物理学最大谜题：反物质、暗能量与万有理论 — Don Lincoln | Lex Fridman Podcast #497

The following is a conversation with Don Lincoln, a particle physicist at Firmeny Lab, who has spent decades working at the frontier of high energy physics. 以下是与唐·林肯的对话，他是费米实验室的粒子物理学家，数十年来一直活跃在高能物理学的前沿。 This was a mind-blowing and inspiring conversation. 这是一次令人大开眼界、深受启迪的对话。 Don turned out to be one of my favorite people to talk to about physics. 唐最终成了我最喜欢与之探讨物理学的人之一。 truly a unique mind with that Richard Fineman ability of taking very complicated ideas and explaining them simply without losing any of the essential brilliant insights at the core of those ideas. 他拥有真正独特的思维，就像理查德·费曼那样，能够把极其复杂的想法深入浅出地讲清楚，同时又不失其核心的精彩洞见。 This is the Lex Freedman podcast. 这里是莱克斯·弗里德曼播客。 To support it, please check out our sponsors in the description where you can also find ways to contact me, ask questions, give feedback, and so on. 如果想支持我们，请查看简介中的赞助商信息，那里还有联系我们的方式。 And now dear friends, here's Don Lincoln. 亲爱的朋友们，现在请听唐·林肯。 In describing the search for theory of everything in physics, you describe the history of physics can be told effectively as a kind of history of unifications. 在描述物理学万物理论的探索过程时，你将物理学的历史比作一场不断统一的旅程。 There's this centuries long quest to show that these distinct phenomena are actually linked by some unified underlying principles. 几个世纪以来，人们孜孜以求，试图证明那些看似截然不同的现象，其实被某种深层规律贯穿联系。 uh even starting with Newton that you can think of the effort of physics as one as trying to unify the laws of nature. 甚至从牛顿开始，你就可以把物理学的努力理解为一种统一各种力的尝试。 So I was wondering if we could talk through the history of unification that lens of physics. 所以我想我们可以聊聊统一这条主线下的物理学史。 There are of course lots of different ways to do physics, but the the way that I would say that particle physicists, cosmologists do is they are trying to to really find basically the underlying principles that govern the laws of of nature. 当然，做物理学有很多种方式，但我想说的是，在这个领域有一个特别突出的视角，那就是统一。 If we go back say to the I don't know 1650s or so, uh you're the most brilliant person around and you've noticed two things. 如果我们回到大约1650年代，你是那个时代最聪明的人，你会发现什么？ One you've noticed is that when you trip, you fall. 你注意到的一件事是：绊倒了，人就会摔下去。 That is the nature of gravity that that we all experience daytoday. 这就是我们日常都能体验到的重力本质。 But then there's sort of astronomy where you look out at the heavens and you see the stars march across the sky. 但还有一种天文学，抬头仰望天空，看到星辰在天际运行。 You see the planets move through the stars and there that seems to have absolutely nothing to do with what happens when you drop your sandwich and and the dog grabs it from you. 你看到行星在星空中穿行，那似乎与绊倒摔跤这回事毫无关联。 So yeah, 确实， the brilliant thing was when Newton looked at that and he thought about maybe the moon is falling but it's missing the earth. 牛顿的天才之处在于，他看到这一切后，想到了也许月球也在下落，只是在做圆周运动。 So what we had is that in maybe 1650 you had what we might call the laws of celestial gravity, the gravity that governs the heavens and terrestrial gravity, the gravity that is here on Earth. 所以大约1650年，我们有了所谓的天体引力定律和地面引力定律。 Now we don't think of that that way anymore. 现在我们不再这样区分了。 We think of it as just gravity. 我们只把它看作引力。 But at that time that wasn't at all obvious. 但在那个时代，这一点根本不是显而易见的。 And in fact, if you look in the books, Newton's theory is Newton's law of universal gravity. 事实上，翻开书本，牛顿的理论叫做牛顿万有引力定律。 The universal is there. 万有二字就在那里。 And the reason is is because he realized these two things that seem to have nothing to do with one another were indeed one and the same. 原因就在于他意识到，这两件看似毫不相干的事情，其实是同一件事。 I mean, this is absolutely brilliant. 我的意思是，这真的太精彩了。 I mean, Newton is arguably one of the most brilliant humans I of which I'm ever aware. 牛顿可以说是我所知晓的最聪明的人之一。 But at any rate, it is the first sort of easily to describe unification of physics that you can state in a way that sort of makes sense to to modern humans. 但无论如何，这是物理学中最容易描述的第一次统一，你可以用一句话来说明它。 I mean, you can go back farther than that where people are talking about chemistry, the nature of atoms. 当然，你可以追溯得更远，人们还在谈论化学、原子的本质等等。 You go back to Democrus who was wrong about very many things, but the idea that there was a smallest particulate form of matter is right. 回溯到德谟克利特，他在很多事上都是错的，但物质存在最小粒子单元这一想法是正确的。 So, it's kind of funny. 所以，其实挺有趣的。 You talk, you read the chemistry books and they say that the idea of atoms goes back to Democrus and you know he his idea was that like um there was a smallest atom of oil which was smooth and it was smooth of course because well oil is smooth. 你读化学书，书里说原子的概念可以追溯到德谟克利特。 There was a smallest atom of vinegar because vinegar is tart and it pricks your tongue so therefore atoms were little sharp pointy things. 醋有最小的原子，因为醋是酸的，会刺激你的舌头，所以那个原子是带尖刺的。 Um and so he was wrong about a lot but he was right about the idea that there was a small particle and and we now know a very we have a very different concept than he did. 他在很多事上都错了，但他关于存在最小粒子单元的想法是对的。 So you can go back farther than that but getting to unification there are more examples. 所以你可以追溯得更远，但说到统一，还有更多例子。 For instance if you go back to say 1830 or so scientists were trying to understand electricity for instance and there was a lot going on. 比如回到大约1830年，科学家们正在试图理解电和磁。 people really understood things. 人们真的搞懂了一些东西。 But at the time you would have two phenomena that are familiar to us now. 但在那个时候，有两种我们现在都熟悉的现象。 One is a magnet which you know at the time mostly magnets were were simply little pieces of iron that had been magnetized and they could stick to steel. 一种是磁铁，在当时主要就是一些小铁块，被叫做天然磁石。 And then you had electricity which was at the time they were generating little sparks that they could play and and have fun with or more broadly a uh a lightning bolt blazing across the sky. 另一种是电，那时候他们产生的不过是一些小火花，有时也叫摩擦电。 And so when you think about this, that lightning bolt and that little magnet seemed to be really unrelated. 所以你想想，那道闪电和那块小磁铁，看起来完全没有任何关系。 Mhm. 嗯。 Um but over the 1800s, a number of scientists were exploring little aspects of it. 但在整个19世纪，许多科学家一点一点地探索着它的各个方面。 What happens when you run electricity through a wire? 把电通过导线会发生什么？ It seems to make a magnetic field. 似乎会产生磁场。 You know, they was a whole bunch of experiments and there were a lot of names. 做了很多实验，涉及很多名字。 But in about the 1860s or so, James Clark Maxwell took all of those ideas that had been percolating around for the previous 50 years and wrote his laws of electromagnetism. 但大约在1860年代，詹姆斯·克拉克·麦克斯韦把所有那些东西拼凑在一起，整理成一套方程组。 And they're really fascinating. 而且这些方程组真的很迷人。 If you look at the laws of electromagnetism, they are they're differential equations or integral equations. 如果你看那些电磁学定律，它们是微分方程，或者用积分形式表示。 But basically what they say is on one side you have a bunch of terms that have electricity in them and then you have equals on the other side a magnetism thing. 但基本上，方程的一边是与电相关的项，另一边是与磁相关的项。 So forgetting all of the mathematical symbols you have electricity side equals a magnetism side. 撇开所有数学符号不谈，就是电的这边等于磁的那边。 Electricity equals magnetism. 电等于磁。 And that is a staggering concept. 这是一个令人震撼的概念。 The fact that these two things a lightning bolt and the magnet that holds your kids art to the refrigerator are one and the same. 这两样东西，闪电，和把你家孩子画贴在冰箱上的磁铁，本质上竟是同一种力。 And this was another case where electricity and magnetism became unified into electromagnetism. 这又是一次统一，电和磁统一成了电磁力。 So now we have two examples. 现在我们有了两个例子。 One, gravity being unified, terrestrial and celestial gravity, and then electricity and magnetism. 一个是引力的统一，把地面引力和天体引力合二为一；另一个是电和磁统一成电磁力。 So I I'll tell you about some more in a moment. 稍后我再给你讲更多。 But one thing that's kind of important because the goal is of course to to unify everything that if if I could do what I want to do, I would have some unified theory that would explain all the behavior of all energy, matter, space and time, which is a grand goal. 但有一件事挺重要，因为目标当然是统一一切。 And and we should say that maybe one of the goals of science more broadly outside of physics even is to construct uh models that can generalize the world. 而且我们应该说，也许更广泛的科学目标之一，不仅仅是物理学，也有类似的统一性。 So if you look at Darwinian evolution that was a very beautiful theory that captures another layer of reality of like how this particular thing that we see here on earth happens right 达尔文进化论就是一个非常美丽的理论，它捕捉到了另一个层面的统一。 so when we talk about theory of everything in physics that's capturing a different layer of abstraction about the functioning of the universe 所以当我们谈论物理学中的万物理论时，那是在捕捉不同层面的统一。 right the whole Darwinian evolution the fact that our genetics has significant overlap with genetics of a banana is is pretty staggering is astonishing that that works. 是的，达尔文进化论，以及我们的基因与其他物种有大量重叠这一事实，真的令人惊叹。 So that is amazing. 这太了不起了。 Um but for at least the class of of scientists that I am what we think of is well sure biology is interesting and all but when you get right down to it it's it's it's caused whatever happens in biology is caused by the movement of molecules. 但至少对于我这类科学家来说，我们思考的是：好，当然生物学是真实的，化学也是真实的，但分子之所以这样运作，是因为原子在相互作用。 And then you say,"Well, that's great and all, but molecules, they do what they do because they're made of atoms." 然后你会说，好吧，这很好，但分子是这样运作的，因为原子的相互作用方式就是如此。 And then the next step is, well, you know, atoms, that's great, but atoms work the way they do because of the nucleus and the electrons. 再往下一步，原子很好，但原子的运作方式取决于原子核和电子的行为。 And then the nucleus is protons and neutrons. 而原子核是由质子和中子组成的。 And so there are those of us, myself included, who want to dig down at to the very very bottom and find out what is the smallest building block of nature from which all of these other far more complex and interesting and abstract things are, but what is at the very very bottom? 所以我们当中有一些人，包括我自己，想一直往下挖，挖到最底层，去理解最基本的规律。 And also that's great, but if you know um what the smallest building blocks are, that doesn't tell you the story. 还有一点很重要，知道最小的构建模块是什么很好，但这还不足够。 That's like having a whole bunch of Legos but not knowing how to put them together. 这就像有一堆乐高积木，却不知道怎么把它们拼在一起。 You also need to know how they interact, how they work. 你还需要知道它们如何相互作用，如何运作。 And so that's what we study forces. 所以这就是我们研究力的原因。 So there are the various subatomic forces of which we're familiar. 所以亚原子层面有各种各样的力，我们对此有所了解。 And um for instance, electricity and magnetism are components of electromagnetism which then governs the behavior of things like this is amazing. 比如，电和磁是电磁力的组成部分，而电磁力由光子传递。 Electric electromagnetism explains of course electricity magnetism but it explains how light works. 电磁力当然解释了电和磁，但它也解释了光是如何传播的。 It explains how much of chemistry works. 它解释了很多化学反应是如何发生的。 So electromagnetism 1860 or 70 uh the wonderful thing about that is if you take Maxwell's equations and you apply a little bit of calculus it's very easy to see that the laws of electricity and the laws of magnetism combined together make what's called a wave equation which that's shows that these electric and magnetic fields oscillate. 电磁力大约在1860至70年代确立，它有一个精妙之处：如果你取麦克斯韦方程组并求解，你会发现场在随时间变化。 they they vary. 它们在变化。 And if you have a something that's varied, that's a wave. 如果有什么东西在变化，那就是一种波。 And the wave then moves. 而这种波会向外传播。 And if you do the math, you find out that the speed at which these waves move is the speed of light. 做一下数学运算，你会发现这些波传播的速度就是光速。 And so people said,"Wow, the speed of light comes out of those equations." 于是人们惊呼：哇，光速从这些方程里直接推导出来了。 And that had to be, I think, very persuasive. 我认为这肯定极具说服力。 And of course, electromagnetism also plays a really significant role in chemistry because after all, atoms are held together by electromagnetic forces. 当然，电磁力在化学中也扮演着非常重要的角色，因为原子的相互作用主要靠电磁力。 There's more to how atoms work. 原子的运作还涉及更多方面。 There is all the quantum mechanic stuff. 还有所有量子力学的东西。 But if you did not have electromagnetism or if electromagnetism was very different, then atoms would be very different. 但如果没有电磁力，或者电磁力非常不同，那么原子就根本不会以同样的方式聚集在一起。 So it plays a very big role in in holding us together. 所以它在将我们凝聚在一起这件事上发挥着非常重要的作用。 So it it's a a staggering advance in science to have a good behavior on that. 所以，在这方面取得进展，是科学上的一大飞跃。 And of course being able to to tame electromagnetism is why people can hear you when you do your podcast because through the miracles of the internet just or just electricity running the computers. 当然，能够驾驭电磁力，才使得人们在数百英里之外也能听到你说话。 I mean, this is a case, if I can get on a small soap box, where people back then said,"Well, why are you messing around with magnets and sparks and who cares?" 我是说，如果我可以稍作感慨：那时候有人说，好吧，研究这些，你能有什么收获？ Well, that very fundamental digging into the laws of nature has spin-offs. 而恰恰是这种对自然规律的深入探索，产生了意想不到的成果。 And it has spin-offs. 而且这种成果是不断涌现的。 One of the big spin-offs is our entire technological society. 其中一个巨大的成果就是我们整个现代科技社会。 without being able to govern electricity, we'd still be farmers and shoemakers in cities, but we certainly would not have everything that we do. 如果无法驾驭电，我们现在还会是城市里的农民和鞋匠。 So, off my soap box, but it's really a lovely thing to show how this this digging into deep fundamental, not understood, mysterious things can 100 or 200 years later transform the world. 所以，感慨结束，但这真的很美好，展示了深入探索基础规律会带来怎样的成果。 And the type of science I do now, people often ask, well, what good is knowing about how the inside of atoms work, how the inside of quarks work. 我现在做的这类科学，人们常常问：知道宇宙中最小粒子的行为，有什么用？ And I don't know the answer to that. 我不知道答案。