"广义芝诺悖论"的探讨

两辆相向匀速运动的车之间有一只小鸟,在两车间来回飞行.小鸟运动速率比车的要大,其初始位置是x0.当两车最终相遇时,相遇位置就是小鸟的最终位置.现在逆向演示(回放)该过程,即小鸟从两辆车相遇位置出发而两车作相背运动.当两车回到它们的初始位置时,小鸟将回到x0点.然而,在正过程中,由于两车相遇位置(即小鸟的最终位置)实际上和小鸟的初始位置无关,因此在逆过程中,小鸟最终可以处在任意位置而未必回到x0点.由此产生悖论,称做“广义芝诺悖论”.通过建立适当的物理模型,利用运动定律,分析并最终解决了这个悖论问题.     

量子芝诺效应的物理诠释探讨

本文试图从基本的量子力学规律出发,对测量问题中的量子芝诺现象进行分析和讨论,并分别结合一些经典实验和某些学派的解释,着重于动力学退相干模型,对其本身作出物理层面的诠释.     

一类广义Birkhoff系统的广义正则变换

研究一类广义Birkhoff系统的广义正则变换.建立这类广义Birkhoff系统的运动微分方程,得到了该系统的广义正则变换以及保持广义正则变换的条件.最后,举例说明结果的应用.     

古希腊思想的近代传承——原子论方法对经典物理学发展的影响

希腊是西方文明理性的源头和悖论的故乡,芝诺悖论对留基波和德谟克利特原子论方法的形成起到了推波助澜的作用,留基波和德谟克利特原子观念一直影响到一千多年以后科学家的思想方法,并在经典物理学发展历程中留下了不可磨灭的印记.正如20世纪最具创新能力的理论物理学家海森伯(Werner Karl Heisenberg,1901—1976)所言:"德谟克利特的原子观念成了上世纪物理学家唯物主义世界观不可缺少的组成部分,这种原子观念容易理解而且比较直观,它决定了物理学家的思想方法,甚至决定了那些不愿与哲学打交道的物理学家的思想方法."[1]     

基于复杂网络的电网结构健壮性及Braess悖论现象研究

应用复杂网络理论,建立电力系统的改进导纳模型,结合电网拓扑特性和电气特性对电网的级联故障进行研究.通过随机移除传输线引发电网级联故障,研究网络的节点数、平均度、发电站数量以及发电站的分布状况对系统健壮性的影响,并对小世界电网级联故障过程中的布雷斯(Braess)悖论现象进行分析.研究表明:网络的健壮性与其拓扑结构密切相...     

广义Birkhoff系统的两类广义梯度表示

提出了两类广义梯度系统, 即广义斜梯度系统以及具有对称负定矩阵的广义梯度系统. 分别讨论了这两类梯度系统与动力学系统稳定性的关系. 研究了广义Brikhoff系统的两类广义梯度表示, 分别给出条件和表达式. 给出了广义Brikhoff系统稳定性的梯度判别法, 利用广义梯度系统的性质来研究广义Birkhoff系统的稳定性. 并举例说明了方法的应用.     

"示波器的使用"实验教学中的两个常见问题

本文对“示波器的使用”实验教学中关于触发电平的作用、调节它的目的和水平扫描点匀速运动的问题进行了分析和论证。     

动态Dilaton-Maxwell黑洞的广义Stefan-Boltzmann定律

利用动态Dilaton-Maxwell黑洞视界面附近的熵密度,导出黑洞的瞬时辐射流量,得到了任一时刻黑洞沿某一方向的瞬时辐射流量总是正比于在该方向上黑洞事件视界温度的四次方的结论. 导出的广义Stefan-Boltzmann系数不再是一个恒量,而是一个与黑洞视界面附近的时空度规、黑洞视界的变化率及黑洞的吸收与辐射系数有关的动比例系数.揭示了黑洞周围的引力场与其热辐射之间存在着必然的内在联系. 关键词： 熵密度 薄膜模型 瞬时辐射流量 广义Stefan-Boltzmann系数     

Barriola-Vilenkin黑洞Dirac场的广义Stefan-Boltzmann定律

利用薄膜模型研究Barriola-Vilenkin黑洞的热辐射,得到了黑洞的热辐射满足广义Stefan-Boltzmann定律的结论,导出的广义Stefan-Boltzmann系数不再是一个恒量,当截断距离以及薄膜厚度取定后,它是一个与黑洞视界附近的时空度规以及辐射粒子的径向平均泻流速率有关的比例系数.得到的Barriola-Vilenkin黑洞视界附近Dirac场的辐射能通量与薄层膜内辐射粒子的径向平均泻流速率成正比,与黑洞的质量平方成反比。     

广义色散Camassa-Holm模型的奇异孤子

引进一类广义色散Camassa-Holm模型，对其做奇异性分析.通过改进的WTC-Kruskal算法，证明该模型在Painlevé意义下可积，得到了它的一组Painlevé-Bcklund系统和Bcklund变换.应用Maple进行代数运算，得到了丰富的规则(regular)孤子和一类奇异(singular)孤子，扭结(kink)孤子,紧孤子(compacton)和反紧孤子(anti-compacton).特别地，推导出一类在扭结孤子的中间区域包含有一列周期尖点(cuspon)波的奇异结构.在这些规则的孤子系统的基础上，对可积广义系统应用Bcklund变换，得到三类奇异孤子，分别是具有驼峰结构的周期爆破波，具有爆破波结构的扭结孤子和紧孤子. 关键词： 广义Camassa-Holm 模型 周期尖点波 紧孤子 周期爆破波     

Decoherence in generalized measurement and the quantum Zeno paradox

In the development of quantum mechanics, the evolution of a quantum system was a controversial item. The duality of unitary evolution and state reduction as proposed by John von Neumann was widely felt unsatisfactory. Among the various attempts to reconcile the two incompatible modes of dynamics, the model of decoherence has turned out rather convincing.     

量子Zeno效应对原子布居翻转的影响

在量子信息的研究中,量子Zeno效应(QZE)的研究对量子信息的处理有重要作用.针对原子—场相互作用系统,在Jaynes Cummings(JC)模型下,研究在不同测量时间间隔中,布居翻转与初态存活概率的变化趋势.同时得出在时间间隔足够小时,产生QZE,进而得出QZE对布居翻转的影响.     

Quantum Zeno and Anti-Zeno Effects in the Dynamics of Non-Degenerate Hyper-Raman Processes Coupled to Two Linear Waveguides

The effect of the presence of two probe waveguides on the dynamics of hyper-Raman processes is studied in terms of quantum Zeno and anti-Zeno effects. Specifically, the enhancement (diminution) of the evolution of the hyper-Raman processes due to interaction with the probe waveguides via evanescent waves is viewed as quantum Zeno (anti-Zeno) effect. This study considers the two probe waveguides interacting with only one of the optical modes at a time. For instance, as a specific scenario, it is considered that the two non-degenerate pump modes interact with each probe waveguide linearly, while Stokes and anti-Stokes modes do not interact with the probes. Similarly, in another scenario, it is assumed both the probe waveguides interact with Stokes (anti-Stokes) mode simultaneously. The present results show that quantum Zeno (anti-Zeno) effect is associated with phase-matching (mismatching). However, it do not find any relation between the presence of the quantum Zeno effect and antibunching in the bosonic modes present in the hyper-Raman processes.     

Tunneling in polymer quantization and the Quantum Zeno Effect

As an application of the polymer quantization scheme, in this work we investigate the one-dimensional quantum mechanical tunneling phenomenon from the perspective of polymer representation of a non-relativistic point particle and derive the transmission and reflection coefficients. Since any tunneling phenomenon inevitably evokes a tunneling time, we attempt an analytical calculation of tunneling times by defining an operator well suited in discrete spatial geometry. The results that we come up with hint at appearance of the Quantum Zeno Effect in polymer framework.     

Observing quantum trajectories: From Mott’s problem to quantum Zeno effect and back

The experimental results of Kocsis et al., Mahler et al. and the proposed experiments of Morley et al. show that it is possible to construct “trajectories” in interference regions in a two-slit interferometer. These results call for a theoretical re-appraisal of the notion of a “quantum trajectory” first introduced by Dirac and in the present paper we re-examine this notion from the Bohm perspective based on Hamiltonian flows. In particular, we examine the short-time propagator and the role that the quantum potential plays in determining the form of these trajectories. These trajectories differ from those produced in a typical particle tracker and the key to this difference lies in the active suppression of the quantum potential necessary to produce Mott-type trajectories. We show, using a rigorous mathematical argument, how the active suppression of this potential arises. Finally we discuss in detail how this suppression also accounts for the quantum Zeno effect.     

A Krein quantization approach to Klein paradox

In this paper we first introduce the famous Klein tization approach and taking the negative modes into account densities could be achieved without confronting any paradox. paradox. Afterwards by proposing the Krein quan- , we will show that the expected and exact current     

The transition from quantum Zeno to anti-Zeno effects for a qubit in a cavity by varying the cavity frequency

We propose a strategy to demonstrate the transition from the quantum Zeno effect (QZE) to the anti-Zeno effect (AZE) using a superconducting qubit coupled to a transmission line cavity, by varying the central frequency of the cavity mode. Our results are obtained without the rotating wave approximation (RWA), and the initial state (a dressed state) is easy to prepare. Moreover, we find that in the presence of both qubit?s intrinsic bath and the cavity bath, the emergence of the QZE and the AZE behaviors relies not only on the match between the qubit energy-level-spacing and the central frequency of the cavity mode, but also on the coupling strength between the qubit and the cavity mode.     

A new explanation of the extinction paradox

This work presents a new explanation for the extinction paradox and shows that the canonical explanations are incorrect. This paradox refers to the large size limit of a particle's extinction cross section. It is called a paradox because the geometrical optics approximation, which should be valid in this limit, predicts a cross section that is half of the true value. The new explanation is achieved by formulating the scattered wave in terms of an integral over the particle's surface where the seemingly unrelated Ewald-Oseen theorem appears in the formulation. By expressing the cross section in terms of this surface integral, the Ewald-Oseen theorem is analytically connected to the cross section. Several illustrations are used to reveal the significance of this connection: The paradox is seen to be a consequence of the requirement that the incident wave be canceled within the particle by secondary radiation from its own internal field. Following this, the canonical explanations are examined to reveal serious problems. In the process, the same asymptotic extinction behavior is shown to occur for small highly refractive dielectric particles, and thus is not just a large particle size or small wavelength effect as is often stated. The traditional explanations cannot account for this behavior while the new one actually predicts it. All in all, this work constitutes a fundamental reworking of 60 years of accepted understanding for the cause of the asymptotic behavior of the extinction cross section.     

New loophole for the Einstein-Podolsky-Rosen paradox

Using the new concept of "stochastic gauge system", we describe a novel loophole to circumvent the Einstein-Podolsky-Rosen (EPR) paradox. We derive a "realistic" (i.e., classical) model, free from any paradox, which exactly emulates the spin EPR experiment. We conclude that Bell's inequalities are violated in classical physics as well, or, conversely that quantum mechanical theory is logically consistent with relativity.