Chapter 160 I found the problem

Xu You was so anxious to go to Wang Xiangwu's place because he was not just attracted by Wang Xiangwu's topic.

Indeed, during this period, there was no further progress on the subject of the mechanism of high-temperature superconductors.

Because this subject is so complex, breakthroughs at each small stage are even more difficult than solving an ordinary subject.

Xu You will often fall into a bottleneck state and find it difficult to continue to advance this topic.

It happened that Wang Xiangwu had another subject, and Xu You also felt that he could not put all his energy on a subject that was in a stalemate.

Moreover, as Wang Xiangwu said before, there are similarities between condensed matter physics and quantum physics.

Xu You indeed felt so.

Among the entire physics, condensed matter physics and quantum physics are indeed two closely related branches.

Maybe Xu You can really get some new ideas from Wang Xiangwu's laboratory.

After Xu You arrived at the quantum physics laboratory, Zhao Weijia greeted him immediately.

"Xu You! It's only through your light that I can appear on the central stage! You know, there are so many girls asking me on blind dates recently, and the queue is almost from Jida to Jinghua."

Xu You thought for a while, and it seemed that there weren't that many people there.

"So, senior brother, so many days have passed and you are still on a blind date?"

Hearing Xu You's words, Zhao Weijia smiled awkwardly.

"Dating is like picking fruits in an orchard. It is stipulated that you can only pick one. When you encounter a good fruit, you always wonder if you will encounter a better fruit later. But as you walk, you find that it is still the same fruit as before.

Even better. But when you went back to look for that fruit, you found that someone else had already picked it."

"Then is there a possibility that some good fruits are not willing to be picked by you?"

"this……"

After the two joked for a while, they started to get down to business.

"Xu You, you are here today. It is Teacher Wang who asked you to participate in our new project. Teacher Wang is not here, so I will give you an overview of what this project is about."

Listening to Zhao Weijia's narration, Xu You quickly understood the main research content of this topic.

This topic mainly studies the quantum phase transition of two different lattice models.

The so-called quantum phase transition, simply put, is a change in the quantum state of matter caused by changes in some order parameters of non-thermodynamic properties.

These order parameters include pressure, magnetic field, doping, etc.

Listening, Xu You also understood what the main problems encountered in the current project are.

"So, the numerical results of the Jaynes-Cummings lattice model and the Rabi lattice model quantum phase transition have relatively large errors with the theory?"

Zhao Weijia also nodded after hearing this.

"How do you describe this error... It is not too big to say it is, but it is not so ideal. We have also tried to use various methods to re-measure the numerical results, but we have not obtained particularly satisfactory data. What Teacher Wang means,

It would be better to further control this error."

"Let me see the data first."

Xu You was not in a hurry to analyze the reasons, but wanted to learn more about the details of the experiment before making his own judgment.

"Okay, I'll find it for you right now."

In front of Xu You, Zhao Weijia had a very good attitude, as if Xu You was a professor.

Of course, in terms of knowledge and ability, Xu You has indeed reached the level of a professor.

Immediately, Zhao Weijia found the corresponding data on the computer.

Xu You looked carefully and felt that there seemed to be some problems inside.

These data gave Xu You a strange feeling.

Although this error is still within the acceptable range.

But it is only on the edge of qualification.

Xu You vaguely felt that such a result might be very dangerous.

It may even affect key conclusions.

"Brother, let me take a look at the formula."

"Okay, please wait a moment."

As he said that, Zhao Weijia found out the formula part of the paper and talked about the derivation process of the formula.

At this time, Xu You suddenly noticed a detail issue.

"Wait a minute! Senior brother, this is an approximation, right?"

"Yes, we have taken an approximation for the phase change here. Theoretically, the approximation here should be negligible."

Xu You also knows this way of handling things.

Indeed, in theory, such an approximation has a very small impact on the results, so small that it can be completely ignored.

But the final error value is probably related to the approximation here.

Xu You continued to browse the experimental process and data processing methods in the paper, and kept thinking about something.

Finally, after repeated viewing and thinking.

Xu You found out the problem.

"Brother, although theoretically, the error of this approximation is negligible. But in fact, there is a process later that will amplify the error, so it will cause problems in the fitting of the numerical results."

Zhao Weijia also listened to Xu You's explanation, reanalyzed it himself, and finally understood what Xu You said.

"I see. If you hadn't said it, we wouldn't have discovered this problem at all."

Because everyone is used to this approximation, they will not subconsciously think it is problematic.

"But, Xu You, if we don't do approximation here, then this result cannot be expressed."

Because the formula that caused the problem is theoretically a formula of infinite length.

Only through approximation can the final result be expressed.

Otherwise, there will be no calculation at all.

"Yes, senior brother, I am also thinking about this issue."

At this time, Wang Xiangwu also came to the laboratory.

"Xu You, you are here."

"Well, I'm here, teacher."

"Have Wei Jia explained the problem to you?"

"Yes, senior brother has already explained the problem. We have just found the cause of the problem."

Wang Xiangwu was also shocked when he heard this.

We have been discussing this issue for several days, but no specific reason has been found.

As soon as Xu You came to the laboratory, he found out the reason?

"What's the reason? Come tell me!"

Next, Xu You told Wang Xiangwu what he had just said to Zhao Weijia.

Wang Xiangwu's reaction speed was obviously much faster than that of Zhao Weijia, but it took him a while to figure out the reason.

"Sure enough, I think there is something wrong inside. Fortunately, I came to see you, otherwise we don't know when we would find the cause."

At this time, everyone fell into deep thought again.
Chapter completed!