Pang Xuelin smiled and said secretly in his heart: "I can't tell you that I saw this phenomenon from the paper given in the system reward." ”

But fortunately, before handing over this experimental plan to Cao Yuan, Pang Xuelin had already prepared a rhetoric: "This is what I calculated. ”

"Calculated?"

Cao Yuan was taken aback, and a surprised expression appeared on his face: "Professor Pang, have you figured out the theoretical mechanism of the superconductivity phenomenon?" ”

Pang Xuelin shook his head with a smile and said, "I haven't figured it out completely, I just have a general idea." This theoretical prediction only roughly verified one of my conjectures. ”

"What conjecture?"

Pang Xuelin said: "As we all know, the early discovery of metal-based superconductors can be basically explained by the classical BCS theory. The core of the BCS theory is that lattice distortion induces electrons to form Cooper pairs. The essence of electrical conduction is the transport of electron streams, and superconducting state is a low-energy state condensed by the pairing of electrons in an electronic system. In the usual BCS superconducting image, electron pairing and condensation occur simultaneously. The superconducting state is protected by a paired energy gap, and the superconductivity is destroyed only when the thermal fluctuations are sufficient to destroy this energy gap. ”

"However, for unconventional superconductors, such as heavy fermion compound superconductors, copper oxide high-temperature superconductors, iron-based superconductors, and superconductors formed under ultra-high pressure conditions such as hydrogen sulfide and hydrogen lanthanide, which have been very hotly studied recently, once they enter the superconducting state, there will be a collective excitation of a certain energy on the spin fluctuation spectrum, forming a formant peak of a specific energy. Preliminary experiments have shown that this formant is related to the number of superconducting electrons in the superconducting state. This formant disappears as soon as the sample enters the normal state. Studying the relationship between this formant and superconductivity is the key to the current research on the mechanism of high-temperature superconductivity. ”

Cao Yuan and the others couldn't help but look at each other.

Of course, they know this theory, and in condensed matter physics, studying the relationship between these unconventional superconductivity and quantum fluctuations has become a hot topic in the condensed matter physics community in recent years.

"Professor Pang, have you found the connection between unconventional superconductivity and quantum fluctuations?"

Dong Chenglin said curiously.

Pang Xuelin said with a smile: "The physical description of unconventional superconductivity and quantum critical behavior of unconventional superconductors has long surpassed the theoretical framework of the classical Landau Fermi liquid theory and the traditional BCS superconductivity theory, and I dare not say that I have found a relationship between them, but my research in this area has indeed made some progress." I don't know if you have read two papers on heavy fermion superconductors published by Sean Schwartz, a physicist at the Max Planck Institute in Germany, and Zworth Marlowe, a physicist at the Massachusetts Institute of Technology, in 1995 and 1998 respectively? ”

Cao Yuan, Dong Chenglin, and Zhou Tong looked at each other and shook their heads.

Pang Xuelin said: "In these two papers, Sean Schwartz discovered that the heavy fermion compound superconductor CeCu2Si2 material has two different superconducting states, the low-voltage superconducting phase is similar to other heavy fermion superconducting states, and another new high-voltage superconducting state appears near the valence electron quantum phase transition point. At the point of magnetostrictive superconducting quantum phase transition, the Wiedemann-Franz law, which is commonly followed in metals, is broken in heavy fermion superconductors5. ”

"Also. In 1998, the Zworth Marlow team at the Massachusetts Institute of Technology proved through experiments that the Fulde-Ferrell-Larkin-Ovikov (FFLO) superconducting phase, which had been predicted in the 60s of the 20th century, may exist near the critical magnetic field on superconductor 5. Below the upper critical magnetic field, 5 exhibits a rich flux phase diagram and cannot be described by the traditional Abrikosov flux lattice model. When the antiferromagnetic phase of 5 was gradually suppressed by the pressure, they found that the magnetostrictive quantum phase transition occurred in the superconducting phase. ”

In the paper, Zworth-Marlow also gave the many-body wave function in the strong correlation model of heavy fermion compound materials, trying to derive a definite superconducting state by solving the completely strict solution in the multi-wave body function. But unfortunately, the multi-wave body function listed by Marlow has certain problems and is relatively difficult to solve. Therefore, the paper did not attract significant attention from the academic community. Some time ago, I was combing through the papers related to the topic. The existence of this paper was discovered. ”

"These two papers were discovered by me recently in the literature on superconductor research, and then I re-deduced a mathematical model of multi-wavelength body function on the basis of these two papers, and found that the strong correlation model of unconventional superconductors is equivalent to the superconductivity phenomenon in the electric field of graphene two-dimensional electronic system discovered by Cao Yuan. So, on this basis, I made further calculations and found a strict solution to the superconductivity phenomenon of graphene two-dimensional electronic system in an electric field. It turns out that there should be two solutions for this solution, and the other is that the two-dimensional graphene electronic system under microwave irradiation at an angle of 2.5 degrees that you just verified in the experiment should also have superconductivity. ”

Everyone in the conference room looked at each other one by one, and their faces showed shock.

Pang Xuelin said it lightly, but everyone understands the difficulty in this.

Since the discovery of superconductors, there have been thousands of papers related to superconductors, and Pang Xuelin was able to find the papers of Schwartz and Marlowe from so many papers, and on the basis of them, he made further improvements, gave a strict solution of the many-body function, and linked it with Cao Yuan's achievements, which is enough to show how awesome this big guy is.

Without any of these steps, the results we have achieved today would not have been possible.

Cao Yuan smiled bitterly and said: "Professor Pang, you are still not making progress, just theoretically predicting the existence of a superconductor is enough to cause a violent shock in the physics community." ”

Pang Xuelin smiled and said: "Where is this called prophecy, there is superconductivity in the graphene two-dimensional electronic system, and I just calculated another possible condition." ”

Pang Xuelin was a little embarrassed by the reverence of everyone, the superconductivity phenomenon of graphene at an angle of 2.5 degrees and microwave irradiation conditions was described in the system paper, he just deduced the conclusion according to this phenomenon, and then came up with the mathematical model of the multi-wave body function.

The essays by Sean Schwartz and Zworth Marlowe were merely excuses to dispel doubts in the minds of the people.

At this time, Zhou Tong was curious: "Professor Pang, is it possible to deduce the critical conditions for the existence of room-temperature superconductors through the mathematical model of multi-wavelength function you gave?" Or even predict the existence of certain superconductors? ”

Pang Xuelin nodded and said, "There is indeed such a possibility, but I still lack two important data. ”

"What data?"

Cao Yuandao.

Pang Xuelin said: "First, the condensation energy of superconducting states. Second, the energy difference between the superconducting state and the normal state. I hope that we will gather everyone's efforts to complete the measurement of the condensed energy of the superconducting state and the energy difference between the superconducting state and the normal state as soon as possible. As for the design of the experimental protocol, it needs to be discussed and decided. ”

Pang Xuelin's words fell, and the conference room suddenly fell silent, and everyone frowned.

Accurately measuring the condensation energy of a superconducting state is very difficult because high-temperature superconductors have a very small number of superfluid electrons.

In addition, in hole-doped high-temperature superconductors, the critical magnetic field (upper critical magnetic field) that destroys superconductivity is very high, and it is generally difficult to completely destroy superconductivity with a magnetic field commonly used in laboratories of about 10 Tesla.

Therefore, it is also difficult to accurately measure the energy difference between the superconducting state and the normal state.

Cao Yuan said: "Maybe we can try it with electron-doped high-temperature superconductors. ”

Pang Xuelin said: "What do you say? ”

"The critical magnetic field on electron-doped high-temperature superconductors is not very high, which provides conditions for us to study the relationship between superconducting condensation energy and magnetic excitation resonances," Cao said. For example, the high-temperature superconductor PrLaCeCuO, by measuring the excitation of low-energy quasiparticles, its pseudo-energy gap ground state will have the characteristics of Fermi arcs, and after entering the superconducting state, a new energy gap will gradually be established on these Fermi arcs, and its size reflects the scale of superconducting energy. ”

Dong Chenglin also agreed: "This method is good. In addition, neutron scattering experiments can be used to measure the formants on the magnetic excitation spectrum. ”

Pang Xuelin laughed and said, "Very good, then the follow-up experimental work will be handed over to you." ”

"Professor Pang, don't worry, we will definitely complete the measurement of the condensation energy of the superconducting state as soon as possible."

Zhou Tong on the side clenched his fists and smiled.

Cao Yuan said with a smile: "Okay, then let's start preparing now, Lao Dong, you arrange the work, and I will take Professor Pang to meet President Lu." ”

"Good!"

Dong Chenglin nodded.

At this time, Pang Xuelin said with a smile: "Don't leave after work, I'll treat everyone to a meal in the evening and treat everyone." In addition, this project is a cooperation project between the Qiantang Laboratory and the Luzhou National Experimental Center for Physical Science at the Microscale, so in the process of participating in this project, your monthly salary and bonus standards will be paid according to the standards of the Qiantang Laboratory, and you should be able to receive the first bonus of the year at the latest the day after tomorrow. ”

"Long live Professor Pang!"

"Haha, I love work!"

"I instantly felt like I was energized."

……

The crowd burst into cheers.

Pang Xuelin smiled, and then went to the president's office of the University of Science and Technology with Cao Yuan.

On this trip to the University of Science and Technology of China, Pang Xuelin had already informed the University of Science and Technology, and of course Lu Dongming, the president of the University of Science and Technology of China, also knew that Pang Xuelin was coming.

However, Pang Xuelin asked not to make a big deal about the welcome ceremony or anything like that, so Lu Dongming was also kind and did not go out of his way to pick up Pang Xuelin.

Coming to the president's office, Lu Dongming, president of the University of Science and Technology of China, has been waiting for a long time.

Lu Dongming is in his early fifties, tall and wears a pair of black-rimmed glasses.

To Pang Xuelin's surprise, there was another big man in Lu Dongming's principal's room.

"Hello, Principal Lu! Welcome to HKUST for a guided visit. ”

"Hello, Principal Lu."

Pang Xuelin and Lu Dongming shook hands.

"By the way, let me introduce you to Professor Pan Jianwei, Executive Vice President of HKUST and Dean of the Institute of Quantum Information and Quantum Science."

Lu Dongming pointed to a middle-aged man beside him who looked medium and elegant.

"Hello, Professor Pan!"

"Hello, Professor Pang."

Pan Jianwei also shook hands with Pang Xuelin.

For Pan Jianwei, Pang Xuelin can be described as thunderous.

This bigwig has a very high appearance rate in the domestic academic community, and can be called one of the most famous experimental physicists in China.

It is precisely because of his push that China has been able to catch up in the field of quantum communication and become the world's top player in this field.

Although there are many people who have blackened Pan on the Internet, some people think that he is too high-profile, and some people think that his academic achievements are not as famous as those of the famous, and there are no original theoretical achievements, and he is far from the Nobel Prize.

But in Pang Xuelin's view, the real awesomeness of this big guy lies in the combination of broad vision, excellent organizational ability and rare experimental talent, almost single-handedly, pushing China from a quantum communication desert to the world's first array, and is far ahead in the field of experiments.

As for the academic level, that's even less to say.

PRL sent to the soft.

In 2012, at the invitation of the Modern Physical Review (RMP), Jianwei Pan published a long review paper on "Multiphoton Entanglement and Interferometry".

The physicists who were able to be invited by the RMP to publish a review on it were all over China in one slap in the face.

In 2017, he was selected as one of the top ten scientific figures in the world by Nature magazine.

In a sense, this big guy can be called an iconic figure of USTC.

If it weren't for the fact that quantum communication and quantum computers are not the main research directions of the Qiantang Laboratory at present, Pang Xuelin would have the intention of digging people.

Next, the four chatted in the president's office, and Pang Xuelin and Lu Dongming also reached an agreement on a series of cooperation between HKUST and Qiantang Laboratory and Jiangcheng Institute for Advanced Study.

That night, Lu Dongming hosted a special banquet for Pang Xuelin.

In addition to Pan Jianwei and Cao Yuan, Dong Chenglin and Zhou Tong were also invited.

After eating, Pang Xuelin had just returned to the hotel when his mobile phone rang suddenly.

The caller ID is an unfamiliar foreign number.

Pang Xuelin was slightly stunned and pressed the answer button.

Alice's somewhat lazy voice came from the other end of the phone: "Professor Pang, hello." ”

Pang Xuelin was slightly stunned, and said with some surprise: "Alice, where are you now?" ”

Alice said lightly: "I'm in Seattle, I just got my U.S. passport, this era is not bad, I want to live a good life here." ”

Pang Xuelin laughed and said, "That's good, if you need help with anything, you can contact me at any time." ”

"You don't need me to do things for you?"

Pang Xuelin said: "We are friends, aren't we? ”

"That's right!" Alice laughed and said, "Okay, I'll look for you when I have time." ”

Hanging up the phone, Pang Xuelin shook his head and smiled.

He didn't have any special thoughts about Alice, and he brought her into this world just out of helplessness, hoping that she could live a peaceful life in the future.