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

Chapter 673 Wall of Sighs
Eddington entered the room late, holding a telegram from the United States, saying: "I heard a very puzzling result. It seems that someone has improved the techniques of the Michelson-Morley experiment and claimed to be able to prove the aether." Yes, the speed of light is variable.”

Li Yu knew it was impossible, so he said: "This kind of information source sounds unreliable and needs to be explored again."

Einstein also felt a little weird and said: "It seems that just after I became an authority, someone wanted to overthrow me."

Li Yu smiled and said: "They have to overthrow Michelson first."

Eddington said: "There are too many people who want to be famous nowadays, and there is always someone who is going to come up with some shocking conclusion."

Einstein said calmly: "God is elusive, but he is not malicious."

This is a famous quote by Einstein that was later engraved on the fireplace in the lounge of a Princeton University mathematics building.

Einstein's explanation for this was: "Nature, because of her noble nature, hides her secrets, but not through trickery."

However, in more than ten years, when quantum mechanics became more and more perfect, especially when the uncertainty principle, one of the core theories, and the probabilistic interpretation of the wave function appeared, the situation was completely different. In his later years, Einstein once stood there. In front of the fireplace, lamented: "Who knows? Maybe he does have a bit of malice."

Eddington said: "I have sent a telegram to Professor Michelson to inquire."

"He's still measuring the speed of light as usual?" Einstein asked.

"Yes," Li Yu said. He often goes to the United States and has a better understanding of the American physics community. "Professor Michelson built a 22-mile optical path in California and wants to make more precise measurements."

"It's incredible!" Einstein said, "Professor Michelson can be called an artist in science."

"In any case, it is impossible to measure changes in the speed of light. People who say these things should check their own experimental instruments and experimental principles, or go to Professor Michelson to have a look, instead of immediately throwing out irresponsible conclusions. , this behavior itself is not scientific at all," Li Yu said.

Eddington has always been a supporter of the theory of relativity and said: "The affirmation of these two gentlemen is the best cornerstone for the new building of physics."

Li Yu joked: "I don't want to be stepped on so early."

"Mr. Li Yu really knows humor." Einstein also laughed.

Eddington added: "In addition, Mr. Einstein, I would like to apologize to you. The Royal Astronomical Society was originally going to award you a gold medal, but due to the opposition of some chauvinistic British defenders, the award was canceled. Forced to cancel.”

Einstein was unimpressed: "Compared with your fruitful efforts in the theory of relativity and its confirmation, the bittersweet results of the award event are not important at all."

"Thank you for your detachment," Eddington said.

Einstein was indeed a very transcendent person, which was in line with the independent feeling of a great scientist.

-

After a few days in England, they returned to Europe together, with their first stop being Paris.

While sailing on the sea, the two drank coffee together on the covered bridge. Einstein put a few tablespoons of coffee powder in the cup and kept stirring it.

"Do you like drinking such strong coffee?" Li Yu asked.

"If it's too light, it won't taste good." Einstein took a sip and said, "Don't the Chinese also have the habit of drinking strong tea?"

"At least I'm not used to it." Li Yu said.

After drinking the coffee, Einstein lit another cigar. The smell was a bit pungent, and it did not seem to be a high-end Cuban product.

"It's so pleasant to smoke a cigar on the boat and look at the sea water. This way I can think about many problems." Einstein said.

His second wife Elsa said: "I really hope you can think about the problems in life and not always be so slovenly."

Einstein blew out smoke: "If I think about these questions, what are you thinking about? It will bring your brain to a standstill."

"Thank you for your concern!" Elsa said.

Li Yu asked casually: "Madam, do you understand the theory of relativity?"

"Me?" Elsa shook her head, "I don't need to understand, because it doesn't matter whether I understand it or not."

She is obviously nothing like Einstein's first wife and is more concerned about life.

As they continued to chat leisurely, a young man suddenly recognized Einstein and Li Yu: "Oh, my God, both of them are here, great!"

Einstein said somewhat helplessly: "Sure enough, it was discovered."

The young man couldn't wait to come over with a manuscript: "Mr. Einstein, I have a very great discovery, which comes from your mass-energy equation. Since mass and energy can be converted, and the energy obtained by substituting into the formula is so huge, then You can use the energy contained in atoms to create powerful explosives!”

Einstein said: "I don't quite agree with your idea. My formula is just a purely physical theory. How can it involve explosives!"

Seeing that Einstein refused to continue the discussion, the young man said to Li Yu: "Mr. Li Yu, who comes from the mysterious East, you also understand the theory of relativity. Isn't what I said right?"

Li Yu smiled and said: "Your idea is very dangerous, and tell me, is there any way to release this energy? If you just think about it briefly, any substance, including a piece of sugar, is a hidden bomb. ?”

The young man was stunned and couldn't answer.

It can be seen that his physics foundation is not very solid, and he knows very little about atomic physics.

The young man left angrily.

Einstein said: "It cannot be that any scientific progress will eventually be linked to weapons that kill people!"

Li Yu said: "From the perspective of human development, it seems that this is really the case."

Einstein said speechlessly: "Then I would rather be an ordinary lecturer. In my spare time, I only study astronomy and mathematics that are harmless to humans and animals."

"I'm afraid these areas won't be able to take advantage of your thought experiments," Li Yu said.

"No, for example..." Einstein thought for a moment, "for example, use your chaos theory to discuss the solar system. By the way, didn't some people say that Jupiter might be a failed star? Just imagine that it turns into a red star. Dwarf stars, it’s so interesting to see what the solar system will look like.”

"You can think of it," Li Yu said with a smile, "but Jupiter is too small. If it wants to become the smallest red dwarf star, its mass must be increased by at least 80 times, which means it must reach 0.1 times the mass of the sun."

Einstein was a little interested: "80 times? The volume must be much larger?" Li Yu said: "No, because even the smallest red dwarf star has great internal gravity, pressure and density, so the overall radius may be only It’s just an increase of % or %.”

"Gravity, pressure, density... There are only a few people in the world who can talk about relativity and quantum theory in one sentence at the same time." Einstein liked chatting with Li Yu, mainly because he liked thought experiments.

Li Yu said: "I have always believed that the next development of astronomy can only be more closely related to physics. The previous solar eclipse proved that the deflection of light is an example related to the theory of relativity, and the future development of cosmology requires atomic physics even more. ”

"I very much agree with your statement," Einstein agreed, "but it will be much more difficult to study astronomy in college in the future. Because for students studying astronomy, there is no longer only the big sun of mathematics. There’s also a little sun like Jupiter.”

"Far more than a small sun! Although this small red dwarf with 0.1 times the mass of the sun will emit heat like a star, it is too weak and not even as bright as the full moon. The energy it radiates is only about 0.02 watts, which is only stronger than the moonlight radiation. Only five or six times, the temperature of the earth will not be greatly affected."

"So, at least it should be a metaphor of two big suns," Einstein said with a smile. "If there is one more, it becomes a three-body system, which is even harder to say."

Li Yu said: "According to the current development of astronomy and physics, there are more than three suns."

"Oh? This brings me to a research direction that I am interested in." Einstein put down his cigar. "I am looking for a way to make physics less chaotic, at least without the situation of three suns running on their own. "

Li Yu knew exactly what he wanted to say, so he asked: "Do you want to unify the theory of relativity and quantum theory?"

"Don't you think that would be wonderful?" Einstein said excitedly. "I want to seek a mathematically unified field theory. In this theory, the gravitational field and the electromagnetic field are simply explained as the components of the same field. Different weights or manifestations.”

This is the "grand unified theory" that Einstein has been striving for for the rest of his life.

It should be noted that at this time physicists had only discovered two forces: gravity and electromagnetism.

Gravity can be described by general relativity.

Electromagnetic force can be described by Maxwell's equations in classical physics; in the quantum field it can be described by quantum theory.

So to put it simply, Einstein wanted to unify gravity and electromagnetism.

However, as a time traveler, Li Yu knew that Einstein was going in the wrong direction.

Later generations of scientists have also been working on grand unified theories. After all, the theory of relativity and quantum mechanics do have many problems that are difficult to reconcile. The most troublesome thing is that both are right.

But if we want to achieve great unification, gravity must be the last one to be included.

Before Li Yu traveled through time, scientists had unified the electromagnetic force, the strong force, and the weak force. The process during this period was very complicated, and the theory was extremely difficult, and it was even difficult to popularize it.

To put it simply, at least we have to wait for Yang Chenning’s Yang-Mills gauge field theory to come out, so that we can slowly unify the weak force; then quantum chromodynamics will appear, and then we can unify the strong force.

Therefore, many people used to wonder why Yang Zhenning could be compared with Dirac, but felt that his fame could not be compared with that of Hawking. It was because the things Yang Zhenning did were too complicated and could only be exposed to pure physics majors. There was almost no way to popularize science. Let’s briefly talk about the importance.

One more thing, the standard particle model created and continuously improved by Dirac does not include gravity...

In short, you can imagine what a difficult path Einstein chose - basically a "wall of sighs" in front of him.

But Einstein could not know this, and he still said enthusiastically: "I chatted with Professor Planck a few months ago, hoping that he can participate in unifying quantum mechanics, electrodynamics and Newtonian mechanics into a logical system. Come in research.”

"What did Professor Planck say?" Li Yu asked.

"He said he was somewhat interested, but he didn't have the time," Einstein replied. "After all, his time is too short, and at that age, it is really not the time to engage in scientific research. Mr. Li Yu, you are also a rare person in physics. Scientists who are very knowledgeable in science and mathematics, do you want to participate in my unified theory?”

Li Yu didn't know how to refuse, so he asked: "Why are you so sure that they can be unified together?"

Einstein said: "Because I found that several mathematicians have put forward very constructive results."

He immediately told Li Yu about his recent discoveries.

The reason why Einstein was obsessed with grand unified theory can be attributed to this series of "mistakes", that is, his wrong reactions to some mathematical results.

For example, a mathematician named Kaluza proposed two years ago that a fifth dimension, a cylindrical dimension, could be added to Einstein's four-dimensional space-time theory. If you walk in one direction, you will return to the origin.

Mathematically, you can add a few more dimensions, but the key is how to find a physical explanation.

After Kaluza showed his paper to Einstein, Einstein admired it very much. He had changed from not paying attention to mathematics in the past to attaching great importance to mathematics, even a little more than physics.

But if you look at Einstein's general relativity equation, you will know that it is a terrifying differential equation containing 10 components; and five-dimensional space-time will add 5 more components, which will be extremely difficult mathematically.

However, this angle cannot be wrong. Later string theory has been developed to 11 dimensions.

(But string theory and Kaluza’s approach are different.

String theory was discovered in the 1960s when a mathematician accidentally constructed a function, which can be used to describe some scattering conditions in the strong force process.

Then everyone discovered that the great god Euler had studied it more than 200 years ago and gave this function.

It can be said that the mathematician has found a treasure. The most amazing thing about Euler's function is that in the function, particles can be regarded as a certain extension of space, in other words, a kind of string.

There are really traces of Euler everywhere...)
Talking back to Einstein's experience, he also met another mathematician who gave some results to explain the extra dimensions, and by the way, could explain the so-called "hidden variables" in quantum mechanics.

Einstein was also very concerned about this result, mainly because he had now begun to oppose quantum mechanics. In his view, the reason why quantum mechanics has uncertainty and probability theory is only because there are "hidden variables" that have not been discovered by humans.

——Another big pit! Because later Bell's inequality experiments proved that "hidden variables" do not exist.

All in all, these are more mathematical perspectives. Einstein went further and further down the road of mathematics, ignoring physical explanations for a while.

It was all because mathematics was too important to his theory of relativity before, causing Einstein to overcorrect.

Since then, Einstein has proposed the "grand unification" theory several times, and the media has also vigorously exaggerated it, but without exception it has been proven to be unsuccessful.

Li Yu took his time and said: "Although I understand general relativity, studying the unification of general relativity and quantum mechanics is not my direction."

Einstein had some regrets: "Perhaps you will change your mind in a few years."

Li Yu smiled and said, "You don't have to be too persistent."

It was impossible for Einstein to give up his research on the grand unified theory with just a simple persuasion.