物理与天文2016arxiv.org
没有粒子,只有场
There are no particles, there are only fields (2012)
进阶 · 约 90 分钟读完前置知识:量子力学基础、量子场论基础、狭义相对论
导读
这篇 2012 年的 arXiv 论文主张量子场论的正确图景是:基本实在只有场,所谓'粒子'只是场的局域激发(波包),并非独立存在的实体。作者从量子场论出发论证粒子概念只是近似描述,并以此反驳'量子神秘主义'式的解读。
HN 关注点:是因为'没有粒子只有场'这一量子场论视角颠覆了大众对量子的直觉理解,讨论集中在如何用场的图像理解希格斯机制、双缝实验等。
HN 评论精选
这几条评论里:支持 2 质疑 1 补充 1
支持用'场及其激发'的图像终于理解了希格斯机制和玻色子的本质
几周前我才真正想通这一点,它让我理解了希格斯场和希格斯玻色子。希格斯场无处不在,就像电子场和电磁场一样(据我理解,每种基本粒子都有自己的场)。当某个场的激发(如电子)与希格斯场相互作用时,会体验到一种'拖拽',这种相互作用赋予它们质量。那希格斯玻色子呢?当你产生足够能量(比如高速对撞两个质子),部分能量进入希格斯场,产生一个场的激发,我们探测到它就是希格斯玻色子。它不稳定,很快把能量释放到其他场,产生更多激发,即我们看到的其他粒子。以前我一直困惑:如果希格斯玻色子负责质量,为什么它出现需要这么大能量?用场的图像一想就全通了。
ptrincr查看英文原文
This only clicked for me a few weeks ago, but it finally gave me an understanding of the Higgs field, and the Higgs-boson. So the Higgs field is everywhere, like the electron field and the electromagnetic field (all elementary particles are thought to have their own field, as I understand it). As excitations of one field (electrons etc) interact with the Higgs field, they experiance a kind of drag and this interaction gives them mass. So how about this Higgs-Boson then? Well if you produce enough energy, like smashing two protons together at huge speeds, this energy is released and some of it ends up in the higgs field, producing an excitation of the field, which we detect as the Higgs Boson. It's unstable and quickly releases it's energy which dissipates into other fields, producing more excitations which we see as more particles. Before I understood this, I was trying to work out how if the Higgs-Boson was responsible for mass, why it needed so much energy for it to appear. All makes sense when you think about it as a field.
支持场的图像能消解不确定性原理和双缝悖论,但进教科书还需时日
再过一百年左右,这大概才会进教科书……量子场论很怪异,但经典世界里比'粒子'更有说服力的类比多得多(费曼偏爱粒子图像,但我想他知道这种表示的问题)。当你用场和波包来思考时,不确定性原理被消解了,双缝实验也不再是悖论——这可不是小成就。
atemerev查看英文原文
And in another 100 years or so, this will finally make it to textbooks... Quantum field theory is weird, but there are much more compelling analogies in classical world than particles. (Feynman was a fan of particles, but I presume he was aware of the problems with this representation). When you speak of fields and wave packets, you eliminate the uncertainty principle, and double-slit experiment is no longer a paradox — no small feat to achieve.
补充推荐 Sean Carroll 关于粒子与场的科普演讲作为补充资料
Sean M. Carroll 谈量子场论时总会提到这个事实,讲得非常精彩,比如 2013 年这场'粒子、场与物理学的未来'(附 YouTube 链接)。
okket查看英文原文
Sean M. Carrol always mentions this fact when he talks about QFT, which can be very entertaining like this one from 2013 "Particles, Fields and The Future of Physics" https://www.youtube.com/watch?v=gEKSpZPByD0 (Audio starts at 19 sec, Lecture starts at 2:00)
质疑质疑:'只有场'的图像反而给量子神秘主义留了更多空间,而非更少
有意思的是论文开头在批判'量子神秘主义'。但在我看来,它的论证反而让量子神秘主义更容易被相信:粒子诉诸我们牛顿式的'台球'直觉,粒子是定域性的化身,粒子宇宙似乎应该是决定论的。而如果粒子只是附带现象,一切都是无限延展的场、只以一定概率相互作用,直觉上意识似乎有更多空间以非定域方式影响这些场。不是吗?我只是在唱反调 :-)
ScottBurson查看英文原文
Interesting that the paper starts by attacking "quantum mysticism". Seems to me that the argument it's making renders quantum mysticism easier to believe rather than harder. The concept of particles, after all, appeals to our Newtonian "billiard ball" intuitions; particles are the essence of locality, and our intuitions suggest that a particle universe should be deterministic. On the other hand, if particles are epiphenomenal, and everything is really infinite fields which only have a certain probability of interacting in certain ways, it seems like, intuitively, there's a lot more room for consciousness to influence those fields in a nonlocal manner. No? Just playing devil's advocate here :-)
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