Top Student

The problem is found though.

But the solution to the problem has no clue yet.

It is based on the original method to further seek the optimization scheme.

Or use any better method to further reduce the error and get the ideal numerical result?

For this, Xu You has no good solution for the time being.

"Teacher, let me think about it when I go back to see if there is any better approximation method. Can you copy this paper for me? I promise not to spread it outside."

Both Wang Xiangwu and Zhao Weijia trusted Xu You very much, and readily agreed to Xu You's request.

"Of course, you can copy it. If you have any other questions, you can contact me at any time."

Since Wang Xiangwu had already asked Xu You to help him, he naturally wouldn't trust Xu You.

After returning from Wang Xiangwu's laboratory, Xu You first returned to the dormitory.

Naturally, I went to pick up the suitcase.

Although it is to find a way to solve the problem, but in the case of insufficient knowledge, just thinking is definitely not enough.

Xu You still needs to further supplement relevant knowledge.

Seeing Xu You coming to the library, the library staff all paid attention to Xu You.

It has been three full days since Xu You came to the library last time.

Originally, Xu You would come to the library every two days.

Xu You also nodded to the staff.

There is no way, Xu You comes too often, and he is already familiar with them.

Because Xu You rarely attends classes, and rarely participates in various activities of the college.

Xu You is even more familiar with these library staff than with many college students.

With his precious suitcase, Xu You searched the library again.

When Xu You read a certain number of books.

A new problem also arises.

That is, there are many books that Xu You has already read.

The updating speed of books in the library is really not as fast as Xu You's reading speed.

It became more and more difficult for Xu You to find a good book, and it was a book that he hadn't read.

After coming out of the library, Xu You once again felt the eyes of the library staff.

Xu You looked at the librarian, hesitant to speak.

"What's the matter, student Xu You, is there any problem?"

The librarians also pay special attention to the library's largest customer.

"Teacher, I have a sentence, I don't know if I should say it or not."

"Student Xu You, tell me quickly."

"Can the updating speed of books in our library be a little faster? I'm about to start a book shortage."

The librarian said to himself, no matter how fast the update is, it is not enough for you to see it this way.

Sometimes, it's not a question of money, but that there really aren't that many new books.

"Okay, student Xu You, I will help you report this matter."

"Okay, excuse me, teacher."

After returning to the dormitory, Xu You sorted out the books and started a pleasant reading session.

There are two ways for Xu You to choose books.

One is to look at some knowledge that may not be used temporarily, but may be used in the future, as a knowledge reserve.

The other is to look at some knowledge that will be involved at present, as it is now.

On this issue, Xu You also believes that the approximate method must be applied.

And how to minimize the error caused by the approximation is the most critical issue.

"Huh? Mean-field approximation?"

At this time, Xu You suddenly discovered such a method.

In fact, Xu You had heard of this method before, but he hadn't really studied it carefully.

But this time, Xu You felt that this method was likely to be applied to this problem.

Mean field approximation is often used in the study of complex many-body problems.

The many-body problem with a huge number of interactions can be transformed into a single-body problem in which each particle is in a weak periodic field.

Although on similar problems, there is no application example of this method.

But Xu You felt that he could still give it a try.

"It won't work if you put it in directly, you still need to optimize it first."

Xu You opened the paper and optimized this method according to the characteristics of the research problem.

In this problem, there are many formulas involved, so it is still very complicated to deal with.

"Start here from the basic interaction between the two-level system and the light field. The derotation wave term decays rapidly to zero with time, and this must be negligible..."

Xu You deduced the formula step by step, taking extra care with every step.

"Huh~ Finally, the Hamiltonian has been released."

In this way, the application of the mean field approximation can finally begin.

"First, introduce a superfluid sequence parameter..."

Because the Hamiltonian obtained before is very difficult to calculate in detail.

Xu You must use an approximate method to calculate it, while maintaining extremely high precision and reducing errors as much as possible.

After another series of calculations, Xu You finally completed a further derivation.

"The high-order fluctuation term here can be ignored under the mean field approximation. In this way, the effective Hamiltonian can be calculated."

After writing the last formula, Xu You can finally breathe a sigh of relief.

Xu You didn't know if anyone had applied this method to a similar problem before him.

But according to Xu You's feeling, this new method will greatly reduce the error.

"Enter the data to verify."

Although Xu You's feelings are usually very accurate.

However, further verification is still needed to finally prove the suitability of the method.

Xu You input the effective Hamiltonian expression he had just deduced into the software, and started the fitting work again.

Looking at the newly emerged curve, which was closer to the theoretical curve, Xu You knew that his method should be correct.

"Sure enough, such an error is more ideal data!"

In order to ensure the applicability of this method, Xu You tested several other sets of data and further confirmed his idea.

"In this way, the problem should be solved."

This time, the time Xu You took was even less than half a day.

I haven't even finished half of the books I just borrowed.

Xu You didn't care too much, and hurried back to Wang Xiangwu's laboratory with his computer and draft paper.

Seeing Xu You come back, Zhao Weijia asked:

"What's the matter, Xu You, do you need more data?"

Zhao Weijia subconsciously thought that Xu You came back to find what he wanted because of insufficient information or data.

"No need. Brother, call Teacher Wang over here, I have found a better approximation method."