由于最近的工作需要,重新翻看了这部分内容,为了以后便于查阅,贴在此处。

全部内容来自于梁昆淼著的第四版《数学物理方法》,108-122页。

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数学物理方法摘录(梁昆淼著)-7.1-数学物理方程的导出

Why two shadows bend when close together

视频原地址:https://www.youtube.com/watch?v=dXNyF7lv_Wc

This is called the Shadow Blister Effect. Essentially it’s a bit of an illusion caused by two penumbras, or fuzzy regions at the edge of an objects shadow. As they overlap, they seem to bridge because the prenumbras start to mix and create a darker shaded area. The eye doesn’t consider the penumbra to be part of the shadow since its brighter than the shadow, but when they merge they are dark enough to be considered by the eye to be part of the shadow.

这叫做“”。它其实有点像幻象,因为两个黑黑的影子周围其实存在着不太明显的半影,当两个物体靠近时,其半影将融合,加深其颜色,人们看起来就像是原来的影子在互相吸引并融合在一起一样。

Is This What Quantum Mechanics Looks Like?

原地址:https://www.youtube.com/watch?v=WIyTZDHuarQ, 带cc中文字幕。

Silicone oil droplets provide a physical realization of pilot wave theories.

Check out Smarter Every Day: http://bit.ly/VeSmarter

Support Veritasium on Patreon: http://bit.ly/VePatreon

If you want to try this experiment, instructions are here: link.springer.com/article/10.1007/s12650-016-0383-5

The standard theory of quantum mechanics leaves a bit to be desired. As Richard Feynman put it, “I think I can safely say that no one understands quantum mechanics.” This is because observations of experiments have led us to a theory that contradicts common sense. The wave function contains all the information that is knowable about a particle, yet it can only be used to calculate probabilities of where a particle will likely turn up. It can’t give us an actual account of where the particle went or where it will be at some later time.

Some have suggested that this theory is incomplete. Maybe something is going on beneath the radar of standard quantum theory and somehow producing the appearance of randomness and uncertainty without actually being random or uncertain. Theories of this sort are called hidden variable theories because they propose entities that aren’t observable. One such theory is pilot wave theory, first proposed by de Broglie, but later developed by Bohm. The idea here is that a particle oscillates, creating a wave. It then interacts with the wave and this complex interaction determines its motion.

Experiments using silicone oil droplets on a vibrating bath provide a remarkable physical realization of pilot wave theories. They give us a physical picture of what the quantum world might look like if this is what’s going on – and this theory is still deterministic. The particle is never in two places at once and there is no randomness.

Edited by Robert Dahlem; Sound design by A Shell in the Pit.

在微信的理论物理群里看到有老师分享了这样一篇文章:Wolfram 发现的新物理

大概意思是说,Mathematica软件的老板斯蒂芬·沃尔夫勒姆(Stephen Wolfram)自己做的这项研究,从题目上看是典型的民科研究,但实际上并没那么简单。因为Stephen Wolfram本身就是物理学博士出身,创办了著名的计算软件Mathematica。虽然不再在主流渠道从事物理研究,但他并未放弃物理。最近,Stephen Wolfram在自己的博客上刊出了两篇博文,介绍了自己的工作。以下就是博文内容:

How We Got Here: The Backstory of the Wolfram Physics Project  (This essay is also in:  SoundCloud »

Finally We May Have a Path to the Fundamental Theory of Physics… and It’s Beautiful

我打开翻了一下,发现篇幅很长,因此没仔细看。但从知乎文章的介绍和博文的配图可以看到,里面有不少有趣的思想。

本文写在这里,一是介绍,二是做个记录,方便我之后的浏览。

他的相关网站:

The Wolfram Physics Project —— A Project to Find the Fundamental Theory of  Physics.  https://www.wolframphysics.org/

他于2002年写的书《A new kind of Science》(一种新科学)详细阐述了自己的研究。在线阅读链接:https://www.wolframscience.com/nks/

不过,他的研究似乎受到很多人的批评。知乎上有一个页面专门讨论这个话题:如何看待Stephen Wolfram声称万物理论已被发现? – 知乎 https://www.zhihu.com/question/387862824

Wolfram声称这本书时科学史上最重要的一部著作,而他所做的一切都不亚于牛顿的贡献。这当然引来不少非议,很多学者说他是个疯子,自大狂。也有不少人,无论从事理工科还是社会学科,都从这本书中获得不少灵感和启发。

2010年,Wolfram还在TED上对自己的理论进行了介绍:【TED 演讲】Stephen Wolfram:计算万物的理论


延伸阅读:

Stephen Wolfram:《一种新科学》15周年回顾

知乎上一个非常详尽的回答:如何看待Stephen Wolfram声称万物理论已被发现? – La Vie的回答 – 知乎 https://www.zhihu.com/question/387862824/answer/1157830985

What are the Deep Laws of Nature?

What’s fundamental? What’s bedrock reality? What are the deep regularities, things that work the same—always, everywhere—across the universe? Are these regularities “laws”?  Where do they come from?

视频简介:(原地址:https://www.youtube.com/watch?v=HsMUbZDNlik

话题大致有以下分类:

受采访的对象包括但不限于威腾、温伯格、索恩等物理大师。

以上的这些主题都归属于来自于 Deep Laws of Nature,而 Deep Laws of Nature 归属于 Closer to Truth.

Closer to Truth 包括以下主题:COSMOSCONSCIOUSNESSMEANING

都值得好好看看。

它的所有视频都做了播放列表,在它的YouTube频道里。观看地址为:https://www.youtube.com/user/CloserToTruth1

 

以前在几个杂志上投过稿,国内的几个都升级为了三区。好事情。

查询网站:http://www.letpub.com.cn/index.php?page=journalapp

以下三个杂志升级:

COMMUNICATIONS IN THEORETICAL PHYSICS 中国,2019年影响因子1.24,三区(升级了)

CHINESE PHYSICS LETTERS 中国,2019年影响因子0.93,三区(升级了)

Chinese Physics B 中国,2019年影响因子1.27,三区(升级了)

真是好消息。

这个杂志没变:

INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS 美国, 2019年影响因子1.02, 四区

另外,有一个杂志降级了:

INTERNATIONAL JOURNAL OF MODERN PHYSICS A 新加坡,2019年影响因子1.16 四区 (降级了)

 

 

What is RAINBOW GRAVITY THEORY? What does RAINBOW GRAVITY THEORY mean?

视频地址:https://www.youtube.com/watch?v=Dovnk2lJpnk

简介:

Rainbow gravity (or “gravity’s rainbow”) is a theory that different wavelengths of light experience different gravity levels and are separated in the same way that a prism splits white light into the rainbow. This phenomenon would be imperceptible in areas of relatively low gravity, such as Earth, but would be significant in areas of extremely high gravity, such as a black hole. As such the theory claims to disprove that the universe has a beginning or Big Bang, as the big bang theory calls for all wavelengths of light to be impacted by gravity to the same extent. The theory was first proposed in 2003 by physicists Lee Smolin and Joao Magueijo, and claims to bridge the gap between general relativity and quantum mechanics. Scientists are currently attempting to detect rainbow gravity using the Large Hadron Collider.

彩虹引力(或“引力的彩虹”)是一种理论,即不同波长的光会经历不同的引力水平,并且以与棱镜将白光分成彩虹的相同方式分开。 这种现象在重力较低的区域(例如地球)是无法察觉的,但在重力非常高的区域(例如黑洞)则非常明显。 因此,该理论声称不能证明宇宙有一个开始或大爆炸,因为大爆炸理论要求所有波长的光都受到重力的影响。 该理论最早由物理学家李·斯莫林(Lee Smolin)和乔奥·马格乔(Joao Magueijo)于2003年提出,声称弥合了广义相对论与量子力学之间的鸿沟。 科学家目前正在尝试使用大型强子对撞机检测彩虹引力。

Rainbow gravity theory’s origin is largely the product of the disparity between general relativity and quantum mechanics. More specifically, “locality,” or the concept of cause and effect that drives the principles of general relativity, is mathematically irreconcilable with quantum mechanics. This issue is due to incompatible functions between the two fields; in particular, the fields apply radically different mathematical approaches in describing the concept of curvature in four-dimensional space-time. Historically, this mathematical split begins with the disparity between Einstein’s theories of relativity, which saw physics through the lens of causality, and classical physics, which interpreted the structure of space-time to be random and inherent.

彩虹引力理论的起源很大程度上是广义相对论与量子力学之间差距的产物。 更具体地说,“局部性”或驱动广义相对论原理的因果关系在数学上与量子力学不相容。 此问题是由于两个字段之间的功能不兼容所致。 特别是,这些领域在描述四维时空曲率的概念时采用了截然不同的数学方法。 从历史上看,这种数学上的分歧始于爱因斯坦的相对论和经典物理学之间的差异,后者是通过因果关系的视角看待物理学,而经典物理学则将时空的结构解释为是随机的和固有的。

The prevailing notion about cosmic change is that the universe is expanding at a constantly accelerating rate; moreover, it is understood that as one traces the universe’s history backwards one finds that it was, at one point, far denser. If true, the Rainbow gravity theory prohibits a singularity such as that which is postulated in the Big Bang. This indicates that, when viewed in reverse, the universe slowly approaches a point of terminal density without ever reaching it, implying that the universe does not possess a point of origin.

关于宇宙变化的普遍观念是宇宙以不断加速的速度膨胀。 此外,可以理解的是,当人们追溯宇宙的历史时,就会发现它在某一点上更加密集。 如果为真,则Rainbow引力理论禁止像Big Bang中所假定的那样的奇异性。 这表明,从相反方向看,宇宙缓慢地到达了终极密度点而从未到达终极点,这表明宇宙不具有原点。

There are stringent constraints on energy-dependent speed-of-light scenarios. Based on these, Sabine Hossenfelder has strongly criticised the rainbow gravity concept, stating that “It is neither a theory nor a model, it is just an idea that, despite more than a decade of work, never developed into a proper model. Rainbow gravity has not been shown to be compatible with the standard model. There is no known quantization of this approach and one cannot describe interactions in this framework at all. Moreover, it is known to lead to non-localities which are ruled out already. For what I am concerned, no papers should get published on the topic until these issues have been resolved.”

在能量依赖型光速场景中有严格的限制。 基于这些,萨宾·霍森菲尔德(Sabine Hossenfelder)强烈批评了彩虹引力的概念,他说:“它既不是理论也不是模型,它只是一个想法,尽管经过十多年的努力,但从未发展成为合适的模型。 尚未显示出与标准模型兼容的信息;没有已知的量化方法,并且根本无法描述此框架中的相互作用;而且,已知会导致已经排除的非局部性。 我担心,在解决这些问题之前,不应发表任何有关该主题的论文。”


The Rainbow Gravity Theory! (Theory Thursday Ep.1)