From Almighty Scholar to Chief Scientist

"Well, I feel that this equivalent topological structure will have very little resistance to electrons."

Chen Xun: "... Can you feel this too?"

As a professor of physics at Peking University, I don't read much, so don't lie to me.

The critical current density of a superconductor, how can you feel whether it has become larger or smaller?

This is simply out of line!

Lin Xiao shrugged and said, "You build a microscopic structure of yttrium barium copper oxide in your mind, and then simulate its electrons, and then deduce the effect of electron flow after pressurization, and you can feel it."

Chen Xun: "..."

He silently tried it in his mind, but there are more than ten molecules in a yttrium barium copper oxide unit cell to form a conductor, at least a few more unit cells should be made?

In that way, the amount of calculations in the brain will increase.

So in the end, Chen Xun chose to give up, and then complained: "My head is a human brain, not a computer."

Lin Xiao couldn't help shaking his head and laughing, obviously Chen Xun was complaining that his head was like a computer.

But this may be true. At least, Lin Xiao now feels that his brain is like a computer, and it is multi-core and multi-threaded, because he has been able to do five things at once.

He even felt that if he did more training, it might be possible to concentrate on all tasks. Of course, the problem of thinking should not be too complicated, but things like building molecular structure models and simulating electron flow directly in his mind , is still quite possible.

However, he didn't bother with this issue, and then said: "Okay, in fact, this is not a key issue."

"Key question?" Chen Xun looked puzzled.

"You said, what determines the critical current density?"

"Maximum Carrier Throughput."

"Well, the BCS theory told us that the carriers in low-temperature superconductors are Cooper pairs, so what about high-temperature superconductors?"

Chen Xun shook his head, "I can't say anything about that."

After all, this is also a point of debate in academic circles.

Lin Xiao smiled mysteriously, without explaining, but said: "First apply for the patent of this new type of yttrium-barium-copper-oxygen. During this time, I will write a thesis."

Although there are still some doubts, but after Lin Xiao said so, Chen Xun nodded and said, "I'll go to them to apply."

This kind of superconducting material with an improved critical current density must be patented.

Chen Xun took a look at the current that Lin Xiao had tested so far, and it even reached [-] amperes. Such a current has reached the level of niobium-titanium alloy.

As long as you apply for a patent, you will definitely be able to make some money in the future. Although it cannot be made into a flexible wire, it can still be used.

As for the thesis that Lin Xiao was going to write, it was probably about the properties of this new structure, YBCO, so Chen Xun didn't ask any more questions, and then left the laboratory.

But Lin Xiao continued to look at the yttrium-barium-copper-oxygen alloy in front of him, thinking in his heart.

He calculated it at the Institute of Physics more than a month ago. The reason why the critical current density of the transformed yttrium barium copper oxide can be increased is because more electron pairs suspected to be Cooper pairs appear.

However, he is still not sure whether these electron pairs are true Cooper pairs.

This made him start to diverge his thinking.

"First of all, why can it be superconducting under high pressure?"

On October 2020, 10, several scientists in the United States used extremely sophisticated experimental equipment to achieve superconductivity at 15 degrees Celsius at a temperature of 267Gpa.

The superconducting material they use is carbon-containing hydrogen sulfide.

But something like hydrogen sulfide is a gas at room temperature. How does a gas test superconductivity?

This is because the pressure of 267Gpa is equivalent to exerting a gravity of 26.7 tons on one square millimeter, and then directly compressing the gas into a solid.

There is obviously no difference between becoming a solid and solidifying at a low temperature, so high-voltage superconductivity and low-temperature superconductivity are essentially the same.

So Lin Xiao quickly passed this idea in his mind.

But then, his eyes suddenly flashed.

"By the way! Landau's Fermi liquid theory!"

"In the current academic circle, the understanding of strongly correlated physics beyond the framework of Landau's Fermi liquid theory is still at the stage of scratches."

"The mechanism of high-temperature superconductivity must be the strong correlation between electrons and fermions."

"According to the framework of Landau theory, as long as the perturbation theory converges, the interacting fermion system will behave qualitatively consistent with the non-interacting system..."

"If you substitute the situation of yttrium barium copper oxide into it..."

In Lin Xiao's brain, countless inspirations emerged like an explosion.

But all these inspirations eventually converge on one question.

"The perturbative divergence is not accompanied by a spontaneous symmetry breaking, but instead forms a highly correlated quantum liquid state—a non-Fermi liquid state."

"So, what is a non-Fermi liquid?"

Lin Xiao frowned, recalling all the documents and theories he had read.

"The current academic community only clarifies what is a Fermi liquid, but it only explains what a non-Fermi liquid is, and any Fermion model that is not a Fermi liquid is a non-Fermi liquid. What is it specifically? It's still foggy..."

Lin Xiao suddenly had a feeling that the high-temperature superconducting mechanism was hidden between the similarities and differences between the non-Fermi liquid and the Fermi liquid.

He scratched his head, and the feeling came again.

The more you pursue why, the more you enter into deeper problems, and this often means more and more trouble.

But he had to continue.

Sighing helplessly, he suddenly asked in his heart: "System, how many truth points do we need to exchange for that room temperature superconductor?"

System: "485 truth points are needed."

It is equivalent to saying that I have only completed 15 truth points of work after more than a month of hard work.

"Well, it's at least 3% progress, keep going."

As long as it takes another 33.33 times more than a month, he will have spent 500 truth points for nothing.

Well, thinking about it this way, I really didn't lose anything.

After comforting himself, he returned to his office and decided to finish the thesis first. As for Landau's Fermi liquid theory, let's wait until he has published the thesis.

……

In this way, time passed quietly again.

The days have come to the end of December, entering the academic world at the end of the year, but there is no change at all. At most, most Westerners temporarily put down their jobs and start celebrating Christmas.

However, two top international journals, "Nature" and "Physical Review Letters", successively published their last articles of this year, and they each had two articles, which caused a shock in the superconducting world.

"In the superconducting process of yttrium barium copper oxide, is it still because of a suspected Cooper pair of electrons that plays a role?"

This theory, which shocked superconducting physicists, appeared in front of them without any precautions or concerns.

Then, these superconducting physicists stopped thinking about taking a break at the end of the year, rushed into the laboratory, and started their experiments.

3 Chapter [-] The unity of linearity and nonlinearity?

"This question, you first do this..., then this..., then this..., and finally this..., did you come out?"

At Beijing University, in Lin Xiao's office, he was explaining the topic to Li Min.

After listening to Lin Xiao's narration, Li Min nodded thoughtfully, "I see."

"Well, if you study this content, the main thing is to continue to expand your knowledge... By the way, the book I told you about last time is Jurgen Neukirch's Algebraic Number Theory, have you read it? ?”

"This...uh, I have read it, but it's a bit difficult."

Li Min had a helpless expression on his face.

Lin Xiao smiled and said: "It's normal to study mathematics, but if you encounter a problem, what you have to do is try to start with this problem. You can check the literature, but I hope you check the literature to verify your answer. , rather than looking for answers for the sake of answers, unless you really can't find a solution."

"I see."

Li Min nodded, indicating that he understood.

However, he asked curiously: "Professor, what if you encounter a problem that you really can't solve? What will you do?"

Hearing this question, Lin Xiao frowned slightly and fell into thinking.

For a while, he didn't answer. Li Min was a little puzzled, but just when he was about to ask, Lin Xiao gave the answer: "For the time being, I haven't encountered any problem that I can't solve, so I may return it to you." You can't answer."

"Ah this..."

Li Min was stunned.

Lin Xiaoxing may feel that it is a bit too shocking, so he smiled and waved his hands, explaining: "Of course, maybe if I try to solve it now...such as the Riemann conjecture, P=NP, or Navier-Stowe The existence and smoothness of the solutions to the Kekes equation, I probably can't really solve it."

Li Min: "..."

I thank you for your comfort.

According to what Lin Xiao said, isn't it possible that only this kind of world-level math problem can stump him?

It's not even certain to say that, after all, Lin Xiao solved Hodge's conjecture at the beginning.

What if Lin Xiao really starts researching and solves it directly?

Thinking of this, Li Min turned around and said, "Professor Lin, my admiration for you is like a torrent of water..."

The instructor is so awesome, what else can he do?Of course it's licking!

What's wrong with licking your own mentor?

No problem at all!

However, just as he was about to start licking, there was a sudden knock on the door.

"Please come in."

Hearing the knock on the door, Lin Xiao spoke.

The door opened and several people came in.

I saw six or seven professors running in from outside, all from the School of Physics, including Chen Xun, who Lin Xiao dug into the Dingguang Research Institute.

These professors ran in, rushed up and surrounded Lin Xiao, and then hurriedly said: "High-temperature superconductivity, is it also because of the electron pair? Or is it the Cooper pair?"

When Li Min saw several professors, he quickly stepped aside and looked puzzled.

What are these professors looking for Professor Lin for?

What high temperature superconductivity?

But Lin Xiao couldn't help being taken aback when he saw so many people running in suddenly: "Where is this, everyone?"

"It's the article you published in Physical Review Letters!"

Chen Xun said directly, "I talked to you about your new yttrium-barium-copper-oxygen. At that time, I was still wondering why there was such a change, but I didn't expect how long it had passed, so I just figured out why. Already!"

Lin Xiao said with a smile: "Didn't you say that at the beginning, the increase in the critical current density means that the number of carriers has increased. What are the carriers in the material? It must be electrons, and then this is very difficult. Do you understand?"

"This……"

Chen Xun was taken aback for a moment, and then complained: "But who knows that it will be an electronic pair, and it may even be a Cooper pair!"

"I didn't say it was a Cooper pair, it is still an electron pair, but according to the mathematical expression, it is a bit like a Cooper pair." Lin Xiao said.

These superconducting physicists who ran over looked at each other, listening to what you said, as if listening to a word.

Another professor next to him asked, "Professor Lin, what do you think it would be if it wasn't a Cooper pair? A brand new electronic pair?"

Lin Xiao shook his head: "That's not sure."

Then he said: "In low-temperature superconductors, Cooper pairs form because there is an arbitrarily small attractive force between electrons that causes electrons with energies below the Fermi energy to pair with each other."

"But obviously, the Fermi energy is very low, and it only takes a little bit of temperature, and the thermal energy of the electron is enough to make its energy exceed the Fermi energy."

"And our yttrium barium copper oxide can maintain a superconducting state at a temperature of up to 90K. In fact, I would rather believe that it is a brand new electron pair form, and the Cooper pair is just a type of this new electron pair. Special case."

Several professors were taken aback.

Another professor asked the question: "Why? Why can't there be two cases? The Cooper pair is the case at low temperature, and this brand new electron pair is the new case at high temperature?"

They were all a little puzzled about Lin Xiao's point. Why do they have to think that the two situations are the same?

Can't discuss by category?

Quantum mechanics has said that the world is discontinuous, and it is completely normal to discuss it in two cases at high temperature and low temperature.