物理是否实验科学的辩论还在继续。任何“哲学”性问题最终可以归结为定义的问题。“实验科学”的定义是什么?在没有准确定义这个名词之前,继续争论没有意义。我们不如从物理的发展史得到一些具体的启示。如果认真回顾下物理学从亚里士多德到牛顿的发展历史,我们会惊人的发现,亚里士多德的是基于经验的物理,而牛顿是理想化的抽象。亚里士多德的物理统治西方一千多年,正是经验的局限,而牛顿及之后的物理是经验的理性突破, 是特殊性的数学化扬弃。 先看一个客观的物理现象:运动物体如果没有推动最终会停下来。这个谁都可以做实验,你可以在冰上试,在气垫上试,在不同时间、地点实验,结果都相同,运动物体最终会停下来。有人可能说,地面上的物体确实会停下来,但是日月星辰呢?对此的辩解是,那正说明日月星辰有某种作用在推动,你也没办法把月球拿到实验室测试。。。如此等等。如果我们把物体最终会停下作为基本物理规律,这应该算是实验科学的结果吧?且让我把这个称为“最终静止律”,它具有可证伪性,完全符合实证科学的定义。 亚里士多德在其《物理》一书的第四卷第8章论述到:真空在各个方向、各地点都没有区别,因此【 没人可以说为什么一个物体被推动之后就应该停下;因为为什么它应该在这停下而不是在那呢?这样一个物体或者将处于静止或者将永远运动下去,除非一个更强的物体阻挡它 】(“no one could say why a thing once set in motion should stop anywhere; for why should it stop here rather than here? So that a thing will either be at rest or must be moved ad infinitum, unless something more powerful get in its way.” (英译本)) 用今天的话说,亚里士多德从真空的平移与旋转不变性得出,真空中的物体将保持其运动状态。读者看到这,可能要惊呼,亚里士多德早就发现了牛顿第一定律!但是不幸的是,他这是在用反证法证明真空不存在。亚里士多德的逻辑是:如果存在真正的真空,那么物体将保持其运动状态,这就违背了“最终静止律”,可见真空不存在。 亚里士多德的自由落体理论是相当高明的。在其书中的同一章节,他写道 如果形状大小相同 ,那么物体的终极速度正比与重量,反比于其所在运动介质的密度,v = W/d 。根据今天的流体力学,这个结果至少在低速情况是正确的。亚里士多德的理论因此是可以实验验证的。然后亚里士多德举了空气与水作为例子。接下来,亚里士多德论证到,如果存在真空,那么自由落体的终极速度是无穷大,这很荒谬,可见真空不存在。 "Natura abhorret vacuum." (自然界厌恶真空)。今天的标准模型里,真空中必须有不为零的希格斯场。我们不能轻易嘲笑两千多年前的希腊先哲。 亚里士多德的物理可以说是基于实验现象的、逻辑相当严密的物理。而牛顿的物理可以说是从实验升华、理想化之后的物理。这种从纷繁芜杂的现象中排除其他因素,构想出理想模型的能力就是物理直觉。一个力学问题,物理不好的往往会立刻联想起摩擦力、空气阻力、物体形状等等等等因素,把问题弄得很复杂,然后宣布无解;而物理好的往往能直接把问题分解、简化,各种因素作为修正。牛顿力学的第一定律正是被亚里士多德否定了的理想情况。基于这一点,才有接下来的第二定律,那就是力的作用不是维持运动,而是改变运动。在亚里士多德那里, F = v * R (v 为速度,R为阻碍),这是基于实验相当不错的学说。但一旦走出经验的束缚,意识到理想情况下无外力物体将维持运动状态,有外力的作用才会改变运动,离 F = ma 也就不远了。 亚里士多德物理中把星体与地面物体区别对待,认为它们做永恒的圆周运动。从直观上看,他是有道理的,也可以说是基于实验观察。我们完全可以宣布亚里士多德是很好的实验与理论物理学家,他不仅有实验,也有理论。 而牛顿的思想突破在于认为巨大的星体跟地球上一个苹果一样遵循同样的物理规律。牛顿理论从直观上看与观测相差甚远 --- 月球在绕地球转,苹果直线下落。 在亚里士多德看来星体的圆周运动是一种恒定的运动,而牛顿时代人们已经明白,圆周运动相当于直线运动不但地碰撞转向,是加速运动。 牛顿物理的胜利在于其理论的数学计算最终与实验结果高精度吻合。 因此,物理从亚里士多德到牛顿的发展,不是实验与理论的差异,关键在于是否数学化。亚里士多德的物理虽然是根据实验观察,但没有数学化,即使能够勉强维持逻辑的自洽,也并不具备可精确验证性,也就跟阴阳五行之类学说没有太大的区别了。而牛顿力学则是精确数学化的,也就是实打实的硬道理。牛顿并不试图解释为什么有超距的引力作用,而是说平方反比加 F=ma,算吧。算出来总能对上,理论就是成功了。算出来不对,理论就自然需要纠正。后来人们发现水星进动速度用牛顿引力算出来与观测结果相差百分之0.8% 就开始思考牛顿理论是不是可以修正下。最初人们的想法是借鉴电磁理论,把物质流与电流对比,产生所谓引力磁场,好像也能行。但不久爱因斯坦从自由落体的思想实验出发建立了协变性的引力几何理论,又引发了一场物理的革命。到今天, 物理已经被归结于两个基本原理:作用量原理与规范不变。 而物理的每一次革命,都是特殊性的数学化废除。牛顿废除了天体的特殊性,爱因斯坦废除了惯性系的特殊性,量子力学废除了直线运动的特殊性。到目前为止,物理的这个发展思路非常成功。
钱换不来爱情,钱换不来。。。(the list continues ). 廖凯原捐一亿美金,也得不到去北大物理系讲 “凯原量子信息力学KQID” 的机会,而只能去北大法学院讲。这说明什么? 这再次说明钱不是万能的。钱换不来科学地位。 廖凯原 就花10亿美金,其“凯原量子信息力学KQID”也得不到一次物理学权威刊物正规的引用。 廖凯原就算可怜鸡师傅,花一亿美金给鸡打脑白金,鸡师傅也还是不懂初中物理,也还是只能进野鸡大学,不仅不会解决走路上楼梯的初中物理问题,而且惨到连正确答案摆在面前也看不出这是正确答案。 Oh, let's not forget what I wrote in Court: 【Yang had college education from Nanjing Chemical Engineering College, Nanjing, China (Chinese: 南京化工学院).He studied as a graduate student in the 1990s at the University of Paderborn in Germany, where he graduated in 1999. No scholarly papers can be found to be authored by Defendant Yang in leading western research journals】 从数百次引用中挑几个,再次让 Red-eye-chicken-master 看看什么叫引用: Hawking radiation in sonic black holes S. Giovanazzi∗ The long-range part of the Coulomb interaction could substantially renormalize the Hawking temperature in long wires in a way similar to how it does for the scattering from an impurity . Conductance of Interacting Quasi-One-Dimensional Electron Gas with a Scatterer Authors: A. V. Borin, K. E. Nagaev .... The summation of most divergent contributions may be performed using the renormalization procedure suggested by Yue et al.14 . Transport properties of a two-lead Luttinger liquid junction out of equilibrium: fermionic representation Authors: D.N. Aristov, P. Wolfle The transport through Luttinger liquid junctions at not too strong interaction has also been calculated using the Functional Renormalization Group method as reviewed in14 ...In this paper we extend the approach of Yue et al Electron-electron interaction effects on transport through mesoscopic superconducting hybrid junctions Authors: Arijit Saha Weak interaction renormalization group approach In this sub section we introduce the weak interaction renormalization group (WIRG) method which was first developed by Yue et al. Functional renormalization group approach to correlated fermion systems Authors: Walter Metzner, Manfred Salmhofer, Carsten Honerkamp, Volker Meden, Kurt Schoenhammer ... The idea of an oscillatory decaying potential is similarly inherent to a poor man’s fermionic RG approach (Yue et al., 1994). Conductance through a potential barrier embedded in a Luttinger liquid: nonuniversal scaling at strong coupling Authors: D.N. Aristov, P. Woelfle The fermionic representation offers the possibility to connect the fermionic degrees of freedom in the (non-interacting) leads smoothly with the degrees of freedom in the interacting system. In other words, it allows to use the scattering states of the system in the non-interacting limit as a basis of description. On the simplest level, in lowest order in the interaction, this program has been carried out in a seminal paper by Yue , Matveev and Glazman. Spintronics with NSN Junction of one-dimensional quantum wires : A study of Pure Spin Current and Magnetoresistance Authors: Sourin Das, Sumathi Rao, Arijit Saha We see that there is a logarithmic singularity at the k → 0 limit which implies that the lowest order perturbation theory is not enough to calculate correction to the reflection and AR amplitudes when the momenta of the incident particles are very close to the Fermi wave vector. Following Yue et al. , we sum up these most divergent processes using the ”poor man’s scaling” approach to obtain RG equations for the normal refection amplitude... Functional Renormalization-Group Analysis of Luttinger Liquids with Impurities Authors: Sabine Andergassen For Luttinger liquids with repulsive interactions (Kρ 1) already a single static impurity has a strong effect at low energy scales, even if the impurity potential is relatively weak . Junction of several weakly interacting quantum wires: a renormalization group study Authors: Siddhartha Lal (1), Sumathi Rao (2), Diptiman Sen (1) ((1) IISc, Bangalore, (2) Pennsylvania State University and HRI, Allahabad) Yue et al use this idea to derive the RG equations for an arbitrary S-matrix located at the junction of two semi-infinite wires... Let us briefly present the method of Yue et al. .... Yue et al then derive the RG equations for the S-matrix which is now considered to be a function of a distance scale L; they show that −ln(kd) in Eqs. (17-18) can effectively be replaced by dl, where l = ln(L/d). ..Yue et al show that the backscattering interaction governed by g1 leads to a logarithmic renormalization of the interaction parameters g1 and g2 ; we will ignore that effect here since it plays no role to first order in the gi . I-V characteristics and differential conductance fluctuations of Au nanowires Authors: H. Mehrez, Alex Wlasenko, Brian Larade, Jeremy Taylor, Peter Grutter, Hong Guo In the rest of this section, we follow the interesting idea of the charging effect and analyze it in more detail to understand if this effect, which leads to channel closing53,54 can give rise to nonlinear I-V curves of atomic devices. To start, we follow the work of Yue et. al.71 by assuming a strong interaction and write the renormalized transmission coefficient...