For the next month, Pang Xuelin stayed at USTC and did not leave.

Room-temperature superconducting materials are the key to the electromagnetic orbital ejection system, and Pang Xuelin is ready to complete his efforts and strive to solve the problem of room-temperature superconductors before the next time comes.

Of course, in addition to discussing the experimental plan with Cao Yuan, Pang Xuelin was also invited to hold two lectures at the University of Science and Technology of China, each of which was full of seats, attracting the active participation of many students from the University of Science and Technology of China.

As for the experiment, Pang Xuelin can not provide much help, so he can only provide some suggestions, and what to do can only be handed over to Cao Yuan and Dong Chenglin.

Fortunately, Cao Yuan and Dong Chenglin are both very good experimental physicists, and they basically perfectly present the experimental effect that Pang Xuelin wants.

A month passed in a flash.

That afternoon, with a burst of cheers from Zhou Tong, everyone in the laboratory focused their eyes on Zhou Tong.

Even Pang Xuelin is no exception.

Only then did Zhou Tong realize that he had lost his temper, stood up a little embarrassed, and said with a smile: "Professor Pang, Professor Cao, I have already processed all the condensation energy data of the superconducting state and the energy difference data between the superconducting state and the normal state. ”

The crowd immediately flocked to him.

Pang Xuelin said: "How about the accuracy?" ”

Zhou Tong said: "Professor Pang, this is the result of my measurement and analysis of 200,000 sets of data, and the estimated error is no more than 1/10,000. ”

Pang Xuelin nodded, with a satisfied smile on his face, and said, "It's hard work, you can print out the data and give me a copy later." ”

"Okay."

Zhou Tong nodded.

Cao Yuan and the others also breathed a sigh of relief.

For the past month, the lights in the lab have been on almost 24 hours a day.

Including Cao Yuan and Pang Xuelin, each of them worked at least 14 hours a day.

It is precisely because of this hard work that they were able to complete the experimental work in just one month.

Of course, everyone works so hard, and the material conditions are naturally indispensable.

Even Wei Wenxuan and Tan Song, two doctoral students, Pang Xuelin also gave treatment far beyond ordinary doctoral students.

At this time, Pang Xuelin said with a smile: "Everyone has worked hard in the past month, Professor Cao, let's give everyone a good vacation, rest for a while, and leave the rest of the work to me." ”

"Good!"

Cao Yuan nodded and said.

Pang Xuelin didn't stay long, and after getting the data, he went straight back to the expert building arranged by USTC for himself.

Zuo Yiqiu was watching TV in the living room a little bored.

For the past month, Pang Xuelin has spent most of his time in the laboratory.

Zuo Yiqiu was idle, except for occasionally helping Pang Xuelin deal with the administrative affairs of Jiang University and Qiantang Laboratory, the rest of the time, she was basically free.

Seeing Pang Xuelin enter the house, Zuo Yiqiu was a little curious: "Professor Pang, why did you come back so early today?" ”

In the past, Pang Xuelin would not come back if he didn't stay in the laboratory until eleven or twelve o'clock in the evening, but now it is only two o'clock in the afternoon.

Pang Xuelin said with a smile: "The data from the laboratory has come out, and then I will retreat for a while." You help me out there to keep out the visitors, so that no one disturbs me. ”

Zuo Yiqiu was slightly stunned, and said curiously: "Professor Pang, how long are you going to retreat this time?" ”

"It's a week, it's a month, and if there's anything really important, come back to me."

Pang Xuelin said with a smile.

"So long?"

"What's wrong?"

"I didn't ...... It's nothing? By the way, Professor Pang, you are in retreat, what should Qi Xin and Yao Bingxia do when they look for you? ”

Pang Xuelin said: "I'll tell them later, they will understand." ”

"Oh."

Zuo Yiqiu nodded and said no more.

Pang Xuelin also ignored Zuo Yiqiu and went upstairs.

When he came to the study, Pang Xuelin called Qi Xin and Yao Bingxia respectively, telling them that he was going to retreat for a period of time and that he couldn't contact them every day.

Finally appeased the two daughters, Pang Xuelin called his parents and Liu Tingbo, Xu Xingguo, Li Changqing, Shi Yi and others, and notified them one by one.

Subsequently, Pang Xuelin took out the manuscript paper and began to formally retreat and study.

Time passed.

One day, two days......

One week, two weeks......

Unconsciously, half a month has passed.

After another all-nighter, Pang Xuelin rubbed his eyes a little tiredly.

Day and night of high-intensity mental work, even after genetic modification of the body, is a little unbearable.

Pang Xuelin stretched out for a long time, looking at the data on the manuscript paper in front of him, his eyes became brighter than ever.

If nothing else, a new system of physical theories has taken shape before his eyes.

"It's finally done."

Pang Xuelin muttered to himself.

He went to the window and pulled the curtain open with a thud.

Outside the window, the morning light is faint, and you can hear the chirping of birds.

On the nearby road, there are already many teachers and students who are exercising in the morning.

The glow of the morning sun could already be seen in the distance, and Pang Xuelin's eyes narrowed slightly, as if he saw the light of the new world.

Then, he picked up the mobile phone that he hadn't used for a long time and dialed Cao Yuan's number.

Cao Yuan was obviously still sleeping, and when the phone was connected, his voice was still confused.

But Pang Xuelin's words made Cao Yuan feel agitated and completely sobered up.

"Professor Cao, I think I've found a unified theory of superconductivity."

"What?" Cao Yuan suddenly got up from the bed and said a little incredulously, "Professor Pang, you say it again." ”

Pang Xuelin said with a smile: "Professor Cao, I have found the theoretical mechanism of superconductivity. ”

"Professor Pang, are you in the Expert Building now? I'm looking for you! ”

"Don't worry, you call everyone over, we'll see you in the lab at half past eight."

"Oh, okay then."

Cao Yuan hesitated for a moment, and suppressed the urge to go to Pang Xuelin immediately.

When Pang Xuelin came out of the house, he smelled the smell of breakfast coming from the kitchen.

Gollum......

Pang Xuelin felt the protest from his stomach.

In the past half a month, he has been studying day and night, and the average daily sleep time is less than two hours, and the problem of eating is basically solved by Zuo Yiqiu.

Perhaps hearing the movement, Zuo Yiqiu came out of the kitchen, looked at Pang Xuelin with some surprise and said, "Professor Pang, are you out of the customs?" ”

Pang Xuelin was a little surprised and said, "Are you making breakfast?" Why don't you go to the cafeteria and buy it? ”

Zuo Yiqiu glared at Pang Xuelin angrily and said, "Professor Pang, I made all the food you ate during this time. ”

"You did it?" Pang Xuelin was slightly stunned, immediately reacted, and hurriedly smiled, "I said that the food has been so delicious recently." ”

Zuo Yiqiu rolled his eyes.

How could she not see that Pang Xuelin was deliberately remedy, with his dedication to research, it was strange that he could taste the taste of the food.

I was also worried that the food in the cafeteria of the University of Science and Technology would not meet Pang Xuelin's appetite, so I worked hard to cook meals for him for so many days.

However, Zuo Yiqiu still suppressed his anger and said, "Professor Pang, are you going out?" ”

Pang Xuelin nodded and said, "Wait a minute, go to the laboratory." ”

Zuo Yiqiu said: "Then you wait a while, I cooked preserved egg and lean porridge, and it will be fine immediately." ”

More than ten minutes later, the steaming porridge with preserved eggs and lean pork was brought to the table.

The two were drinking porridge at the dining table, and Zuo Yiqiu sat opposite Pang Xuelin and said, "Professor Pang, how long will we stay at HKUST?" ”

Pang Xuelin said with a smile: "If nothing else, I should be able to return to Jiangcheng today." ”

"Today?"

Zuo Yiqiu's eyes widened, a little surprised.

"What's wrong?"

Pang Xuelin wondered.

"I didn't ...... It's nothing. ”

Zuo Yiqiu hurriedly shook his head.

After breakfast, Pang Xuelin went straight to the laboratory.

Seeing Pang Xuelin's figure disappear at the door, Zuo Yiqiu hurriedly took out his mobile phone and dialed a call.

……

By the time Pang Xuelin arrived at the laboratory, Cao Yuan, Zhou Tong, and Dong Chenglin had already arrived at the laboratory.

Pang Xuelin said: "Everyone is here, right? Let's go to the conference room to talk. ”

Everyone nodded, and followed Pang Xuelin into the conference room.

"Professor Pang, I heard Lao Cao say that you have completed the theoretical construction of the superconductivity theory?"

Dong Chenglin was the first to speak.

Cao Yuan and Zhou Tong all focused their eyes on Pang Xuelin, with hopeful expressions on their faces.

If you change to someone else, everyone will naturally have doubts.

But Pang Xuelin is different, not to mention the academic status of this big man, just the super academic ability he showed before made everyone full of confidence in him.

Pang Xuelin smiled slightly, nodded and said, "I have indeed completed the construction of the superconductivity theory. ”

"Professor Pang, tell us about it."

Zhou Tong looked like a little fan girl and couldn't wait.

In fact, not only Zhou Tong, almost everyone has similar eyes.

Everyone understands what it means to complete the theoretical construction of the superconducting mechanism.

Pang Xuelin no longer hung everyone's appetite, and said with a smile: "Okay, then I'll talk about it first." During this time, I proved that the TJ model does not exhibit S-wave nearest neighbor pairing, generalized η pairing, generalized out-of-place Q pairing, and dx2-y2 wave pairing superconducting long programs in any non-zero temperature one-dimensional and two-dimensional narrowband (including sub-neighbor hopping, etc.). If there is an excitation gap in the charge excitation spectrum of the system, then these pairing long programs will also be excluded at zero temperature, and our results hold true for arbitrary J-values and arbitrary electron filling. ”

As he spoke, Pang Xuelin picked up the marker and wrote on the whiteboard behind him.

Including Cao Yuan, everyone looked intently at the formula on the whiteboard, while trying to listen to Pang Xuelin's explanation.

Pang continued: "The simple understanding is that in superconductors, thermal fluctuations can destroy superconductivity, and various long programs are formed at low temperatures, such as BCS and BEC. However, if we take into account the interaction forces, if the attraction is large enough, then the transition temperature will be high enough. ”

"For example, strong correlation systems, heavy fermion compounds in current experiments, copper-based superconductivity and iron-based superconductivity, and even hydrogen sulfide and hydrogen lanthanide under high pressure, are all strongly correlated materials. The mechanism of high-temperature superconductivity established by the strong correlation system is the superconductivity long program of quantum fluctuation enhancement. In condensed matter systems, all long programs are perturbated on the basis of the ground state of Fermi liquid. For example, superconductivity, charge density wave [CDW], ferromagnetic sequence [Stoner FM], antiferromagnetic sequence [AFM] or spin density wave [SDW] and so on. Therefore, we have the same understanding of these long programs, through some mechanisms to make the Fermi surface unstable to open the energy gap, and then establish a long program and keep it stable at low temperatures, as long as the thermal fluctuation energy scale kT is close to the energy gap, the long program will be destroyed. ”

"In the same way, this also understands why various long programs are always competing or suppressing each other, in fact, it is to compare which of these long programs can open a larger energy gap at the Fermi surface, and the system establishes one long program, and will not build another at the same time."

"The difference between the strong correlation system and the traditional condensed matter system is that the spin correlation between electrons must be considered, which leads to quantum fluctuations, and its ground state changes from the Fermi liquid state to the spin liquid state or other states, which leads to strong quantum fluctuations in the magnetic sequence, the magnetic sequence is suppressed, and then the superconducting sequence is established. What is more interesting is that the quantum fluctuation in the magnetic sequence will also strengthen the superconducting order. The electrons are close to the Mott state due to the spin fluctuations, which strengthens the superconducting pairing interaction and increases the transition temperature. In ferromagnetic superconductors such as UCoGe, the superconducting state is strengthened by quantum fluctuations near the quantum phase transition point of the anisotropic ferromagnetic state. ”

……

Minutes and seconds passed.

Before you know it, an hour has passed.

The whiteboard was also written by Pang Xuelin.

Finally, Pang Xuelin put down the marker, pointed to the last formula on the whiteboard and said, "Pass this formula." We can substitute the parameters of certain materials and predict at what kind of temperature and pressure they can become superconductors. ”

Pang Xuelin turned around and looked at the people who were still in confusion and shock.

Wei Wenxuan and Tan Song, the two doctoral students, looked dazed, as if they were listening to a book from heaven.

Dong Chenglin and Zhou Tong fell into deep thought.

Only Cao Yuan reacted immediately and applauded gently.

Bang Bang Bang ......

The applause quickly resounded throughout the room.

Cao Yuan said loudly: "Professor Pang, congratulations, this is completely a Nobel Prize-level achievement!" ”

Seeing that some people in the team still didn't seem to understand, Cao Yuan said: "In general, Professor Pang's work explains why the vast majority of superconductors must be below the temperature of liquid nitrogen and liquid helium to exhibit superconductivity, or at millions of atmospheres in order to exhibit high-temperature superconductivity. There is even a precise calculation formula, through which we can deduce the superconducting transition temperature and external conditions of some superconducting materials, and even deduce the state of some materials in a superconducting state. ”

At this time, Dong Chenglin also nodded and said: "It's really amazing, Professor Pang, if nothing else, with this set of theories, the Nobel Prize in Physics should be in your pocket." However, in order to fully understand your theory, I am afraid that you need a very good mathematical foundation. ”