# 杨振宁史上最精彩的演讲，没有之一，全程高能，太吸引人了！顶级物理学家的思维，究竟与普通人有多大差距

https://www.youtube.com/watch?v=Z90fkUa7fbw
Translation: zh-CN

[00:00] I was born in Hefei, Anhui Province, in 1922.
  我于1922年出生在安徽省合肥市。

[00:03] I left Hefei when I was six and first lived in Xiamen for a year because my father taught at Xiamen University.
  我六岁时离开合肥，在厦门住了一年，因为我父亲在厦门大学任教。

[00:11] Then, in 1929, when I was seven, my father became a professor at Tsinghua University.
  然后，在1929年，我七岁时，我父亲成为清华大学的教授。

[00:16] So, my father, my mother, and I moved to Tsinghua University.
  所以，我和我的父亲、母亲一起搬到了清华大学。

[00:22] I attended the Chenzhi Primary School there.
  我在那里就读于成志小学。

[00:30] After graduation, I went to a church school in the city, established by the Anglican Church.
  毕业后，我去了城里的一所由圣公会建立的教会学校。

[00:35] At that time, I think two-thirds of Peking's middle schools were church schools, and Chongde Middle School was one of them.
  当时，我认为北京三分之二的中学是教会学校，崇德中学是其中之一。

[00:46] I attended Chongde Middle School for four years, from the first grade of junior high school to the first grade of senior high school.
  我在崇德中学就读了四年，从初中一年级到高中一年级。

[00:53] During those four years, I think the thing that had the greatest impact on me later in life
  在那四年里，我认为对后来我生活影响最大的事情

[01:00] It was its small library.
  它就是它的小图书馆。

[01:02] This small library contained books introducing new scientific developments at the time.
  这个小图书馆里载有介绍当时新科学发展的书籍。

[01:12] One of the books I remember reading was "The Mysterious Universe," translated into Chinese.
  我记得读过的一本书是《神秘的宇宙》，这本书被翻译成了中文。

[01:18] The author was James James, a prominent physicist of the time.
  作者是詹姆斯·詹姆斯，当时一位杰出的物理学家。

[01:23] What did he write about?
  他写了什么？

[01:26] He described three major revolutions in physics in the first 30 years of the 20th century.
  他描述了20世纪前30年物理学的三个重大革命。

[01:32] These three revolutions were the special relativity of 1905.
  这三次革命是1905年的狭义相对论。

[01:35] The general relativity of 1915 and the quantum mechanics of 1925 were two of the most astonishing of these three revolutions.
  1915年的广义相对论和1925年的量子力学是这三次革命中最令人惊讶的两次。

[01:46] Two and a half of them were made by Russians.
  其中有两个半是由俄罗斯人完成的。

[01:50] In 1905, when he wrote his first and most important work, he was only 26 years old.
  1905年，当他写下他的第一部也是最重要的著作时，他才26岁。

[01:59] So why are these three revolutions so important?
  那么，这三次革命为什么如此重要呢？

[02:01] The reason is that by the end of the 19th century, physicists were studying what was called microscopic physics, which is macroscopic physics.
  原因是到19世纪末，物理学家们研究的是所谓的微观物理学，也就是宏观物理学。

[02:10] What is macroscopic physics?
  什么是宏观物理学？

[02:11] It's the physics of a centimeter, a kilometer, or even a millimeter.
  它是关于厘米、公里甚至毫米的物理学。

[02:21] The founders of this kind of physics were, of course, Galileo and Newton.
  这种物理学的创始人当然是伽利略和牛顿。

[02:26] By the end of the 19th century, microscopic physics was extremely successful.
  到19世纪末，微观物理学取得了极大的成功。

[02:32] However, at the end of the 19th century, many new phenomena were discovered that could not be explained by Newtonian physics.
  然而，在19世纪末，发现了许多牛顿物理学无法解释的新现象。

[02:37] This is called microscopic physics.
  这被称为微观物理学。

[02:40] The most important thing about physics is that when you get to the size of an atom, which is 10 to the power of 8 centimeters, these phenomena can no longer be explained by Newtonian physics.
  物理学最重要的一点是，当你涉及到原子的大小，也就是10的8次方厘米时，这些现象就无法再用牛顿物理学来解释了。

[02:55] So at the end of the 19th century, in the last 10 to 20 years, many very strange problems arose in physics.
  因此，在19世纪末，在过去的10到20年里，物理学中出现了许多非常奇怪的问题。

[03:03] The final solution to these problems was the three great revolutions in the early 20th century that I just mentioned.
  这些问题的最终解决方案是二十世纪初我刚才提到的三次伟大的革命。

[03:11] The impact of this revolution was not only on physics, but also on the entire human race.
  这场革命的影响不仅在于物理学，还在于整个人类。

[03:17] For example, today, electricity, network communications, and of course, the explosion of atomic nuclei, all of these...
  例如，今天，电力、网络通信，当然还有原子核的爆炸，所有这些……

[03:28] All of this is based on the three major concepts.
  所有这些都基于三个主要概念。

[03:33] You can also say that this book and some other translated physics books I read at the time had a great impact on me.
  你也可以说，这本书和我当时读过的其他一些翻译的物理学书籍对我产生了巨大的影响。

[03:43] I was shocked and felt that this was something worth studying.
  我感到震惊，并觉得这是值得研究的东西。

[03:52] In 1937, the Anti-Japanese War broke out and my family left Tsinghua University.
  1937年，抗日战争爆发，我的家人离开了清华大学。

[03:58] My father went to teach at Southwest Associated University, a school combined with Peking University, Tsinghua University, and Nankai University.
  我父亲去西南联合大学任教，这是一所由北京大学、清华大学和南开大学合并而成的学校。

[04:05] In Kunming.
  在昆明。

[04:07] My father went there to teach, so our family moved to Kunming.
  我父亲去那里教书，所以我们全家搬到了昆明。

[04:10] Then in the summer of 1938,
  然后，在1938年的夏天，

[04:12] I was in my second year of high school,
  我上高中二年级，

[04:18] but I had not graduated from high school.
  但我还没有高中毕业。

[04:19] At that time, the Chongqing Ministry of Education discovered that there were too many middle school students who were homeless and didn't finish college,
  那时，重庆教育部发现有太多失学的中学生，

[04:27] so they told me that you don't need a high school diploma to take the college entrance exam.
  所以他们告诉我，参加高考不需要高中毕业证。

[04:34] It's called equivalent qualifications, so I took the exam and was admitted to Southwest Associated University.
  这叫做同等学力，所以我参加了考试，并被西南联合大学录取了。

[04:42] Since I didn't study in the last year and a half of middle school,
  由于我没有学习初中最后一年半的课程，

[04:47] I hadn't learned high school physics.
  我没有学过高中物理。

[04:47] So when they had to take the exam, I applied for chemistry.
  所以当他们必须参加考试时，我申请了化学。

[04:53] Since I had learned high school chemistry, I was admitted to the chemistry department.
  由于我学过高中化学，我被化学系录取了。

[04:54] But to apply for the chemistry department, you also have to take the physics exam,
  但是申请化学系，你还必须参加物理考试，

[05:00] so I borrowed a high school physics book and locked myself at home for a month,
  所以我借了一本高中物理书，把自己锁在家里一个月，

[05:04] desperately trying to learn everything in high school physics.
  拼命学习高中物理的一切知识。

[05:07] After that, I found that physics was very interesting.
  之后，我发现物理学非常有趣。

[05:11] To me, it was even more interesting than chemistry.
  对我来说，它比化学更有趣。

[05:14] So when I was admitted to Southwest Associated University, I immediately transferred from the Chemistry Department to the Physics Department.
  所以当我被西南联合大学录取时，我立即从化学系转到了物理系。

[05:20] There is another point about this that I think is worth mentioning to you young students today.
  关于这一点，我认为值得今天向你们这些年轻的学生提一下。

[05:26] I remember very clearly that when I was studying high school physics, I saw such a question.
  我清楚地记得，在我上高中物理课时，我看到了这样一个问题。

[05:31] This was my admission ticket at the time.
  这当时是我的入学凭证。

[05:33] Hahaha, in high school physics, everyone discussed a question:
  哈哈哈，高中物理学中，大家讨论了一个问题：

[05:43] if there is a fulcrum that is the circle rotating there, then the book explained that it has an acceleration called a Acceleration is equal to the square of the velocity divided by the radius.
  如果有一个支点是那个旋转的圆，那么书上解释说它有一个加速度叫做加速度等于速度的平方除以半径。

[05:57] When I read this paragraph, I was very confused.
  当我读到这一段时，我非常困惑。

[06:01] I felt that this was not right.
  我觉得这不对。

[06:02] Why?
  为什么？

[06:03] Because when this thing is rotating, of course it is rushing toward the top.
  因为当这个东西在旋转时，它当然是冲向顶部的。

[06:04] For example, when it rotates upward, it is rushing toward that direction
  例如，当它向上旋转时，它就冲向那个方向

[06:07] But the book says that its acceleration is centripetal, it is rushing inward.
  但书上说它的加速度是向心加速度，它是在向内冲。

[06:12] So when it is rotating like this, I feel that it is rushing like this, but the book says that its force is not downward.
  所以当它这样旋转的时候，我感觉它是在这样冲，但书上说它的力不是向下的。

[06:19] So, at first, I felt that I couldn't understand this.
  所以，一开始，我觉得我不能理解这个。

[06:20] I didn't say that it was wrong, but I felt that it didn't conform to my intuitive concept.
  我不是说它错了，但我感觉它不符合我的直观概念。

[06:31] Later, after thinking about the book carefully, I finally understood that what is talked about in physics is a vector, which is different from ordinary quantities.
  后来，仔细思考了书上的内容后，我终于明白了物理学中所说的矢量，它与普通量是不同的。

[06:40] I think everyone who has studied physics here will understand the importance of vectors.
  我想在这里学过物理的每个人都会明白矢量的重要性。

[06:46] How can we cancel that thing?
  我们怎么能抵消那个东西呢？

[06:49] This experience taught me a lesson.
  这次经历给了我一个教训。

[06:53] This lesson is that if you have intuition, you know, everyone has many intuitions in their life.
  这个教训是，如果你有直觉，你知道，每个人一生中都有很多直觉。

[07:00] This intuition can be said to be possessed by a two-year-old or three-year-old child.
  这种直觉可以说是一个两岁或三岁的孩子所拥有的。

[07:04] Why?
  为什么？

[07:05] Because a three-year-old knows that if there is a table, if
  因为一个三岁的孩子知道，如果有一张桌子，如果

[07:09] He tries to walk towards it, he will bump into it.
  他试图走向它，他会撞到它。

[07:14] So, in order to survive, a two-year-old and a three-year-old have a lot of understanding of the relationship between the environment and himself.
  所以，为了生存，两岁的孩子和三岁的孩子对环境与自身的关系有很深的理解。

[07:18] This is a kind of intuition.
  这是一种直觉。

[07:20] So when I say that when turning, he rushes forward.
  所以当我说的当转弯时，他向前冲。

[07:23] This is also a very natural intuition.
  这也是一种非常自然的直觉。

[07:25] When your intuition conflicts with the knowledge in the book, you must pay attention because this is the best learning opportunity.
  当你的直觉与书本上的知识相冲突时，你必须注意，因为这是最好的学习机会。

[07:32] You can't give up.
  你不能放弃。

[07:33] What does it mean to not give up?
  不放弃意味着什么？

[07:34] It means that you have to understand this point clearly.
  这意味着你必须清楚地理解这一点。

[07:36] Just like what I said just now, I don't just want to understand why it is written in the book as v square divided by You also have to understand its spirit.
  就像我刚才说的，我不仅仅想理解为什么书上写的是v方除以你，你还必须理解它的精神。

[07:45] This spirit is what I finally understood.
  这种精神是我最终理解的。

[07:45] It is a vector.
  它是一个向量。

[07:48] Speed ​​and acceleration are vectors, not ordinary quantities.
  速度和加速度是向量，而不是普通量。

[07:53] This understanding was very inspiring to me later.
  这种理解后来对我启发很大。

[07:55] In other words, after understanding this, I made some corrections to my intuition.
  换句话说，在理解了这一点之后，我对我的直觉做了一些修正。

[08:02] You can also say that learning is actually constantly correcting your intuition.
  你也可以说，学习实际上是不断地修正你的直觉。

[08:07] If you can continue to correct it in the right direction,
  如果你能朝着正确的方向继续修正它，

[08:10] Then you have one more way of thinking than those who don't correct it.
  那么，你比那些不纠正它的人多了一种思考方式。

[08:18] When I was at Southwest Associated University, I had many outstanding classmates.
  我在西南联合大学的时候，有很多优秀的同学。

[08:24] When I was in graduate school, there were only six classmates in the physics department.
  我读研究生的时候，物理系只有六个同学。

[08:29] Three of them are in this photo.
  他们中有三个人在这张照片里。

[08:32] The one on the far left is Huang Kun.
  最左边的是黄昆。

[08:34] Huang Kun later became a master of solid-state physics.
  黄昆后来成为固体物理学大师。

[08:38] He returned to China in the 1950s and made important contributions to China.
  他于20世纪50年代回到中国，为中国做出了重要贡献。

[08:42] He made extremely important contributions to physics.
  他对物理学做出了极其重要的贡献。

[08:48] Why?
  为什么？

[08:49] Because everyone knows that semiconductors are an indispensable field in today's industry.
  因为大家都知道，半导体是当今工业中不可或缺的领域。

[08:55] Semiconductors were not developed until the 1950s.
  半导体直到20世纪50年代才得到发展。

[08:57] It was Huang Kun who started developing internationally in the 1950s when he opened a training course in China on semiconductors.
  正是黄昆在20世纪50年代在中国开设了半导体培训课程，开始了国际化发展。

[09:12] Chinese universities, research institutes, and factories are his disciples.
  中国的大学、研究所和工厂都是他的门生。

[09:21] In 2000, President Jiang Zemin personally awarded him the largest award in Chinese science for his contributions.
  2000年，江泽民主席亲自授予他中国科学界的最高奖项，以表彰他的贡献。

[09:30] The person in the middle is Zhang Shoulian.
  中间那位是张守廉。

[09:32] He later changed his career from physics to electrical engineering and made important contributions to this area.
  他后来从物理学转到电机工程学，并在此领域做出了重要贡献。

[09:38] The person on the right is me.
  右边那位是我。

[09:40] This photo was taken in 1992 when Mr. Zhou Peiyuan turned 90.
  这张照片摄于1992年，周培源先生90岁寿辰之际。

[09:45] There was a celebration at Peking University, and the three of us went.
  北京大学举行了庆祝活动，我们三个人都去了。

[09:49] When we were at Southwest Associated University, we often gave eloquent speeches, which attracted a lot of attention.
  我们在西南联合大学时，经常发表精彩的演讲，引起了广泛关注。

[09:55] So, someone took this photo of us, the Three Musketeers, in 1992.
  所以，有人在1992年拍下了我们——三剑客的照片。

[10:04] Huang Kun passed away in 2004, but Zhang Shoulian is now 92 years old and still alive and studying.
  黄昆于2004年去世，但张守廉现年92岁，仍然健在并继续学习。

[10:13] I later described our life situation in the book like this:
  我后来在这本书中这样描述了我们的生活状况：

[10:16] We debated endlessly about various issues in physics.
  我们就物理学的各种问题进行了无休止的辩论。

[10:20] I remember one time we were arguing about the precise meaning of measurement in quantum mechanics.
  我记得有一次我们正在争论量子力学中测量的精确含义。

[10:26] This was a significant and subtle contribution of the Cohen-Hagen School, and a foundational theory in quantum mechanics.
  这是科恩-哈根学派一项重要而微妙的贡献，也是量子力学中的一项基础理论。

[10:38] The debate continued from the moment we started drinking tea that day until we returned to Kuanghua Middle School that evening, turned off the lights, and went to bed.
  这场辩论从那天我们开始喝茶的那一刻起，一直持续到那天晚上我们回到光华中学，关上灯，上床睡觉。

[10:44] Why was that?
  为什么会这样呢？

[10:45] The three of us lived in the same dormitory at the time.
  当时我们三个人住在同一个宿舍里。

[10:47] The New Year's Eve party was very simple.
  年夜饭聚会非常简单。

[10:50] We didn't have boiled water to drink, so how did everyone get water?
  我们没有开水喝，那大家是怎么弄到水的呢？

[10:54] We went to the teahouse after dinner.
  晚饭后我们去了茶馆。

[10:55] There were many teahouses around Southwest Associated University, all occupied by students.
  西南联合大学周围有很多茶馆，都被学生们占满了。

[11:00] In those teahouses, you could order Pu'er tea, scented tea leaves, or glass tea.
  在那些茶馆里，你可以点普洱茶、花茶或者玻璃茶。

[11:08] What was glass tea?
  什么是玻璃茶？

[11:09] It was a cup of water without tea leaves.
  就是一杯没有茶叶的水。

[11:14] At that time, we were all in these teahouses, debating about all sorts of issues, including physics.
  那时，我们都在这些茶馆里，争论各种各样的问题，包括物理学。

[11:26] I can't remember the exact details of the debate that night, or who held which view, but I clearly remember that the three of us finally got out of bed, lit candles, and used the physical principles of Frank Heisenberg's quantum theory to guide our debate.
  我不记得那个晚上辩论的具体细节，或者谁持什么观点，但我清楚地记得，我们三个人终于起床，点燃蜡烛，并运用弗兰克·海森堡量子理论的物理原理来指导我们的辩论。

[11:45] I received my master's degree at Southwest Associated University in 1944, and the war ended a year later.
  我于1944年在西南联合大学获得了硕士学位，一年后战争结束了。

[11:52] So in the summer of 1945, I traveled through India to the United States and entered the University of Chicago.
  因此，在1945年夏天，我经印度前往美国，进入芝加哥大学。

[11:58] Why did I go through India?
  我为什么经印度去？

[11:59] Because the war had just ended, there were no air routes, no shipping routes, and the only way to get from Kunming to the United States was to take a small US military plane from Kunming to Calcutta.
  因为战争刚刚结束，没有空中航线，也没有航运路线，从昆明到美国的唯一方式是乘坐一架小型美国军用飞机从昆明飞往加尔各答。

[12:16] Then, a group of 20 of us, sponsored by the Tsinghua University, went to the United States.
  然后，我们一行20人，由清华大学资助，去了美国。

[12:20] It was also founded by the Tsinghua Foundation in 1911.
  它也是由清华基金会于1911年创立的。

[12:31] After 1925, there were six entrance exams for students to study in the United States.
  1925年后，有六次入学考试供学生在美国学习。

[12:35] The last one was held in 1943.
  最后一次考试于1943年举行。

[12:39] I took the exam, and when the results were announced, about 20 people received the scholarship.
  我参加了考试，当公布结果时，大约有20人获得了奖学金。

[12:46] So we were on the same ship, and flew from Kunming to Calcutta in August 1945.
  所以我们同乘一艘船，于1945年8月从昆明飞往加尔各答。

[12:54] We waited in Calcutta for two months until there were some empty seats on the American troop transport.
  我们在加尔各答等了两个月，直到有空位在美军运输船上。

[12:59] We boarded that ship, passing through the Red Sea and the Mediterranean Sea, and arrived in New York on November 24, 1945.
  我们登上了那艘船，经过红海和地中海，于1945年11月24日抵达纽约。

[13:10] After arriving in New York, I first wanted to go to Columbia University because I wanted to find
  抵达纽约后，我首先想去哥伦比亚大学，因为我想找

[13:17] A physicist whom I admired very much, named Firmy.
  一位我很敬佩的物理学家，名叫菲尔米。

[13:21] Later, I found out that he was not at Kramer University.
  后来，我发现他不在克莱默大学。

[13:24] Finally, I found out that he went to Chicago, so I entered the University of Chicago in early 1946.
  最后，我发现他去了芝加哥，所以我于1946年初进入了芝加哥大学。

[13:31] I was a graduate student at Zhejiang University for two and a half years.
  我在浙江大学读了两年半的研究生。

[13:33] Was it smooth sailing?
  一切顺利吗？

[13:35] It was not.
  并非如此。

[13:37] In 1947, when I was a graduate student for more than a year, because as I just mentioned, I worked on several problems given to me by Taylor, but none of them suited my taste.
  1947年，当我读研究生一年多的时候，因为正如我刚才提到的，我处理了泰勒给我的几个问题，但没有一个合我口味。

[13:48] So at that time, on the way from China to the United States, I told myself that physics is based on experiments.
  所以那时，在从中国到美国的路上，我告诉自己，物理学是基于实验的。

[13:59] I didn't have the opportunity to learn experiments in China, so I said that I must write an experimental paper when I go to the United States.
  我在中国没有机会学习实验，所以我说，去美国时我必须写一篇实验论文。

[14:09] So when I arrived in Chicago, I did some research with Taylor.
  所以当我到达芝加哥时，我和泰勒一起做了一些研究。

[14:12] After it was unsuccessful, I found an experimental physics professor.
  在不成功之后，我找到了一位实验物理学教授。

[14:17] named Allison to work in his laboratory.
  名叫艾莉森在我的实验室工作。

[14:22] I soon discovered that I, my classmates, and my supervisor also discovered that I was not good at hands-on work.
  我很快发现，我和我的同学们，还有我的导师，也都发现我并不擅长动手工作。

[14:30] When I did it, I often broke the equipment.
  当我做的时候，我经常弄坏设备。

[14:35] So at that time, I was at a low point.
  所以那时，我处于低谷。

[14:38] I wrote a letter to Huang Kun.
  我给黄昆写了一封信。

[14:41] I just introduced Huang Kun to you.
  我刚才向你们介绍了黄昆。

[14:43] He was a graduate student in the UK at that time.
  他当时是英国的一名研究生。

[14:45] I wrote him a letter, and there was this sentence in the letter.
  我给他写了一封信，信中有这样一句话。

[14:49] It can be said that I was disillusioned, which means my ideals were extinguished.
  可以说我感到幻灭了，这意味着我的理想破灭了。

[14:55] Then, as for the letter I wrote to him, he burned it when he returned to China during the Cultural Revolution.
  然后，至于我写给他的那封信，他在文革期间回国时把它烧了。

[15:03] I think everyone understands the situation at that time.
  我想大家都明白当时的情况。

[15:06] Fortunately, he wrote me a very long letter in reply.
  幸运的是，他给我写了一封很长的回信。

[15:08] I found this very long letter in my archives a few years ago.
  几年前我在我的档案里找到了这封很长的信。

[15:14] So from the letter Huang Kun wrote to me, I can recall that I
  所以从黄昆写给我的信中，我能回忆起我

[15:18] I felt that my future was a little bleak in 1947.
  我感觉我1947年的未来有些黯淡。

[15:27] So, what did I do under such circumstances?
  那么，在这种情况下我做了什么？

[15:29] So I decided to develop my own topic.
  所以我决定发展我自己的课题。

[15:33] I found three topics at first.
  我最初发现了三个课题。

[15:36] One was called isomod, one was called Betas work, and one was called Geometer.
  一个叫isomod，一个叫Betas work，还有一个叫Geometer。

[15:42] Isomod was a very famous Swedish physicist who later came to the United States.
  Isomod是一位非常著名的瑞典物理学家，他后来来到了美国。

[15:50] His name was Onsaka.
  他的名字叫Onsaka。

[15:52] He published an amazing article.
  他发表了一篇惊人的文章。

[15:55] This article was very famous, so I tried to study how he wrote it.
  这篇文章非常有名，所以我试图研究他是如何写的。

[15:58] The article was not long, about ten pages.
  这篇文章不长，大约十页。

[16:01] After studying it for a few weeks, I still didn't understand it.
  研究了几周后，我仍然不理解它。

[16:05] His article was just one formula after another.
  他的文章就是一个公式接一个公式。

[16:08] You just followed his instructions for a dozen pages, and then suddenly you got the result.
  你只需要按照他的说明写十几页，然后突然你就得到了结果。

[16:12] You didn't understand why he was flipping around like that.
  你不明白他为什么那样翻来覆去。

[16:16] So this was not an understanding.
  所以这不是一种理解。

[16:16] After studying it for a few weeks, I
  研究了几周后，我

[16:19] admired his ability very much, but I didn't learn anything.
  非常钦佩他的能力，但我没有学到任何东西。

[16:24] Another thing I was studying at the time was Beta's work.
  当时我研究的另一件事是贝塔的工作。

[16:27] Beta is the one I just mentioned.
  贝塔就是我刚才提到的那个人。

[16:29] Onsaka and Beta both won Nobel Prizes.
  翁萨卡和贝塔都获得了诺贝尔奖。

[16:32] Beta's 1931 work on spinways is quite famous.
  贝塔1931年关于自旋的著作相当有名。

[16:38] It involves complex mathematical deductions, and I've been studying it for a long time, but I haven't been able to come up with any results.
  它涉及到复杂的数学推导，我研究了很长时间，但一直没有得出任何结果。

[16:45] I think it took everyone about a month or two.
  我认为这花了大家大约一两个月的时间。

[16:49] The third topic is called Gauge Invariance.
  第三个话题叫做规范不变性。

[16:53] Today, I found a few pages of notes from March 1947 in my archives.
  今天，我在我的档案中找到了一些1947年3月的笔记。

[17:01] These are my thoughts at the time.
  这些是我当时的想法。

[17:05] What was this idea about?
  这个想法是关于什么的？

[17:06] There's a concept called Gauge Invariance, which was conceived by a great mathematician named Weyl in 1910.
  有一个叫做规范不变性的概念，它是由一位名叫韦尔的伟大数学家在1910年构思的。

[17:16] I wondered if this idea could be extended to the newly discovered
  我想知道这个想法是否可以推广到新发现的

[17:23] fundamental physics.
  基础物理学。

[17:25] This is the second page,
  这是第二页，

[17:26] and this is the third page.
  这是第三页。

[17:28] Gauge Invariance was a concept introduced by Weyl in 1918.
  规范不变性是外尔在1918年引入的一个概念。

[17:31] It was interesting but not very useful
  它很有趣，但用处不大

[17:33] in electromagnetism.
  在电磁学中。

[17:36] The new world at the time had many new examples,
  当时的新世界有很多新的例子，

[17:40] and I thought the forces between these new particles
  我想这些新粒子之间的力

[17:42] might be generalized.
  可能被推广。

[17:45] Perhaps the generalized Gauge Invariance could be used.
  也许可以推广规范不变性。

[17:49] In other words,
  换句话说，

[17:49] some new examples were discovered at that time,
  当时发现了一些新的例子，

[17:52] and it was not clear how they interacted with each other.
  但它们之间如何相互作用尚不清楚。

[17:54] Then there was Weyl's
  然后是外尔的

[17:58] sharp idea.
  绝妙想法。

[17:59] I thought at that time whether I could apply this to this.
  我当时想我是否能将此应用于此。

[18:02] This can be said
  这可以说

[18:04] to be the most important point of my success in life.
  是我一生中最成功的关键点。

[18:07] At that time, no one else thought so,
  当时没有人这么想，

[18:09] but I did.
  但我这么想了。

[18:10] So I went to study in this direction.
  所以我朝着这个方向去研究。

[18:12] This idea seemed to make sense,
  这个想法似乎有道理，

[18:14] but the more I calculated, the more complicated
  但计算越多，就越复杂

[18:16] it became.
  它变得。

[18:18] So after one or two months, I still didn't succeed.
  所以一两个月后，我仍然没有成功。

[18:19] So from the 123 method I just mentioned, each one
  所以从我刚才提到的123方法来看，每一个

[18:23] didn't produce any results after a few months.
  几个月后没有产生任何结果。

[18:25] But what I want to tell you is that all three of them produced results,
  但我想告诉你们的是，他们三个都取得了成果，

[18:30] but they were not successful at the time.
  但当时并不成功。

[18:34] What is the lesson? This unsuccessful attempt is not necessarily unreasonable.
  教训是什么？这次不成功的尝试不一定是不合理的。

[18:41] The last topic I found myself was angular distribution in nuclear reactions,
  我发现的最后一个课题是核反应中的角分布，

[18:45] which was also a popular experimental topic at the time.
  这在当时也是一个流行的实验课题。

[18:48] I combined it with theory and understood some phenomena.
  我将其与理论相结合，并理解了一些现象。

[18:53] So I wrote a very short article and showed it to Taylor.
  所以我写了一篇很短的文章，并给泰勒看了。

[18:58] The content of this article basically puts this into practice.
  这篇文章的内容基本上是将此付诸实践。

[19:02] I can give you a brief description of the application of the concept of scale to nuclear reactions.
  我可以简要描述一下尺度概念在核反应中的应用。

[19:11] We all know that there is a periodic table,
  我们都知道有一个元素周期表，

[19:13] which was discovered by Mendeleev in the 19th century.
  它是由门捷列夫在19世纪发现的。

[19:16] As you know, when you studied chemistry, you learned that its periods are 2, 8, and 18.
  如你所知，当你学习化学时，你了解到它的周期是2、8和18。

[19:21] Where did these 2, 8, and 18 come from?
  这些2、8和18是从哪里来的？

[19:23] At the time of Mendeleev
  在门捷列夫的时代

[19:26] and for many years afterwards, the source of these numbers was unknown.
  在之后的许多年里，这些数字的来源是未知的。

[19:30] It was just that after you filled in the table, it was naturally discovered that these numbers should exist based on the chemical structure.
  只是在填完表格后，人们自然而然地发现这些数字应该基于化学结构而存在。

[19:38] After the development of quantum mechanics, the principle of symmetry was used to understand 2, 8, and 18.
  在量子力学发展之后，对称性原理被用来理解2、8和18。

[19:43] These 2, 8, and 18 are basic numbers in group theory.
  这2、8和18是群论中的基本数字。

[19:47] In other words, group theory discusses a symmetry principle.
  换句话说，群论讨论的是对称性原理。

[19:50] So in other words, the number of these periods comes from the concept of symmetry in group theory.
  所以换句话说，这些周期的数量来自于群论中的对称性概念。

[19:56] This tells you that group theory has a decisive influence on the structure of matter.
  这告诉你群论对物质的结构有决定性的影响。

[20:04] So what I just said was that I did something at that time.
  所以刚才我说的是，我当时做了一件事。

[20:05] I caught a small end of the big influence, so I wrote this article.
  我抓住了巨大影响的一个小端，所以写了这篇文章。

[20:13] After I gave this article to Taylor to read, Taylor came to me one day when I was in the lab.
  我把这篇文章给泰勒看之后，有一天我还在实验室时，泰勒来找我。

[20:17] As I just said, I was working in the lab.
  正如我刚才所说，我当时正在实验室工作。

[20:17] He asked me, "Frank, because my informal name is Frank,"
  他问我，“弗兰克，因为我的非正式名字是弗兰克，”

[20:24] and he said, "Frank, I heard that your experiment was not very successful.
  他说，“弗兰克，我听说你的实验不太成功。

[20:27] Because I

[20:29] was very famous among the 200 graduate students

[20:30] at the University of Chicago at that time

[20:31] . Everyone knew that this person

[20:32] did a good job

[20:33] in theoretical work

[20:33] , but was very clumsy in experiments

[20:35] . So, when he knew that I was not successful

[20:37] , he came to

[20:38] me and asked, "Frank

[20:39] , is your experiment not successful

[20:41] ?" I said, "It was not very successful.

[20:42] " He asked, "Why do you have to

[20:44] write this experimental paper? I will use

[20:46] this very short article

[20:47] as your graduation thesis,

[20:50] and you can get a doctorate.

[20:51] " So after I said this,

[20:53] I was very surprised. I was very troubled.

[20:55] So I said thank you

[20:57] and I had to think about it

[20:59] . Why?

[20:59] Because my original intention was

[21:01] to write an experimental paper and

[21:03] I couldn't give up easily,

[21:04] so I went back and thought about it.

[21:06] Many years later,

[21:07] when I recalled this incident

[21:09] and wrote about it,

[21:10] I said that after thinking about it for a few days, I

[21:11] felt that he was right

[21:13] , so I made up my mind

[21:14] to accept his offer.

[21:16] After accepting it, I

[21:18] felt relieved.

[21:19] Why was I relieved?

[21:20] It was because I had been weighed down by this paper

[21:22] for a long time.

[21:23] So of course, it was

[21:25] great

[21:26] after making this decision.

[21:28] Now thinking about it,

[21:30] this decision is a very important point

[21:32] in my life . The lesson I learned from this

[21:35] is that if you are in a very difficult situation,

[21:38] you should think about whether you should change

[21:41] your career. When I was studying

[21:42] at Southwest University, There are many important professors at the United Nations.

[21:44] Looking back,

[21:46] there are two who have had the greatest influence on me.

[21:49] One is Professor Wang Zhuxi,

[21:51] who is 14 years older than me

[21:52] . He was a young

[21:54] professor who had just returned from the UK.

[21:56] The research direction he

[21:58] discussed

[22:00] was called statistical mechanics.

[22:01] What is statistical mechanics?

[22:03] As we all know, all matter

[22:05] is composed of atomic and molecular structures

[22:07] according to 19th-century physicists.

[22:10] There are countless atoms and molecules

[22:12] in every part of our body.

[22:14] These atoms and molecules move inside,

[22:16] and the result of this movement

[22:18] shows many phenomena.

[22:20] For example, the molecules and atoms in water

[22:23] move very vigorously.

[22:25] If you heat the water,

[22:27] it freezes even more.

[22:28] When it reaches 100 degrees Celsius,

[22:30] it freezes so hard that it

[22:31] becomes steam. So

[22:32] it turns into water vapor . So the

[22:34] movement of many atoms and molecules

[22:36] at different temperatures,

[22:39] this whole physical phenomenon,

[22:41] this research field

[22:42] is called statistical mechanics.

[22:44] This is Mr. Wang's research direction.

[22:46] So when I was about to graduate from university in 1931942,

[22:52] students at Southwest Associated University

[22:54] had to write

[22:57] a bachelor's thesis to get a bachelor's degree.

[22:58] The thesis did not have to be long

[23:00] , but it

[23:00] had to express what the student knew

[23:02] about a certain field

[23:04] . So I went to find Mr. Wang Zhuxi.

[23:07] I'm sorry, I said it wrong just now.

[23:08] This was when I was studying

[23:10] at the graduate school of Southwest Associated

[23:11] University and I was going to write my master's thesis,

[23:13] so I went to find Mr. Wang Zhuxi

[23:15] . The field he introduced to me is

[23:18] called statistical mechanics

[23:20] . One of the very important

[23:22] SUB The discipline

[23:24] is called phase change.

[23:25] I just said that the change from water to water vapor

[23:27] is one phase change

[23:28] . When water is cooled, it turns into ice

[23:30] , which is another phase

[23:30] change . Phase change is a very important phenomenon

[23:33] . My interest in statistical mechanics

[23:34] and phase change

[23:36] originated from Mr. Wang's leadership

[23:39] . This

[23:40] field

[23:40] later

[23:41] became the focus of one-third of my life's work.

[23:46] Another

[23:47] professor of physics at Southwest Associated University who had a great influence on me

[23:49] was Mr. Wu Dayou

[23:51] . This photo was of course not taken at the time. This photo was taken

[23:53] when I was 60 years old.

[23:55] There was an academic conference celebrating my 60th birthday

[23:56] at Stone Book.

[23:59] Mr. Wu was in Taiwan at the time.

[24:01] He specially came from Taiwan to visit my students.

[24:03] This photo was taken in my office .

[24:06] When

[24:08] I was studying for my bachelor's degree, I

[24:11] had to write a thesis.

[24:13] So I went to see Mr.

[24:15] Wu. He

[24:16] told me

[24:18] that there was an article about symmetry.

[24:20] I should study the article

[24:21] and write a

[24:23] thesis. This

[24:24] concept of

[24:25] symmetry

[24:26] exists in daily life,

[24:27] such as left-right symmetry

[24:28] or circular symmetry.

[24:30] The language used to

[24:33] apply this concept to physics

[24:34] and mathematics

[24:35] is called group

[24:36] theory. Group theory in mathematics and physics

[24:38] began in the 19th century. In

[24:40] the 20th century,

[24:41] group theory became

[24:43] one of the most basic languages ​​in

[24:46] physics and mathematics

[24:48] . Work related to group theory is one of the pillars

[24:50] of physics and mathematics in the 20th century

[24:52] . I am very grateful

[24:53] to Mr. Wu for guiding me into this field in 1942.

[25:00] I went to see Mr. Wu

[25:01] and told him that I wanted to be his student.

[25:03] When I was writing a thesis,

[25:05] he

[25:06] gave me a copy of Reviews of modern Physics

[25:08] asked me to study one of the articles.

[25:11] I'm currently reading

[25:12] from an article I wrote later

[25:14] to see what I learned .

[25:15] This article discusses

[25:17] the relationship between molecular spectroscopy and group theory.

[25:19] I took the article home to show my father.

[25:22] Although my father didn't study physics,

[25:24] he studied mathematics,

[25:25] and he knew a lot about group theory

[25:27] . So he gave me a small book written by Dixon

[25:29] called Modern Algebra Theory.

[25:32] Dixon was my father's teacher at the University of Chicago.

[25:34] The book was very concise and

[25:37] without any nonsense,

[25:38] which was exactly what I liked.

[25:40] In just 20 pages, he

[25:41] fully and beautifully explained

[25:45] the representation theory in weight theory.

[25:48] I learned

[25:49] the beauty of group theory and its in-depth application in physics,

[25:52] which had a decisive influence on my later work.

[25:55] This field can be called symmetry principle.

[25:58] My interest in symmetry principle

[26:00] actually originated from Mr. Wu's guidance that year.

[26:03] This is my lifelong interest.

[26:05] Thank you very much.

[26:08] This is a photo of Fermi.

[26:10] He was a master of physics in the 20th century

[26:14] , and he made a very important contribution

[26:16] that is closely related

[26:18] to the lives of everyone in the world today

[26:19] . He was the first

[26:21] to build the world's first reactor

[26:24] , proving that nuclear reactions

[26:28] can generate energy .

[26:30] Once energy is generated, there are two ways.

[26:32] One way is to generate it slowly, which can generate electricity.

[26:35] This is the origin of all current nuclear power generation.

[26:38] If you change the method

[26:39] to make them generate energy rapidly,

[26:42] of course, you can cause an explosion.

[26:43] This is the principle of atomic bombs and hydrogen bombs.

[26:47] The

[26:48] first successful

[26:51] release of nuclear energy under an artificial state was

[26:54] in December 1942, when

[26:56] Fermi built

[26:58] the first reactor at the University of Chicago .

[27:00] Today, the site of the reactor no longer exists

[27:03] because the reactor was originally like this.

[27:06] The University

[27:07] of Chicago

[27:08] was originally established in the United States

[27:12] around 1890 with donations from the Rockefeller family

[27:17] . After its establishment,

[27:18] the University of Chicago

[27:19] quickly became an important university.

[27:20] It had football

[27:21] and a football field

[27:22] , an American football field

[27:24] with a large stand.

[27:26] Then, in 1929,

[27:28] the University of Chicago had a new,

[27:30] young, 29-year-old president

[27:32] named Hawkins.

[27:33] At that time, the Americans called him "boy".

[27:36] He was

[27:36] against sports,

[27:38] saying there shouldn't be any sports at the university, so

[27:40] he disbanded the University of Chicago football team.

[27:44] This was a shocking thing at the time.

[27:47] After the disbandment,

[27:48] the stands were useless

[27:49] and just sat there.

[27:50] Then in 1942,

[27:52] the

[27:53] US

[27:55] government wanted to study

[27:57] whether they could build a reactor

[27:58] and extract materials from the reactor

[28:01] to make an atomic bomb.

[28:03] They needed a place to do this

[28:05] , so they

[28:06] built a reactor

[28:08] in the empty space under the unused

[28:10] football stands

[28:11] at the University of Chicago

[28:15] . Then in the 1950s,

[28:17] the reactor and

[28:17] the stands were completely removed.

[28:20] There's now a famous sculpture

[28:21] in that place .

[28:25] This sculpture commemorates the place where

[28:26] humanity first built a chimney.

[28:29] This is a masterpiece by the British architect

[28:32] Henry Moer

[28:34] . If you visit the University of Chicago,

[28:38] it's best to take a photo here.

[28:40] This is one of Henry Moer's masterpieces.

[28:45] I later expressed my deep regret for

[28:48] Phil Filmi, who unfortunately passed away in 1954 at

[28:50] the age of

[28:52] 53.

[28:52] At a celebration marking the 100th anniversary of his birth,

[28:56] I said these words:

[28:58] Andre Cohen

[28:59] is one of the most respected and admired

[29:01] of all the great physicists of the 20th century.

[29:04] He is respected and admired

[29:06] because of his

[29:07] contributions to both theoretical and experimental physics

[29:09] , because the work under his leadership

[29:11] has led to the discovery of powerful new energy sources for mankind

[29:14] , and more importantly, because of his personality

[29:17] . He is always reliable and trustworthy,

[29:20] always down-to-earth,

[29:21] and extremely capable

[29:23] , but he does not abuse his influence

[29:24] , seek popularity, or flatter others.

[29:27] I have always considered him to be a typical Confucian gentleman

[29:31] . I know many

[29:33] world-famous physicists,

[29:36] and he is very special in this respect

[29:38] . For example,

[29:39] there is another very famous physicist

[29:42] named Robert Oppenheimer.

[29:43] I am also very familiar with Robert Oppenheimer because

[29:45] he was Princeton's chief physicist during my 17 years at Princeton

[29:47] . The director of the Institute

[29:51] was a brilliant physicist

[29:55] with excellent eloquence.

[29:56] However, he was the complete opposite of Openheimer

[30:01] . He didn't focus on being practical;

[30:05] he wanted to show that he was a truly exceptional person.

[30:09] This was also related

[30:12] to his subsequent

[30:15] dismissal from the US government

[30:15] because he easily offended too many people.

[30:18] Besides his contributions to physics

[30:23] , as I just mentioned,

[30:24] Fermi

[30:25] was highly respected

[30:27] in both the American and global physics communities for his character

[30:33] . I learned a great deal about physics from Jimmy,

[30:36] as well as some of the methods used in physics.

[30:39] I once said this about Fermi: "

[30:42] We learned from Fermi that physics should not be a specialist

[30:45] subject;

[30:46] physics is to be built from the ground up, brick by brick,

[30:49] layer by layer.

[30:50] We learned that abstraction comes after detailed foundational work,

[30:53] not before. " We

[30:54] also learned in these lectures of Fermi's that he delighted

[30:57] in rather than aversion to simple numerical computation with

[31:01] a desk computer.

[31:02] When I was Fermi's student,

[31:03] there were no modern large

[31:05] computers;

[31:06] there were only hand-cranked

[31:08] computers.

[31:09] He

[31:11] was very interested in using

[31:14] hand-cranked computers for simple calculations.

[31:16] Besides the formal and informal classes,

[31:18] Ferdinand also devoted

[31:19] almost all his learned hours to the graduate students,

[31:21] at least that was the state of affairs before 1950.

[31:24] The conversations in these luncheons

[31:27] naturally covered a wide range of subjects. We observed Fermi

[31:31] as a somewhat conservative man

[31:32] with a very independent mind.

[31:34] We observed his dislike of pretension of whatever kind. Sometimes

[31:38] he would give general advice to us about our research work.

[31:41] I remember his emphasizing that as a young man,

[31:44] one should devote

[31:44] most of one's time to attacking simple practical problems

[31:47] rather than deep fundamental ones. I remember the last

[31:50] incident I talked about

[31:51] very clearly

[31:52] because we asked him whether one should study big problems

[31:55] or small problems

[31:57] . His answer was that one

[31:59] should spend most of one's time on small problems.

[32:01] Big problems can be studied,

[32:03] but one must be moderate. That is, after

[32:05] you have spent some time studying

[32:06] big problems,

[32:07] When

[32:10] there's no progress,

[32:12] you can't just keep

[32:15] hitting the wall and not turning back.

[32:18] Why do you do that?

[32:18] Because if you do that,

[32:19] you might end up going insane.

[32:22] Actually, I'm not just saying this casually.

[32:24] I've been in the United States for many years and I've known

[32:26] some students

[32:27] and colleagues who are too eager

[32:29] to do the most basic work,

[32:32] but end up not succeeding,

[32:33] so they end up having mental problems.

[32:35] This is a common phenomenon.

[32:39] At the University of Chicago,

[32:40] another person who had a huge influence on me

[32:42] was Edward Taylor.

[32:45] Edward Taylor was 14 years older than me and

[32:47] was already a very famous

[32:49] physicist.

[32:50] However, he was most famous after

[32:52] I got my doctorate from the University of Chicago

[32:54] and went to Princeton,

[32:56] because he was

[33:00] the most important person

[33:02] in the United States who discovered the principle of the hydrogen bomb . Everyone knows that the United States exploded

[33:07] an atomic bomb in 1945. The discovery of the

[33:09] atomic bomb actually stemmed

[33:11] from a physics phenomenon discovered in Germany

[33:14] in 1938 called fission.

[33:16] Fission

[33:17] is when an atomic nucleus, under the right circumstances,

[33:19] splits into two,

[33:20] releasing a lot of energy.

[33:22] Once this phenomenon occurred in 1938

[33:24] ,

[33:25] all physicists knew that it

[33:29] could be turned into a series of

[33:32] events, where one nucleus splits into two

[33:35] , and the resulting fragments

[33:35] can cause other nuclei to split as well.

[33:38] This is called a chain reaction. The development of a chain reaction

[33:39] may lead to an explosion.

[33:43] So it can be said that this discovery in 1938

[33:46] made physicists realize that they could make atomic piles

[33:50] and atomic bombs.

[33:51] However, it

[33:52] took four years of hard work.

[33:53] As I mentioned earlier, Fermi

[33:55] built the first reactor

[33:57] under his guidance in 1942.

[33:59] So after this reactor was built,

[34:01] the atomic bomb could be built.

[34:02] This

[34:03] concept was also

[34:04] known to all physicists.

[34:06] But the atomic bomb exploded

[34:07] in 1945.

[34:09] Of course, there was an immediate question

[34:10] : could there be an explosion a thousand times longer?

[34:14] This is called a hydrogen bomb

[34:15] .

[34:16] At that time, everyone guessed that this was possible. Both the United States

[34:19] and the Soviet Union wanted to advance in this area.

[34:23] At that time,

[34:25] I was Taylor's student

[34:26] . Taylor

[34:28] did not discuss this issue in school

[34:30] , but his most enthusiastic thing at that time

[34:32] was how to make a hydrogen bomb.

[34:34] However , there is a basic difference between the manufacture of

[34:37] hydrogen bombs and the manufacture of atomic bombs

[34:39] . You can also say that the manufacture of atomic bombs

[34:40] is basically a

[34:42] very long series of

[34:46] engineering problems

[34:47] . All small engineering problems had to be solved

[34:50] , but from the atomic bomb to the hydrogen bomb,

[34:52] in addition to a series of engineering problems,

[34:54] there was also a trick.

[34:56] If you don't understand this trick,

[34:58] you can't make the hydrogen bomb.

[34:59] It's not enough to just solve a lot of engineering problems

[35:02] to turn the atomic bomb into a hydrogen bomb

[35:04] . In the end ,

[35:06] the main person who solved this trick

[35:08] in the United States was Taylor.

[35:11] So now in the world,

[35:13] the hydrogen bomb

[35:15] made in the United States is called the Taylor-Ulam

[35:18] bomb . The Soviet

[35:20] Union also made a hydrogen bomb

[35:22] ,

[35:23] so now everyone calls the Soviet hydrogen bomb

[35:26] the Sakhrov

[35:28] bomb.

[35:29] I don't know if the students here know

[35:31] who made

[35:34] the Chinese hydrogen bomb.

[35:36] There are two people.

[35:37] One is called Deng Jiaxian

[35:38] and the other is called Yu Min.

[35:39] So now the international community calls the Chinese hydrogen bomb.

[35:42] The discovery of this trick is Deng Yu's bomb

[35:46] . This photo of me

[35:47] was taken in the 1980s.

[35:51] When I was Taylor's student,

[35:54] Taylor was only about 40 years old and

[35:55] was a very outstanding physicist.

[35:58] But later on, of course, he became very famous .

[36:02] The physics I learned at the University of Chicago

[36:04] is basically different from the physics I learned in China.

[36:07] There is a big

[36:08] difference between the two. I would like to introduce this point in particular

[36:10] . The physics I learned in China

[36:13] can be said to be the deductive method.

[36:14] What is the deductive method?

[36:15] It is to go from theory

[36:17] to phenomenon. What is the deductive method?

[36:19] It is the physics I learned at that time.

[36:21] For example, thermodynamics

[36:22] has the so-called first theorem of thermodynamics

[36:24] , the second theorem of thermodynamics, and the third theorem of thermodynamics

[36:26] .

[36:27] The teacher tells you what the

[36:29] theorem is , and then you deduce from this theorem

[36:31] what kind of phenomena should be based on this theorem.

[36:36] At the University of Chicago, these are not discussed.

[36:37] What everyone discusses at the University of Chicago

[36:39] is called induction.

[36:40] What is induction?

[36:41] It starts with new phenomena.

[36:44] Because in the past, some theories

[36:46] and phenomena in physics were very clear

[36:48] , but the layers There are endless new phenomena.

[36:50] What the University of Chicago pays attention to

[36:52] are these new phenomena.

[36:53] So the question is whether

[36:53] these new phenomena can be summarized

[36:56] to see if they are consistent with the existing theories.

[36:58] If they are consistent,

[36:59] then you understand the phenomenon.

[37:01] If they are not consistent,

[37:01] then it is even better. Perhaps you need a new theory.

[37:03] So the key point is

[37:05] to distinguish

[37:08] between phenomena and theories.

[37:10] Taylor

[37:11] has many new insights

[37:15] in this inductive method.

[37:17] He also has another characteristic.

[37:18] He likes to discuss

[37:19] even immature ideas

[37:21] with others.

[37:22] So you walk in the corridor and

[37:23] suddenly see him and

[37:24] say, "Okay, I have a very good insight today

[37:27] .

[37:27] What do you think?

[37:28] " What's the phenomenon of oxide

[37:30] ? When you discuss with him,

[37:31] if

[37:33] you

[37:34] think his view is wrong, he won't

[37:37] think you are unfriendly to him.

[37:40] He will be willing to discuss with you

[37:41] .

[37:42] If there is a result, it

[37:43] may become a valuable article.

[37:46] This is his working method .

[37:48] I often tell my classmates

[37:49] that we who are trained

[37:50] in the Chinese education tradition

[37:54] need to pay attention

[37:55] to this method

[37:55] . Because

[37:56] there is a saying in the Chinese education tradition that "to know what you know and to know what

[37:59] you don't know is

[37:59] to know". What does this mean?

[38:02] It means that you have to figure out

[38:03] what you understand

[38:04] and what you don't understand.

[38:05] If you don't understand something

[38:07] , don't talk about it .

[38:09] This is in line with Taylor's spirit.

[38:12] It's the opposite,

[38:14] right?

[38:16] Of course it makes sense

[38:17] . If you keep hoping

[38:21] to distinguish

[38:21] what you understand

[38:22] and what you don't ,

[38:23] you will understand a lot of things

[38:24] during this step.

[38:26] So this instruction

[38:28] makes sense.

[38:30] But if you take this instruction too seriously and

[38:33] trust it too much

[38:34] , it won't be good. Why?

[38:36] Because there are many things you don't quite understand.

[38:38] When you don't understand something,

[38:40] things will slowly ferment.

[38:42] So I always tell my graduate students that

[38:44] there are some colloquialities in the school that

[38:46] you must listen to.

[38:47] It doesn't matter if you don't understand it the first time

[38:49] . If you listen again the second time,

[38:50] you may feel that you understand a little more.

[38:51] After

[38:52] listening a few times,

[38:53] you may gradually understand it.

[38:55] I call this the osmotic learning method.

[38:58] This osmotic learning method

[38:59] is not traditionally approved of in China

[39:01] , but

[39:02] I think it is a very important learning method.

[39:08] Taylor After giving me a short exam

[39:10] , he said, "You are very good .

[39:11] I will accept you as my student

[39:12] ." He gave me a topic .

[39:14] After working on it for a few months, I

[39:16] got some results .

[39:17] He was very proud

[39:18] of it

[39:19] and asked me to give a speech

[39:20] and then write it out.

[39:22] But I haven't written the article

[39:23] yet.

[39:25] Why?

[39:26] Because I found

[39:27] that the thing he taught me to do

[39:30] contained many approximations

[39:32] and a lot of

[39:34] imprecise data.

[39:37] When all these imprecise data were added together,

[39:39] I couldn't guarantee

[39:41] the final result,

[39:43] so I couldn't write it out.

[39:45] Taylor said it was okay

[39:46] and gave me another topic.

[39:47] The same phenomenon happened again.

[39:49] After changing the topics several times,

[39:53] the research atmosphere in the Department of Physics

[39:54] at the University of Chicago

[39:56] was very strong. There was a colloquium

[39:58] or several seminars every week.

[40:00] A seminar is a more specific colloquium. It

[40:02] usually involves inviting a famous person from another field

[40:05] to give a comprehensive report

[40:06] on an entire field

[40:09] . Its special feature

[40:11] is that it focuses on new phenomena and new methods,

[40:12] and less on textbook knowledge.

[40:15] For example, at the University of Chicago

[40:17] , during the two years I was there

[40:19] , several young people made some

[40:23] very important discoveries.

[40:24] One of them was a chemist

[40:26] named Liebie.

[40:27] He proposed a method

[40:29] called carbon fourteen dating.

[40:31] Before that,

[40:32] no one

[40:35] knew the age

[40:36] of archaeological discoveries,

[40:37] whether

[40:38] they

[40:40] were

[40:40] rocks or

[40:43] specimens,

[40:45] except for geological materials.

[40:46] So he came up with a

[40:48] method

[40:49] to use the radioactivity fixed in carbon

[40:51] to estimate the age of the excavated objects. This method ,

[40:54] called carbon fourteen dating,

[40:55] was a major revolution.

[40:57] Now,

[40:58] the world is paying attention to paleontology

[41:01] and even mining

[41:04] . Dating originated from a work at that time.

[41:07] So Libby later won a prize

[41:09] and a Robert Award.

[41:10] I also remember that the debate was very heated.

[41:13] Yuri

[41:15] was discussing how the organic molecules in the world

[41:18] first came into being.

[41:21] The earliest origin of life

[41:22] also became a small

[41:25] field in chemistry and biology.

[41:28] In terms of physics,

[41:29] the most popular topic of discussion at that time was

[41:31] the meson .

[41:32] There were several types of

[41:34] mesons

[41:36] . These

[41:37] were the hottest research topics at the time

[41:39] . At the University of Chicago,

[41:41] in

[41:41] this academic atmosphere,

[41:43] everyone was at ease in this

[41:47] kind of training. Among my classmates

[41:49] who received their PhDs between

[41:50] 1948 and 1950,

[41:54] four later won the Nobel Prize.

[41:57] This represents

[41:58] the academic atmosphere of the University of Chicago at the time

[42:00] and the exceptional success of

[42:03] the students trained there.

[42:06] Later, after visiting New China in 1971 ,

[42:10] I wrote an article in which

[42:11] I said that the courses taught in Chinese universities

[42:14] are often very advanced.

[42:15] There are the so-called four mechanics.

[42:17] Every physics student in a university

[42:18] has to spend a long time

[42:19] studying these four difficult theoretical courses.

[42:22] Are the four mechanics important?

[42:23] Of course they are.

[42:25] No one can deny that

[42:26] the four mechanics are the backbone of physics.

[42:28] However, physics is not just about the backbone. Physics with only the backbone

[42:30] is... A skeleton

[42:32] is not alive.

[42:33] Physics needs bones

[42:35] , flesh and blood.

[42:37] Physics with bones and flesh and blood is

[42:39] physics.

[42:42] I think what I said

[42:44] makes sense.

[42:46] Moreover, in the past few decades,

[42:50] the method of teaching physics in domestic universities

[42:52] has gradually

[42:53] moved away from the original

[42:56] method of over-emphasizing the four major mechanics.

[42:59] However,

[43:00] I think it is still not enough

[43:01] . When teaching physics

[43:03] in domestic universities,

[43:05] they still focus too much on the deductive method of the past

[43:09] and not enough on the

[43:11] inductive method. Hahaha.

[43:14] When I was in middle school, in Beijing Peking

[43:17] Middle School, and

[43:19] when I was studying at Kunming University

[43:20] , I was taught by a very good friend

[43:22] named Deng Jiaxian.

[43:24] I have already mentioned that

[43:25] China's later atomic bombs and hydrogen bombs

[43:27] were all taught by Deng Jiaxian. He made important contributions

[43:29] when he was studying in the United States

[43:32] from 1948 to 1950.

[43:33] We knew each other very well.

[43:34] One summer,

[43:35] he came from Peru

[43:38] to Chicago.

[43:39] He and I, my brother Yang Zhenping, and

[43:41] I rented an apartment

[43:42] and lived together for the whole summer.

[43:45] After he received his doctorate in 1950, he

[43:49] immediately returned to China

[43:50] and later became

[43:51] a person who made significant contributions to China's atomic bomb and hydrogen bomb.

[43:55] So when he passed away,

[43:56] General Zhang Aiping wrote these words

[43:58] : "Deng Jiaxian, the hero of the two bombs."

[44:02] After I received my doctorate in 1948, I

[44:05] worked as an instructor in Chicago for a year.

[44:07] Now people in the United States don't use this term anymore.

[44:09] In fact, it is equivalent to a

[44:12] A postdoc is a teaching postdoc.

[44:15] From 1949 to 1966,

[44:19] I worked at the Institute for Advanced Research

[44:21] for 17 years . The Institute for Advanced Research's

[44:24] most famous Instagram is, of course, Instagram.

[44:27] When I went to Instagram in 1949,

[44:29] Instagram had already retired.

[44:30] But he came to the office every day,

[44:33] so I knew when he would go out and

[44:34] where

[44:35] he would go . So in 1954,

[44:37] I took my son

[44:38] to this photo. I

[44:40] was walking down the street and asked Ashdan,

[44:42] "Can you take a photo

[44:43] with my child

[44:44] ?" It was really that photo

[44:47] .

[44:47] Instudio has always had very important professors in mathematics and

[44:50] physics

[44:52] ,

[44:53] including

[44:54] Gooder Polly, director

[44:56] Chen Shui-sheng, and

[44:57] Herman Byer

[44:58] Nilsson. Boer,

[45:00] the younger people

[45:01] are from my generation

[45:02] .

[45:02] This list is from

[45:05] 1949, the year I first went there.

[45:07] These people

[45:08] later became

[45:11] important figures

[45:12] in physics and mathematics . Among them, Gao Bennan and

[45:14] Li Dengdao

[45:15] both won the Nobel Prize.

[45:18] Why was IBM so successful?

[45:20] I think the first reason is

[45:20] that it was well-informed.

[45:22] The second reason

[45:22] is that everyone found their own

[45:23] forums. There was no saying who you worked with.

[45:26] Everyone was independent

[45:28] , but everyone

[45:29] could also find their own

[45:31] collaborators. I think if

[45:32] you

[45:34] have

[45:35] some smart and well-

[45:38] trained young people

[45:39] in such a competitive and cooperative unit with a lot of information, it

[45:42] would be easy for them to collide and come up with important new results.

[45:46] When I was there, I

[45:47] mainly worked on nuclear physics and particle physics.

[45:50] It was not just me.

[45:51] My colleagues at the time were all doing these things

[45:55] .

[45:56] I don't want to explain this part

[45:57] in detail . It was during this period that

[45:59] a colleague named Letenger,

[46:02] who was about the same age as me,

[46:04] happened to ask me

[46:05] if I had heard of any new developments in the IC model

[46:08] . I just told you about a model

[46:09] I worked on at the University of Chicago for several months

[46:11] without producing any results.

[46:12] They told me about a new development

[46:14] , and within ten minutes,

[46:16] while we were working on it,

[46:20] they explained the direction of this new development.

[46:24] Why was I able to absorb it so immediately

[46:25] ? It's because

[46:26] I'd spent months discussing

[46:28] it

[46:29] without understanding it,

[46:30] but now I knew some of the details.

[46:33] Now, a new development

[46:34] has connected all of these details.

[46:36] So, within ten minutes, I

[46:37] was

[46:39] able to understand this new key

[46:42] concept. In other words,

[46:43] if I hadn't put

[46:46] in those months of effort, I wouldn't have learned anything.

[46:48] And what I learned

[46:49] later had a huge

[46:50] impact on my work.

[46:53] Why?

[46:54] Because after I understood this,

[46:57] I performed a long calculation, the longest

[46:59] in my career of local tactical tricks.

[47:02] The calculation proceeded through twists and turns.

[47:05] There were many obstructions,

[47:08] but always after a few days,

[47:10] a new trick was somehow found that pointed to a new path.

[47:11] The trouble was that I

[47:15] soon felt I was in a maze

[47:17] and wasn't sure whether, after so many turns,

[47:20] I was anywhere nearer the goal than when I began

[47:24] this kind of strategic overview.

[47:25] I was very depressed and several times

[47:27] I almost gave up,

[47:28] but each time something

[47:29] drew me back, usually

[47:31] a new tactical trick that brightened the scene,

[47:33] even though only locally.

[47:35] Finally, after about six months of work off,

[47:37] and on all the pieces suddenly fitted

[47:39] together, producing miraculous cancellations

[47:42] , I was staring at the amazingly simple final result.

[47:46] This formula

[47:47] is just some simple polynomials,

[47:50] but it uses very complex

[47:53] mathematics to produce a result.

[47:55] This formula

[47:58] can be said to be my

[48:00] first famous paper in the physics community,

[48:03] because it was

[48:04] a very difficult problem that everyone knew at the time

[48:06] , and I solved it

[48:07] , and the result was beautiful.

[48:11] From this experience, I learned

[48:14] that you have to be interested in something,

[48:18] and that's my understanding of IC.

[48:20] Under the guidance of Mr. Wang Zhuxi,

[48:23] I became interested in this model

[48:24] . Then I went to the University of Chicago

[48:26] and did some preparation for a few months.

[48:27] The result was not successful at that time.

[48:30] But after having this,

[48:31] you can finally bear fruit

[48:34] when something new comes.

[48:35] I think this is a very important

[48:37] experience for my own research work.

[48:41] One-third of my life work is in statistical mechanics,

[48:43] including my work in the past two years

[48:45] . This field has developed in the past two years

[48:48] into a new field called radium atoms

[48:50] in the past ten years.

[48:52] Radium atoms are

[48:54] one of the two or three hottest fields

[48:57] in physics. This field

[48:58] is closely related to the statistical mechanics I did at the beginning.

[49:00] So now I have returned to this field

[49:02] in recent years

[49:03] to do cutting-edge research.

[49:06] Another interesting thing I did

[49:07] at the University of Chicago

[49:09] is the Gauge Invariance, which

[49:09] I mentioned just now.

[49:11] I have just told you that

[49:12] Gauge Invariance was introduced by Wahl in 1918.

[49:15] I have just shown you this slide.

[49:19] So in this, as I

[49:21] said just now,

[49:22] I continued to be interested in the direction of getting difference at the University of Chicago

[49:24] , but I could never get any results. The calculations became

[49:26] more and more complicated.

[49:28] From 1953 to 1954,

[49:30] I visited Brookhaven National Library for a year. I worked in

[49:32] the same office with a young man named Robert Mills.

[49:34] This photo was taken in 1999,

[49:36] when I retired at Stony Brook.

[49:38] The school organized a retirement symposium.

[49:41] Robert Miers came that day

[49:43] .

[49:44] I was sitting at a large

[49:45] dinner party.

[49:47] I was sitting at a table

[49:48] when Robert Miers arrived

[49:49] , so I stood up

[49:49] and someone took this photo of us.

[49:51] This is the only

[49:52] photo of Miers I have

[49:54] ever taken

[49:56] . He didn't tell me at the time

[49:58] that he had a clear cancer

[49:59] , so three months after

[50:02] this photo was taken, he was gone. He looks fine in this photo.

[50:05] Mills was five years younger than me

[50:07] and

[50:08] was very intelligent.

[50:09] The field he and I

[50:12] developed from gay theory

[50:14] is my most important work.

[50:17] This

[50:18] is actually very simple.

[50:20] The formula FMUNU

[50:22] in this formula is from Maxwell,

[50:24] a great 19th-century physicist and

[50:26] the most important physicist of the 19th century.

[50:29] Mills and I

[50:31] generalized this equation

[50:33] , and it became

[50:34] the following: AMU minus AMU. AMU

[50:38] is the reason why I was unsuccessful at first.

[50:41] When I was in Chicago,

[50:44] I didn't think of adding this term.

[50:46] So

[50:46] the equation I wrote was still the same as Maxwell's.

[50:48] This didn't work.

[50:49] When Music and I were working together,

[50:52] we asked if it didn't work, could you add one term

[50:54] ? Then it

[50:55] worked.

[50:56] This experience

[51:00] taught me a lesson

[51:02] : if you have a good idea,

[51:04] don't give up

[51:05] . As I said just now,

[51:07] don't get stuck in a dead end and work so

[51:09] hard that you drive yourself crazy.

[51:11] You

[51:11] can try

[51:12] it, but if it doesn't work, just

[51:13] give it up and do something else.

[51:14] After a few years,

[51:15] you may have new ideas

[51:16] , new phenomena

[51:17] , or new insights. Then try

[51:20] again.

[51:23] Don't give up completely.

[51:23] This is often effective.

[51:26] From 1955 to 1956,

[51:28] a big question in the physics community was

[51:31] called the Sitto puzzle

[51:32] . The mystery of Sitto

[51:33] is that at that time a particle called sit was discovered.

[51:35] After decaying, it turned into two factions.

[51:37] Another example called tall was discovered.

[51:39] It decayed into three factions.

[51:40] Of course, these are different things.

[51:42] These two decay in different ways

[51:45] . At that time, there were many kinds of basic examples.

[51:46] New discoveries

[51:47] all decayed differently,

[51:49] so they were all different.

[51:50] However, in another group of experiments

[51:52] , these CT and sets were taken for research.

[51:54] The research found that

[51:55] their masses were very close,

[51:58] with only a half percentage point difference

[52:01] . Usually, the ratio of the masses of two basic particles

[52:03] is very large

[52:04] , tens of thousands

[52:06] or even tens of thousands.

[52:07] The difference between these two things is so close,

[52:09] so this is very strange.

[52:10] Their lifespans are

[52:11] also basically the same.

[52:12] This is not very accurate

[52:14] , but within a 20% percentage, the

[52:15] lifespans are also the same.

[52:17] So some people say that

[52:18] these two are basically the same

[52:20] thing. It is a proton

[52:21] with two different decay methods,

[52:23] one is two factions

[52:23] and the other is three factions.

[52:25] But others say that

[52:26] according to the basic laws

[52:27] of physics , there

[52:28] is absolute left-right symmetry

[52:30] . Sit and talk cannot be the same example

[52:31] , so this is called sit and talk.

[52:34] This

[52:36] was the most important topic at

[52:36] that time . So

[52:39] when Li Dengdao and I were studying this problem

[52:42] in the summer of 1945 and 1956,

[52:43] we recently said

[52:44] that we would finally

[52:45] review

[52:48] the work that

[52:49] was previously believed to be absolutely symmetrical between left and right.

[52:51] After a few weeks of review,

[52:53] we made a surprising discovery.

[52:54] It turned out that the previous

[52:55] experiments that believed that left and right were absolutely symmetrical

[52:57] were all unfounded.

[52:59] At that time, no one had thought clearly.

[53:00] So we wrote an article

[53:02] saying that left-right symmetry

[53:04] had not been absolutely proven to be correct in the past,

[53:07] so this needed to be re-examined.

[53:09] Then

[53:10] we proposed which experiments should be done to

[53:12] solve this problem.

[53:15] Later, most physicists,

[53:19] almost all experimental physicists,

[53:21] were unwilling to do our experiments.

[53:22] Why?

[53:23] First, they believed that these experiments were very difficult.

[53:25] Second, if they were done,

[53:27] they would believe that the left-right symmetry was still proved.

[53:29] So this still could not solve the problem. TTO So

[53:31] , their achievement

[53:35] wouldn't have attracted global attention

[53:36] , so no one else was willing to do it.

[53:37] Only Chien-

[53:38] Shiung Wu,

[53:40] I later said, had a unique vision.

[53:43] He said the experiment should be done

[53:44] because it was an important topic,

[53:46] even if it didn't shock the world.

[53:48] That was his strength.

[53:51] This is his

[53:52] experimental equipment,

[53:53] which

[53:53] is now at the Smithsonian Institute in Washington.

[53:57] His collaborators were four Americans.

[54:01] I later wrote these

[54:03] words

[54:04] after Wu Chien-Shiung passed away: "Wu

[54:05] Chien-Shiung's work is renowned for its precision,

[54:08] but there's a more important reason for his success.

[54:10] " In 1956,

[54:12] no one else was willing to test the law of conservation of equilibria.

[54:15] Why was he willing to take on this difficult task?

[54:17] Because he had a unique vision

[54:19] and believed that even if the law of conservation of equilibria wasn't overturned,

[54:22] its fundamental law should be tested.

[54:24] That was his strength.

[54:29] The lesson I learned from this

[54:31] is that

[54:33] if there's a fundamental problem to be solved,

[54:36] you should tackle it.

[54:39] The 17 years from 1949 to 1966

[54:40] were the most fruitful of my research career.

[54:43] In 1966, I left Princeton to become

[54:44] director and professor of the Institute for Theoretical Physics at Stoddard Books.

[54:47] I left the Institute for Advanced

[54:48] Physics. Studying

[54:50] in an ivory tower

[54:52] is not easy.

[54:54] When I was doing internship , I

[54:59] was not clear about the relationship between

[55:02] the Gauge theory and mathematics.

[55:04] The head of the mathematics department during my internship at that time was

[55:08] Jim Simmons.

[55:10] One day,

[55:11] I discussed the gauge field formula with him.

[55:15] He said, "

[55:15] The gauge field formula

[55:17] in physics that you're working on

[55:19] has already been studied by us in mathematics,

[55:21] and it 's called a microscopic worm.

[55:23] "

[55:23] So, I asked him to explain cellulose to me

[55:26] .

[55:27] He gave us a series of

[55:29] informal discussions over lunch

[55:31] , which had a huge impact.

[55:34] After I understood this,

[55:35] Wu Daojun and I wrote an article.

[55:37] This article was read by physicists and mathematicians.

[55:40] Mathematicians generally began to understand

[55:41] that the structure of the gauge field

[55:43] is what is called a microscopic layer in mathematics.

[55:46] This photo of Simons was

[55:49] taken in 2001

[55:50] when I invited him to visit Tsinghua University.

[55:53] He left Sonnabook in 1980 and went to Wall Street, where he

[55:57] later became

[55:58] a billionaire.

[55:58] He is now

[56:00] one of the three most successful hedge fund managers

[56:03] on Wall Street.

[56:05] His hedge fund's income

[56:06] is

[56:08] in the billions of dollars each year.

[56:11] So, when I invited him to visit Tsinghua University,

[56:13] he donated a Children's Science Fund to me. Hall

[56:16] is now in use at Tsinghua University.

[56:24] Simons' explanation,

[56:27] along with the article I later wrote,

[56:29] sparked widespread interest in gauge fields in mathematics

[56:31] and the importance of topology in physics.

[56:34] This breakthrough in mathematics,

[56:36] in nematodes, has drawn widespread attention

[56:38] . An important

[56:41] figure in this field is Professor Chen Shensheng.

[56:43] Professor Chen Shensheng is 11 years older than me.

[56:45] He was in his nineties

[56:47] at Nankai University. This is

[56:48] a photo of us taken

[56:49] when he received an honorary degree in neurology.

[56:51] When

[56:54] I learned about the relationship between line bundles

[56:57] and gauge fields,

[57:00] I wrote this article

[57:01] and later reminisced about it.

[57:03] In 1975,

[57:04] the fact that gauge fields are connections on line bundles

[57:06] so excited me that

[57:07] I drove to

[57:08] Mr. Chen's home at SRTO near Berkeley. In

[57:12] the early 1940s, when I was a student at National Southwest Associated University

[57:15] and Chen Shenshen was a young professor,

[57:17] I took his lectures.

[57:18] That was before Chen Shenshen promoted the Cosine theorem

[57:21] and made historic contributions at the city level.

[57:23] Line-dimensional layers were not important in the dimensional hierarchy.

[57:26] We talked about friendship, family, and China.

[57:29] When we talked about fiber worms,

[57:30] I told him that

[57:31] I had learned from SIM. Simmons, I

[57:33] learned the beautiful fiberworm theory

[57:35] and the profound Hervey-Chenville theorem.

[57:39] I said that what astonished me most was that

[57:42] the normative length formalism manifested itself as a connection from above,

[57:44] and that mathematicians had

[57:46] come up with this without any practical reference to the physical world.

[57:49] I said that this

[57:50] both shocked

[57:51] and puzzled me,

[57:53] because you mathematicians

[57:54] could actually imagine these concepts out of thin air

[57:58] . He immediately objected, saying, "No,

[58:00] these concepts are not imaginary;

[58:02] they are natural and real.

[58:05] " Why the Creator chose natural and real,

[58:08] yet extremely abstract, mathematical concepts

[58:09] to construct the material world

[58:11] will probably remain a mystery forever. As

[58:15] you know,

[58:17] the great 18th-century poet William Blake

[58:20] once wrote, "To see a world

[58:23] in a grain of sand and heaven

[58:25] in a wildflower, hold infinity

[58:27] in the palm of your hand, and eternity in an hour."

[58:31] When physicists understand

[58:33] the original structure of the world,

[58:35] its ultimate structure

[58:36] combined with some very wonderful and

[58:38] refined mathematical principles,

[58:41] I think

[58:43] the feeling they get

[58:44] is similar to William Blake's when he wrote this poem.

[58:48] Professor Chen Zhifan translated William Blake's poem as follows

[58:50] : "There is a world in a grain of sand,

[58:52] a heaven in a flower

[58:54] , hold infinity in the palm of your hand

[58:57] , eternity is not just a moment of time."