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

Chapter 676 Dissatisfaction
Li Yu cited the word "spin" for the first time in his paper, three or four years earlier than in history.

In the article, he explained that two points occurred in the Stern-Gerlach experiment because electrons have the innate intrinsic property of spin.

Future generations of high school students will understand. Those who have studied chemistry must know that the chemical properties of atoms are reflected by the outermost electrons. The spin has two values, 1/2 and -1/2, which are expressed as two points.

It's just that because the experiments conducted by Stern-Gerlach were not that complete, they were not explained in too much depth.

But between the lines, Li Yu has explicitly or implicitly proposed that the spin of an electron cannot have definite values ​​in two directions at the same time.

The word "spin" is a bit misleading. At first glance, it sounds like electrons are spinning, but this is not the case. Many people may have overlooked a phenomenon: elementary particles such as electrons have not measured a lower volume limit, and are more like a conceptual point. In other words, there is radius but no volume - it is indeed not easy to understand, but there are many things that are difficult to understand in quantum mechanics, so just know it first.

If it really has a size, if this thing spins, if you calculate it, the surface is far faster than the speed of light, which is definitely wrong.

Anyway, Li Yu officially put this experiment on the table, gave a theoretical explanation, and defined the intrinsic property of spin.

Of course, there are still many things worth exploring in the future, so I won’t bother Li Yu, Pauli and others will take action on their own.

This was a very important discovery in the quantum field. After Bohr saw the article, he immediately came to Berlin from Copenhagen.

Li Yu and Einstein picked him up at the station.

"Professor Bohr is busy at the Institute of Theoretical Physics in Copenhagen, so it is not easy to find time to come to Berlin." Einstein said.

Bohr said helplessly: "I am really too busy and can't even continue to do research. The purpose of my original application to build the Institute of Theoretical Physics was to do research."

"Not enough manpower?" Li Yu asked.

Bohr said: "It is true. There are four people in the entire institute including me, and there is only one scientific assistant responsible for scientific research. I applied to the Danish Ministry of Education, hoping to add an assistant, but unfortunately the Minister of Education rejected it."

Li Yu said: "I heard that Professor Rutherford sent you another letter of appointment, promising a laboratory and extremely high funding, and that you would not need to hold other jobs and devote yourself completely to scientific research. You did not agree?"

"I still want to stay in Copenhagen." Bohr said.

Li Yu smiled and said, "Then you can pretend that you accidentally let the Secretary of Education see the appointment letter and letter from Professor Rutherford. Maybe he will change his mind."

"What a great idea!" Bohr said happily, "I'm going to find a way to do it without leaving any trace."

Several people drove to Einstein's residence. Bohr put two boxes on the table: "You each have one. Inside are Danish specialties."

"Cookies?" Li Yu joked.

"No, the biscuits are better from France," Bohr opened the box, "they are cheese and butter from Denmark."

Einstein said: "Orientals do not seem to eat cheese and butter."

"It's okay to eat occasionally." Li Yu said.

Einstein called his wife Elsa: "Mr. Li Yu must eat the most authentic honey cheese with sausage. The beef liver we just bought today is also lightly fried in butter. It is absolutely delicious."

"I'm looking forward to it very much," Li Yu said.

Europeans have always eaten animal offal, and they eat more whole parts than most Chinese people. There are almost no parts that they don’t eat. In the past, people thought that Westerners did not eat animal offal because of the Chinese living in North America. It is true that Americans eat relatively less offal.

Bohr talked about the purpose of this visit: "Someone has proved that Mr. Maxwell's probability curve is correct and is very important to quantum theory, revealing the decisive position of probability and contingency in quantum theory. Now Mr. Li Yu even used The theory explains a magical experiment in which chance can also be seen at work."

Einstein said: "Professor Bohr thinks that physics should give up continuity and causality?"

Bohr firmly said: "I am convinced of this. In view of the current evidence, giving up strict certainty is the only way out."

"Although quantum theory has made great breakthroughs in atomic structure, and randomness has also impressed me a lot, I often feel worried," Einstein said with emotion. "Maybe I could have obtained it myself." A similar conclusion could be reached, but if so, it would be the end of physics."

Li Yu said: "The building has just been built now. I think randomness is the most critical, just like chaos in mathematics. There are many things that we cannot predict at all. Even slight disturbances will bring unpredictable consequences." Result. Mathematics is the queen of science and needs to be used to explain other sciences. Mathematics itself contains chaos, not to mention physics? "

"I agree with Mr. Li Yu," Bohr said. "For example, in the most basic photon radiation, we cannot determine in which direction a photon will be emitted, and we cannot determine when it will be emitted."

Li Yu added: “If an atom is in a higher energy state, the probability that it will emit a photon at a specific moment can be calculated, but no matter how much information you have, it is impossible to accurately determine the time and direction of the emission, just like throwing a dice. It’s all about chance.”

"Accidental?" Einstein said, "This threatens the strict determinism of Newtonian mechanics and destroys the deterministic belief of classical physics."

Bohr said: "As Li Yu mentioned just now, because of the existence of chaos, even if you know all the positions and speeds of a system, you cannot determine its future. There is no determinism in mathematics and physics."

This is one of the core ideas of quantum theory, but obviously Einstein's theory of relativity still retains strict causality, so he opposed quantum mechanics.

"Reducing physical processes to chance looks like irresponsible behavior in any case, and is a weakness of the theory," Einstein said. "If we think that the universe is essentially random and events can happen without reason, it not only makes us Deeply disturbed, as most physicists must have been, because randomness undermines the entire program of physics."

Li Yu said: "What if randomness makes the world so colorful?"

Einstein said: "I don't know, but I will not compromise on the point of causality. I will seek help from Göttingen. They may have other ways to explain the absorption and emission of light quanta."

Bohr said: "Professor Born of the University of Göttingen corresponded with me several times. We talked about the transition of electrons. He didn't seem to be opposed to randomness." "Even he compromised?" Einstein was a little desperate. "Does he actually think that an electron exposed to radiation can use its free will to choose not only the moment of transition but also its direction?!"

Bohr nodded: "Professor Born seems to have accepted it and is ready to study this issue."

Einstanton felt helpless, but he still insisted: "I think this kind of thinking is intolerable! If this were the case, I would rather be a cobbler, or even an employee in a casino, than a physicist."

"Casinos don't necessarily rely on randomness, Mr. Einstein," Li Yu said with a smile, "You must not have played cards a few times."

Bohr also laughed: "It seems that my cheese and butter cannot bribe Professor Einstein."

Elsa happened to come over with fried beef liver and sausages: "You can bring more next time. Einstein likes it very much. Maybe it can make him change."

"I'm afraid it won't be easy." Li Yu said.

Throughout his life, Einstein resisted the dominance of probability and uncertainty over nature in the realm of quantum mechanics.

Although there were many anti-relativists at this time, they misinterpreted Einstein's theory of relativity as the end of certainty and absoluteness in nature. But in fact, Einstein didn't think so.

Einstein believed that the theory of relativity derived a higher level of certainty, that is, a deeper description of certainty and absoluteness based on the four-dimensional space-time structure, which he himself called "invariance."

That’s why Einstein was so opposed to the uncertainty of quantum theory, and even this opposition has risen to a philosophical level.

But no matter what, Einstein still won this year's Nobel Prize in Physics. The official letter sent by the Royal Swedish Academy of Sciences specifically stated: "In recognition of Mr. Einstein's contribution to theoretical physics, especially because He discovered the law of the photoelectric effect."

Not long after, a letter from the Nobel Prize jury stated more bluntly: "The award of this prize does not take into account the value that your theory of relativity and gravitational field theory will have after they are confirmed in the future."

Because it was dark humor for Einstein to win the photoelectric effect. This research was first based on some of the results of his archenemy Leonard many years ago.

After Leonard learned that Einstein had won the award, he was extremely angry and angrily wrote a letter to the Royal Swedish Academy of Sciences, claiming that "Einstein misunderstood the true nature of light, and he was also a Jew pursuing fame and fortune." , its approach runs counter to the true spirit of German physics.”

This is the only formal letter of protest received by the Royal Swedish Academy of Sciences, but the result has been made and the award will definitely be awarded.

Li Yu was invited to attend the award ceremony. At Stockholm City Hall, Li Yu met chemistry prize winner Sodi and his mentor Rutherford.

Soddy is a member of Rutherford's "Nobel Prize Kindergarten".

After meeting Li Yu, Sodi said with excitement: "It was the article about the isotope hypothesis by Mr. Academician that made me embark on the path of research on isotopes. I am able to win this award because of your contribution." ”

Li Yu smiled and said: "What's so difficult about coming up with a hypothesis?"

Rutherford said: "You are not just making random assumptions. Sometimes when we discuss in private, we all feel that you are a scientific astrologer or prophet, and every word you say is very accurate."

In the Chemistry Prize award speech, Sodi thanked Li Yu and Rutherford in his speech: "First of all, I am very grateful to the Nobel Committee for recognizing me. At tonight's award ceremony, I can share this moment with you. , I am deeply honored, because sitting in the audience are two sages who are crucial to my career, Professor Li Yu and Professor Rutherford. I would like to quote a proverb from Mr. Li Yu’s hometown, no one has planted it. If there are no trees, there will be no shade for future generations to enjoy!”

The crowd immediately burst into warm applause.

Rutherford said to Li Yu: "He has also read the collection of Chinese proverbs and idioms written by a scholar named Gu Hongming in your country."

Li Yu smiled and said: "It's a good quote."

When the physics prize was awarded, Arrhenius, chairman of the Nobel Prize Committee, first delivered a speech: "This year's Nobel Prize in Physics is awarded to Mr. Albert Einstein. As we all know, in addition to Mr. Li Yu just mentioned, perhaps No other living physicist is as famous as Albert Einstein, and much of the discussion centers on his theory of relativity.”

Arrhenius changed the subject and said in an almost contemptuous tone: "It is essentially epistemological, so it has always been a hot topic of debate in philosophical circles."

Then he briefly introduced Einstein's work as usual, and then gave the Academy of Sciences' explanation for his award: "Einstein's photoelectric effect law has been tested by Millikan and his students in the United States with extremely rigorous methods. And passed the test with flying colors. Just as Faraday's law is the basis of electrochemistry, Einstein's law has become the basis of quantitative photochemistry. Because, the committee decided to award the award to Mr. Einstein in recognition of his work on the photoelectric effect. of outstanding results.”

The photoelectric effect can also be considered as content in the quantum field, which Einstein was opposed to in the latter half of his life.

The Millikan experiment mentioned by Arrhenius was originally conducted to find evidence against Einstein.

This series of coincidences is quite funny.

But everyone actually knows that in the face of the theory of relativity, the photoelectric effect can only be said to be a relatively common task. Einstein became famous because of his theory of relativity, and even had observational evidence of solar eclipses. The Nobel Prize jury will definitely award him the award. As for the reason for awarding the award, you can just find any reason.

Einstein had no dissatisfaction with Arrhenius's speech. In his speech, he almost exclusively talked about the theory of relativity rather than the photoelectric effect. And at the end he emphasized the importance of his new work, namely the unified field theory.

This actually made many listeners feel very excited. Everyone has long wanted to integrate weird quantum theory into classical physics.

At this time, the Swedish krona was quite valuable. Sweden was not affected much by World War I. Instead, it made a lot of money and became extremely rich.

The bonus Einstein received was 121572 Swedish krona, approximately US$32000, which is more than ten times higher than the annual salary of an average university professor.

In this period of crazy depreciation of the German mark, there is no doubt that it is a huge amount of money.

However, according to the divorce agreement with his ex-wife Mileva, Einstein had to send half of the money directly to her.

The two seemed to have also discussed some financial planning, and Mileva used the money to buy three apartments in Zurich for rent.