A Man of Science and Engineering in Troubled Times Wandering in the Late Qing Dynasty

Chapter 711 Epilogue : Continue to Create God
Li Yu's personal focus is now completely on education.

After meeting Sun Xuewu and Fu Sinian, they both had solemn expressions.

"The Japanese are such bastards!" Fu Sinian said hatefully.

"Not even as good as a bastard!" Li Yu said coldly.

"You two, walls have ears, please keep your voice down!" Sun Xuewu reminded them.

Li Yu calmed down and took out a document: "This is the instruction from the Ministry of Education. They have decided to move the university to Qingdao."

Fu Sinian said: "Qingdao? Aren't there more Japanese there?"

"Qingdao has more resources after all, and with the current situation in Jinan, how do you think we can go to school?" Sun Xuewu sighed, "There are many foreigners in Qingdao, including British and American military attachés. The Japanese at least don't dare to be so presumptuous."

"It's good to relocate the school, and we can reorganize it," Fu Sinian said. "The former devil Zhang Zongchang actually wanted to be the principal himself, which was ridiculous! What kind of culture did Zhang Zongchang have? It's ridiculous! Do you want all the students in Jinan to recite his "Daming Lake"?"

Li Yu was also speechless when he thought of Zhang Zongchang, the "weird poet". "Daming Lake" was a doggerel poem:

Daming Lake Daming Lake
There are lotus flowers in Daming Lake

Toads on the lotus

One poke and one jump
But you know what, even so, Zhang Zongchang's poems are more popular than Qianlong's...

Li Yu said: "I have no objection to the choice of the school site. In addition, in addition to the part of the Boxer Indemnity that has been agreed upon, I will provide more funds to help run the school."

Fu Sinian said happily: "Thank you, sir!"

Li Yu added: "There are quite a few Germans in Qingdao. I will contact them and ask them to send a group of teachers here."

Anyway, Germany will become anti-Semitic in the future, so there are plenty of people to use.

It would be a waste if you don't pick up such a good deal.

-

In addition to these basic educational tasks, there is one more important thing: to create a few more scientific "gods". In the Republic of China, an era of serious lack of self-confidence, adding a few more gods will have a very obvious effect.

The first person to be built was Zhao Zhongyao, who was close to a "miracle".

Although his matter was not difficult to handle, Li Yu had to go there in person.

After arriving in the United States, Li Yu immediately went to California Institute of Technology and found Zhao Zhongyao.

Zhao Zhongyao was a little disappointed at this time, but his expression changed when he saw Li Yu: "Mr. Academician!"

Li Yu asked directly: "Is the experiment completed?"

"It's done," Zhao Zhongyao said, "but..."

"But what..."

"The experimental results are somewhat strange," Zhao Zhongyao said. "The absorption of hard gamma rays when passing through light elements is consistent with the Klein-Nishina formula. However, when gamma rays pass through heavy elements, anomalous absorption occurs, and the actual absorption amount is much larger than the predicted value obtained by the Klein-Nishina formula. For example, the measured value of lead is about 40% larger than the value given by the formula, which is very abnormal."

"There must be something wrong when things are abnormal," Li Yu said with a smile, "but in science, there might be something new, just like the abnormal Zeeman phenomenon at that time. So this experimental paper should be published as soon as possible."

"I guess there are some new things, but Professor Millikan thinks the gap between the experiment and the theoretical expectations is too large and he refuses to sign and publish the paper," Millikan said distressedly.

According to the tradition in the scientific community at that time, papers written by students or members of the public generally had to be signed by a university professor before they could be published, which was actually equivalent to a preliminary review.

This is what Li Yu came to do: "I'll go and persuade him."

Millikan was a relatively conservative scientist, or in other words, he was a person who only believed in experiments and was not very positive about unknown things.

The reason he was able to win the Nobel Prize was mainly because he was very good at experiments. Of course, doing experiments well is good enough to win the Nobel Prize. Many Nobel Prizes are won by the person who proposed the theory, and then by someone else who did the experiment. After all, these experiments are really difficult to do.

Li Yu placed Zhao Zhongyao's paper in front of Millikan and asked, "Professor, why is this paper not signed?"

Millikan took one look and said, "Zhao's experimental results are too outrageous! If we make a mistake, it will damage the reputation of Dr. Zhao Zhongyao and me."

What he said seems to make some sense.

But Li Yu would not speak without evidence, and immediately showed him evidence, showing another paper: "This is the equation of Dr. Dirac from the UK."

"Another equation?" Millikan frowned. He didn't pay much attention to the progress in theoretical physics, so he said, "I asked Professor Compton, and he said that you didn't reach a conclusion in several conferences, including the Solvay Conference. It's a waste of time to focus on these now, because no one knows whether it is right or not."

Li Yu said: "Dirac's equation fixed many defects and has now been recognized by the European academic circle."

"Is that so?" Millikan asked. "What did the paper say?"

Li Yu said: "Dirac solved the equation and found four sets of solutions, two about electron spin and two about electron energy. The first two sets of solutions are easy to understand, and the latter two sets show that the energy of electrons can be positive or negative."

"Negative energy?" Millikan understood the key point. "Shouldn't such a solution be discarded?"

"Dirac's equation has symmetry, which obviously cannot be abandoned," Li Yu said, "and in another paper, he made a hypothesis called the 'Dirac Sea'."

Millikan felt even more confused after hearing this: "What is Dirac's sea? You people who study theoretical physics always like to create new terms."

Li Yu explained: "According to Dirac, the vacuum is not empty, but filled with negative energy orbitals, but we cannot see them. If the energy of the radiation is large enough, it can excite an electron from the negative energy orbital, that is, the vacuum. In this way, a hole is left in the vacuum, and this hole naturally carries a positive charge."

"That's a good idea!" Millikan said, but since there is a theory to back it up, it means that the experimental results make some sense. "Okay, I'll sign this paper and publish it." If there was no intervention in advance, Millikan would have suppressed Zhao Zhongyao's paper for more than three months before he agreed to sign it. At that time, a team in Europe also found similar experimental results.

With the timestamp of paper publication, the most important step has been completed, but it is not enough.

Dirac needs to make corrections quickly.

Based on his Dirac Sea model, Dirac currently believes that this positively charged hole should be a proton, because in current theory, only protons carry positive charge.

In addition, Dirac believed that since negative energy levels of electrons exist, then theoretically any electron can jump to this energy level - as long as it radiates photons outward.

When all the electrons in the universe become negative energy states, it will be terrible. According to Dirac's calculations in the paper, if this happens, the universe should be destroyed within one billionth of a second.

So the Dirac sea is not a very good model either. (In a few years, it will be replaced by quantum field theory.)
Li Yu then wrote a letter to Dirac, discussing the solution to the negative energy state and attaching some calculation results. He then wrote: "From a mathematical point of view, the mass of the hole must be the same as the mass of the electron, so it should not be a proton with a mass difference of three orders of magnitude. And I have calculated that the annihilation time of the two is also very different."

After receiving the letter, Dirac studied it for two days before replying: "If it wasn't a proton, we should have observed this strange new particle in the experiment. But a positively charged electron is too outrageous! Today's physics has formed a perfect structure, and it can even be said that the essence of the world has been explored.

"Photons make up electromagnetic waves, and protons, electrons, and the neutrons you predicted make up matter. With such a perfect theoretical framework, there is no need for outsiders. I think physics should be completed in about six years."

Well, following Lord Kelvin’s two dark clouds, Dirac also declared that physics was over.

Another flag.

Li Yu could only continue to reply: "You are also good at mathematics, and your own equation has symmetry. In this case, a positively charged electron is not difficult to accept."

In fact, Dirac did not dare to predict new particles. It should be said that the entire physics community is extremely cautious about predicting new particles.

If I do this, I will definitely be laughed at by Pauli, the "God of Argument".

But now that Li Yu was so sure, Dirac felt that it was not that simple, so after careful consideration, he published a paper, formally revised his paper, and proposed that the negative energy electrons predicted by the equation did exist, which he called "anti-electrons."

As expected, this article was ruthlessly attacked by the great Pauli... Other physicists were not very sure about this and did not express their opinions immediately.

Li Yu wrote an article and published it in "SCIENCE", and showed both of them to Zhao Zhongyao.

If it weren't for Li Yu, Zhao Zhongyao would have never seen these papers.

"Positron?!" Zhao Zhongyao was indeed surprised.

Li Yu said: "Dirac's paper called it an anti-electron, but I think it sounds better to call it a positron."

Zhao Zhongyao had been doing this experiment for a long time and had read a lot of literature. After thinking for a while, he said, "I have guessed that this special radiation is not caused by Compton scattering, but should originate from the nucleus. But considering that the intensity of the anomalous rays is almost uniform in different directions, it seems more likely to be caused by the secondary emission process."

The "anomalous absorption" discovered by Zhao Zhongyao can be simply explained as follows: in the measurement of the scattering of hard gamma rays by the heavy element lead, he found that in addition to Compton scattering, there was also a special kind of light radiation accompanying the anomalous absorption.

Zhao Zhongyao measured the intensity of this special radiation and found that it was roughly isotropic and that the energy of each photon was very close to the energy equivalent to the mass of an electron.

Li Yu said: "Combined with Mr. Dirac's paper, this result seems obvious. The so-called 'anomalous absorption' is actually due to the conversion of some gamma rays into positron-electron pairs around the nucleus; while the 'special radiation' is the annihilation radiation of the positron and the electron recombine and convert into two photons."

Zhao Zhongyao was even more surprised: "I didn't expect this to happen at all."

"So you should read more articles on theoretical physics!" Li Yu said with a smile, "Of course, the specific results still need to be calculated accurately, but I guess you have already calculated it. As long as it matches Dirac's prediction, you can officially announce the discovery of a new particle - the positron. It won't be long before you can also stand on the Nobel Prize podium!"

Zhao Zhongyao knew the value of this discovery and said excitedly: "I will write another article to discuss it right away!"

Historically, three people discovered the positron: the first was Zhao Zhongyao; then Blackett of the Cavendish Laboratory in the UK; and the other was Anderson.

Blackett even took hundreds of photos of positrons in the cloud chamber, but he never thought about positrons.

Interestingly, Dirac’s office building was right across from Blackett’s, but the two never discussed this issue.

The main reason is that Dirac was indeed a taciturn person, and his research was on a relatively niche field of theoretical physics at Cambridge University, which was different from the research direction of the Cavendish Laboratory.

As for Anderson, he was the one who won the Nobel Prize for discovering the positron. Anderson was also at Caltech at the time. He studied under Millikan and was a classmate of Zhao Zhongyao.

Anderson, like the other two, had not read Dirac's paper. He discovered the positron by accident while studying cosmic rays.

In other words, he did not have a direct purpose to discover the positron; it was completely accidental.

Looking at the achievements of these three people, each one was discovered by chance, but conversely, it was also a necessity in chance.

In addition, historically, Blackett later published an article citing Zhao Zhongyao's paper, but for some reason he wrote the wrong date of Zhao Zhongyao's paper, and claimed that the additional scattering of 0.5M electron volt energy discovered by Zhao Zhongyao had been calculated by many people. In fact, only Zhao Zhongyao himself got this result.

Due to the errors in Blackett's paper citations, the Nobel Prize Committee thought that Zhao Zhongyao's contribution was not that great and did not take it seriously.

Moreover, the September 18th Incident had already occurred in China at that time. Zhao Zhongyao was a very patriotic person, so he resolutely returned to China and was not very familiar with the situation in Europe and the United States.

Now with Li Yu's intervention, Zhao Zhongyao's new paper was published again. After confirming Dirac's prediction, it immediately confirmed the fact that the positron had been discovered. This Nobel Prize was set in stone and belonged to Zhao Zhongyao!

This result also made Dirac's equation more valued by the academic community, and his Nobel Prize was naturally more secure.

Millikan of Caltech was amazed and said to Li Yu: "When you mentioned that Zhao Zhongyao might achieve Nobel Prize-level results like Wu Youxun, I thought you were joking, but it turned out to be true!"

Li Yule said: "When did I ever say anything unreliable?"

Millikan said with emotion: "Now your country has four Nobel Prize winners, the same number as the United States. But if we count the number of awards, since Mr. Academician has won the Physics Prize twice, he has surpassed the United States in terms of number. It is unbelievable!"

The Americans currently have one chemistry award and three physics awards.

"It's not over yet." Li Yu said calmly.