Chapter 245 Talk Freely

"There are still many important unsolved problems in high-energy physics, and there are also some wonderful mathematical structures in superstring theory. If you are very interested in it, you might as well learn more about differential geometry and topology."

When talking to contemporary masters of theoretical physics, the topic will inevitably involve string theory, which is currently the most popular and most likely to become a grand unified theory of physics.

Although Mr. Yang is now 95 years old, he is still very energetic when talking about the fields he is familiar with. Wu Bin was very enlightened by the few points he occasionally mentioned.

"You look very interested?" Mr. Yang looked at Wu Bin and smiled slightly, as if he saw the flame of interest in his eyes.

"I'm interested in the unknown."

If you were an ordinary teacher, you would usually sigh when you meet someone like Wu Bin who does some research on everything, thinking that he can't get anything out of his head.

But the Yang Zhenning in front of me is different. He himself is the kind of person who has made great innovative contributions in multiple fields. How can he narrowly believe that scholars should spend their whole lives in one specialized field?

So Yang Zhenning was very happy to hear Wu Bin's answer and continued: "If you think this direction is right, you may be disappointed in the future because the idea of ​​superstrings has too little contact with actual physics."

"It seems more like a mathematical problem now." Wu Bin said after thinking for a while.

"Yes, but in my academic career, I have seen too many theories that have little contact with actual physics and are difficult to succeed in the end."

Taking a sip of hot tea, Yang Zhenning continued: "But the digital structure of superstrings is very wonderful. If you can absorb the subtleties inside, it may be helpful for you to develop some ideas that truly solve problems in the future. From this standpoint If so, I suggest you go for superstrings."

Mr. Yang spoke in a leisurely manner, but his tone still revealed some disapproval of superstring theory.

"I'll give it a try." Wu Bin nodded seriously.

Yang Zhenning nodded slightly after listening: "There are very few examples of insights derived from abstract mathematics that can be greatly successful in physics. I hope you can understand this before researching."

From Mr. Yang's words, Wu Bin read that he was afraid that he would be disappointed if he found nothing after studying superstrings, so he answered directly:

"Actually, I personally am not very entangled in the right or wrong results. What I pursue is just the fun of participating in it."

"Hahaha."

There was a burst of rhythmic laughter, and the expression on Yang Zhenning's face revealed some satisfaction.

After laughing, Yang Zhenning picked up a notebook placed on the coffee table, then took out the pen inserted in his jacket pocket and started writing on it.

[Mathematics (1)]-[Theoretical structure of physics (2)]-[Part combining theory and experiment (3)]-[Experiment (4)]

Pushing the notebook in front of Wu Bin, Yang Zhenning continued: "This is the relationship between mathematics, theoretical physics and experiment, and the combination of 2 and 3 is theoretical physics. A pure theoretical structure is connected to the experiment through the second part. "

Hearing this, Wu Bin couldn't help but pick up the topic, "But if pure structure cannot be connected with experiments for a long time, will it inevitably lose its status in physics..."

Yang Zhenning smiled and nodded after listening: "Yes, the value concept in physics ultimately comes from experiments. The reason why superstrings are so controversial is because they have not been connected to experiments through the second part. "

Looking at Wu Bin's thoughtful expression, Yang Zhenning continued: "There were students who debated with me in the United States. They said that when I did gauge field theory in 1954, wasn't it also a pure structure that had nothing to do with experiments?"

Changing his posture, Yang Zhenning continued: "Indeed, it did not have much to do with experiments at that time, but if they had read my article carefully, they would find that it was closely related to two theoretical structures that already had a solid experimental foundation. There is a close relationship, they are..."

"Isospin conservation and Maxwell's equations?" Wu Bin couldn't help but rush to answer.

"Hahaha."

After listening to Wu Bin's "answer", Yang Zhenning burst into rhythmic laughter again, looked at Wu Bin happily and said: "I really wish you were sitting down when I talked about this topic in class last time."

After being praised, Wu Bin smiled shyly and said, "I also hope to be lucky enough to listen to Professor Yang's class once."

"Alas..." Yang Zhenning sighed softly, shook his head and said: "In the past few years, I could take a group of students to class, but now I don't have the physical strength."

After speaking, looking at Wu Bin who was about to speak, Yang Zhenning waved his hand: "Don't say any polite words about me looking young. I understand my own body very well. Let me tell you about you. I heard that you have already Have you studied all the four major mechanics in college?"

Wu Bin shook his head and replied: "I can only say that I have a superficial understanding, I dare not say that I have completed the study."

"Very humble." Yang Zhenning took a sip of tea and continued: "In 1971, I returned to China many times and found that the so-called "four major mechanics" in the physics department were overwhelming the students. , Of course, I do not deny the importance of the four major mechanics. They are the backbone of physics, but physics with only the backbone is just a skeleton. It must have flesh and blood to be living physics."

"Then what is the flesh and blood of physics?" Wu Bin asked curiously.

"New things, living things, things closely related to phenomena. In the vernacular, we should pay more attention to the research frontier. In my eyes, now you are a physical person of flesh and blood."

Faced with this sudden high evaluation, Wu Bin was a little stunned.

Without giving Wu Bin a chance to reply, Yang Zhenning continued: "In your paper, I read the kind of innovative spirit that is not afraid of anything. You dare to make breakthroughs and are willing to make breakthroughs. You make drastic revisions based on previous research. I love that spirit.”

Wu Bin: "I am very happy to receive your recognition, Professor Yang."

"It's time to eat."

Hearing the sound coming from the kitchen, Yang Zhenning said to Wu Bin: "Let's eat first."

Wu Bin: "Okay."

However, for the two people who were chatting deeply, sitting down at the dinner table only changed the place where they were talking. After three hours, the topics they talked about had changed several times, but the rice in the bowls was almost unchanged. .

It wasn't until Weng Fan brought the reheated pork rib soup to the table for the third time that Yang Zhenning looked at Wu Bin with a smile and said, "Eat first, the taste will be really wrong if it is reheated."

"Okay." After hearing this, Wu Bin immediately moved his chopsticks and swept across the dining table. He did not forget to say a few words to Weng Fan: "Your craftsmanship is really good."