌入式旋转黑洞
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-04 DOI: 10.3390/universe10090355
Abraão J. S. Capistrano, Carlos Henrique Coimbra-Araújo, Rita de Cássia dos Anjos
We analyze a rotating black hole (BH) in a four-dimensional space-time embedded in five-dimensional flat bulk. In Boyer–Lindquist coordinates, we use a generic extension of the Kerr metric by the line element of Gürses–Gürsey metric. We discuss their horizon properties and shadow cast which is tailored by the influence of the extrinsic curvature. By means of the model based on the Nash–Greene theorem, we analyze the Gürses–Gürsey metric embedded in five dimensions acting as a rotating “charged” BH which may be regarded as a source of ultrahigh-energy cosmic rays (UHECRs). We also show that this type of BH presents a different structure of the accretion disk which is modified by the extrinsic curvature leading to an enlargement of the photons ring and an increase in the BH’s inner shadow. In the presence of a magnetic field, our initial results suggest that such BHs may be efficient free-test particle accelerators orbiting the inner stable circular orbit (ISCO).
我们分析了嵌入五维平面体的四维时空中的旋转黑洞(BH)。在博耶-林奎斯特坐标中,我们使用了由 Gürses-Gürsey 度量的线元对 Kerr 度量的一般扩展。我们讨论了它们的地平特性以及受外曲率影响而定制的阴影投射。通过基于纳什-格林(Nash-Greene)定理的模型,我们分析了嵌入五维空间的 Gürses-Gürsey 度量,它是一个旋转的 "带电 "BH,可被视为超高能宇宙射线(UHECRs)的来源。我们还证明,这种类型的 BH 呈现出不同的吸积盘结构,这种结构受到外在曲率的影响,导致光子环的扩大和 BH 内部阴影的增加。在存在磁场的情况下,我们的初步结果表明,这种 BH 可能是绕内稳定环形轨道(ISCO)运行的高效自由试验粒子加速器。
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引用次数: 0
Combined Studies Approach to Rule Out Cosmological Models Which Are Based on Nonlinear Electrodynamics 排除基于非线性电动力学的宇宙学模型的综合研究方法
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-04 DOI: 10.3390/universe10090353
Ricardo García-Salcedo, Isidro Gómez-Vargas, Tame González, Vicent Martinez-Badenes, Israel Quiros
We apply a combined study in order to investigate the dynamics of cosmological models incorporating nonlinear electrodynamics (NLED). The study is based on the simultaneous investigation of such fundamental aspects as stability and causality, complemented with a dynamical systems investigation of the involved models, as well as Bayesian inference for parameter estimation. We explore two specific NLED models: the power-law and the rational Lagrangian. We present the theoretical framework of NLED coupled with general relativity, followed by an analysis of the stability and causality of the various NLED Lagrangians. We then perform a detailed dynamical analysis to identify the ranges where these models are stable and causal. Our results show that the power-law Lagrangian model transitions through various cosmological phases, evolving from a Maxwell radiation-dominated state to a matter-dominated state. For the rational Lagrangian model, including the Maxwell term, stable and causal behavior is observed within specific parameter ranges, with critical points indicating the evolutionary pathways of the universe. To validate our theoretical findings, we perform Bayesian parameter estimation using a comprehensive set of observational data, including cosmic chronometers, baryon acoustic oscillation (BAO) measurements, and supernovae type Ia (SNeIa). The estimated parameters for both models align with the expected values for the current universe, particularly the matter density Ωm and the Hubble parameter h. However, the parameters of the models are not tightly constrained within the prior ranges. Our combined studies approach rules out the mentioned models as an appropriate description of the cosmos. Our results highlight the need for further refinement and exploration of NLED-based cosmological models to fully integrate them into the standard cosmological framework.
我们采用了一种综合研究方法来研究包含非线性电动力学(NLED)的宇宙学模型的动力学。这项研究基于对稳定性和因果关系等基本方面的同步研究,辅之以对相关模型的动力学系统研究,以及用于参数估计的贝叶斯推理。我们探讨了两个具体的 NLED 模型:幂律模型和理性拉格朗日模型。我们介绍了 NLED 与广义相对论耦合的理论框架,随后分析了各种 NLED 拉格朗日的稳定性和因果性。然后,我们进行了详细的动力学分析,以确定这些模型具有稳定性和因果性的范围。我们的结果表明,幂律拉格朗日模型经历了不同的宇宙学阶段,从麦克斯韦辐射主导状态演化到物质主导状态。对于包括麦克斯韦项在内的理性拉格朗日模型,在特定参数范围内观察到了稳定的因果行为,临界点表明了宇宙的演化路径。为了验证我们的理论发现,我们利用一整套观测数据进行了贝叶斯参数估计,包括宇宙计时器、重子声学振荡(BAO)测量和 Ia 型超新星(SNeIa)。两个模型的估计参数都符合当前宇宙的预期值,特别是物质密度ωm和哈勃参数h。我们的综合研究方法排除了上述模型对宇宙的适当描述。我们的研究结果强调了进一步完善和探索基于 NLED 的宇宙学模型的必要性,以便将它们完全纳入标准宇宙学框架。
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引用次数: 0
Different Aspects of Entropic Cosmology 熵宇宙学的不同方面
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-03 DOI: 10.3390/universe10090352
Shin’ichi Nojiri, Sergei D. Odintsov, Tanmoy Paul
We provide a short review of the recent developments in entropic cosmology based on two thermodynamic laws of the apparent horizon, namely the first and the second laws of thermodynamics. The first law essentially provides the change in entropy of the apparent horizon during the cosmic evolution of the universe; in particular, it is expressed by TdS=−d(ρV)+WdV (where W is the work density and other quantities have their usual meanings). In this way, the first law actually links various theories of gravity with the entropy of the apparent horizon. This leads to a natural question—“What is the form of the horizon entropy corresponding to a general modified theory of gravity?”. The second law of horizon thermodynamics states that the change in total entropy (the sum of horizon entropy + matter fields’ entropy) with respect to cosmic time must be positive, where the matter fields behave like an open system characterised by a non-zero chemical potential. The second law of horizon thermodynamics importantly provides model-independent constraints on entropic parameters. Finally, we discuss the standpoint of entropic cosmology on inflation (or bounce), reheating and primordial gravitational waves from the perspective of a generalised entropy function.
我们简要回顾了基于两个视界热力学定律(即热力学第一定律和第二定律)的熵宇宙学的最新发展。第一定律基本上提供了宇宙演化过程中视地平线的熵的变化;特别是,它用 TdS=-d(ρV)+WdV 表示(其中 W 是功密度,其他量具有通常的含义)。这样,第一定律实际上将各种引力理论与视界熵联系在了一起。这就自然引出了一个问题--"与一般修正引力理论相对应的视界熵的形式是什么?视界热力学第二定律指出,相对于宇宙时间,总熵(视界熵+物质场熵之和)的变化必须为正,其中物质场的行为就像一个开放系统,其特征是化学势不为零。地平线热力学第二定律为熵参数提供了与模型无关的重要约束。最后,我们从广义熵函数的角度,讨论了熵宇宙学关于暴胀(或反弹)、再热和原始引力波的观点。
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引用次数: 0
On the Classical Limit of Freely Falling Quantum Particles, Quantum Corrections and the Emergence of the Equivalence Principle 论自由落体量子粒子的经典极限、量子修正和等效原理的出现
IF 2.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS Pub Date : 2024-09-02 DOI: 10.3390/universe10090351
Juan A. Cañas, J. Bernal, A. Martín-Ruiz
Quantum and classical mechanics are fundamentally different theories, but the correspondence principle states that quantum particles behave classically in the appropriate limit. For high-energy periodic quantum systems, the emergence of the classical description should be understood in a distributional sense, i.e., the quantum probability density approaches the classical distribution when the former is coarse-grained. Following a simple reformulation of this limit in the Fourier space, in this paper, we investigate the macroscopic behavior of freely falling quantum particles. To illustrate how the method works and to fix some ideas, we first successfully apply it to the case of a particle in a box. Next, we show that, for a particle bouncing under the gravity field, in the limit of a high quantum number, the leading term of the quantum distribution corresponds to the exact classical distribution plus sub-leading corrections, which we interpret as quantum corrections at the macroscopic level.
量子力学和经典力学从根本上说是不同的理论,但对应原理指出,量子粒子在适当的限度内具有经典行为。对于高能周期量子系统,经典描述的出现应从分布的角度来理解,即当前者的分布粗粒度时,量子概率密度接近经典分布。本文通过在傅立叶空间对这一极限的简单重述,研究了自由下落量子粒子的宏观行为。为了说明该方法的工作原理并固定一些想法,我们首先成功地将其应用于一个盒子中的粒子的情况。接下来,我们证明,对于在引力场下反弹的粒子,在高量子数的极限下,量子分布的前导项对应于精确的经典分布加上次前导修正,我们将其解释为宏观层面的量子修正。
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引用次数: 0
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Universe
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