The Science Fiction World of Xueba

Pang Xuelin smiled, and thought to himself: "I can't tell you, I saw this phenomenon from the papers given in the system rewards."

Fortunately, before handing over the experimental plan to Cao Yuan, Pang Xuelin had already prepared his speech: "This is what I calculated."

"Calculated?"

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

Pang Xuelin shook his head with a smile, and said: "I haven't fully figured it out yet, but I just have a rough idea. This theoretical prediction just roughly verified one of my conjectures."

"What guess?"

Pang Xuelin said: "As we all know, the classical BCS theory can basically explain the early discovered metal-based superconductors. The core of the BCS theory is that lattice distortion induces electrons to form Cooper pairs. The essence of conduction is the transmission of electron flow, and superconductivity is A low-energy state in which the electron system condenses through electron pairing. In the usual BCS superconducting image, electron pairing and condensation occur simultaneously. The superconducting state is protected by a pairing energy gap that is only destroyed by thermal fluctuations , the superconductivity is destroyed.”

"However, for unconventional superconductors, such as heavy fermion compound superconductors, cuprate high-temperature superconductors, iron-based superconductors, and superconductors formed under ultra-high pressure conditions such as hydrogen sulfide and hydrogen lanthanide, which are very hot in recent research, once entering In the superconducting state, there will be a collective excitation at a certain energy on the spin fluctuation spectrum, forming a resonance peak of a specific energy. Preliminary experiments have shown that this resonance peak is related to the number of superconducting electrons in the superconducting state After the sample enters the normal state, this resonance peak disappears immediately. To study the relationship between this resonance peak and superconductivity is the key to the current research on the mechanism of high-temperature superconductivity.”

Cao Yuan and the others could not help but look at each other.

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

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

Dong Chenglin asked 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 superconducting theory. I dare not say that I have found it." The relationship between them, but my research in this area has indeed made some progress. I don’t know if you have seen the German Max Planck physicist Sean Schwartz and the MIT physicist Zvos Marlowe's two papers on heavy fermion compound superconductors in 1995 and 1998?"

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

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

"In addition. In 1998, the MIT Zvos Marlowe team verified through experiments that the Fulde-Ferrell-Larkin-Ovikov (FFLO) superconducting phase predicted in the 1960s may exist in the superconducting critical magnetic field of 5 Near the upper critical magnetic field, 5 exhibits a rich flux phase diagram, which cannot be described by the traditional Abrikosov flux lattice model. When the antiferromagnetic phase of 5 is gradually suppressed by pressure, they found that , the magnetoinduced quantum phase transition occurs within the superconducting phase.

"

"In the paper, Zvos Marlowe also gave the many-body wave function in the strong correlation model of heavy fermion compound materials, trying to obtain a clear superconducting state by solving the complete strict solution in the multi-wave body function But it is a pity that there are certain problems in the multi-wave body function listed by Marlowe, and the solution is relatively difficult. Therefore, this paper has not attracted large-scale attention from the academic community. paper. The existence of this paper was discovered.”

"I found these two papers in the related literature on superconductor research recently, and then based on these two papers, I deduced a mathematical model of the multi-wave body function, and found that the unconventional superconductor The strong correlation model of the graphene two-dimensional electronic system has equivalent characteristics with the superconductivity of the graphene two-dimensional electronic system discovered by Cao Yuan. So, on this basis, I made further calculations and obtained the graphene two-dimensional electronic system The strict solution of the phenomenon of superconductivity in the electric field. It turns out that there should be two solutions, and the other is the two-dimensional graphene in the microwave irradiation at an angle of 2.5 degrees that you just verified in the experiment not long ago. Electronic systems should also have superconductivity."

Everyone in the conference room looked at each other with shock on their faces.

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

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

Without any step in this, it is impossible to have the current results.

Cao Yuan smiled bitterly and said, "Professor Pang, you are still making no progress. Simply predicting the existence of a superconductor theoretically is enough to cause violent shocks in the physics world."

Pang Xuelin smiled and said: "This is not a prediction. The phenomenon of superconductivity already exists in the graphene two-dimensional electronic system. I just calculated another possible condition."

Pang Xuelin was a little embarrassed by the admiration of everyone. The phenomenon of superconductivity in graphene under the condition of 2.5 degrees included angle and microwave irradiation was described in the system paper. He just made a conclusion based on this phenomenon. Reverse deduction, and then came up with the mathematical model of the multi-wave body function.

The two papers by Sean Schwartz and Zvos Marlowe were just his excuses to clear up the doubts in everyone's mind.

At this time, Zhou Tong asked curiously: "Professor Pang, is it possible to deduce the critical conditions for the existence of room temperature superconductors through the mathematical model of the multi-wave body function you gave? Even predict the existence of certain superconductors?"

Pang Xuelin nodded and said, "It is indeed possible, but I still lack two important data."

"What data?"

Cao Yuan said.

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

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

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

In addition, in hole-doped high-temperature superconductors, the critical magnetic field (upper critical magnetic field) for destroying superconductivity is very high, and it is generally difficult to completely destroy superconductivity with a commonly used laboratory magnetic field of about ten 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 electronically doped high-temperature superconductors."

Pang Xuelin said: "How to say?"

Cao Yuandao: "The critical magnetic field on the electronically doped high-temperature superconductor is not very high, which provides conditions for us to study the relationship between superconducting condensation energy and magnetic excitation resonance peak. For example, high-temperature superconductors, by measuring low-energy quasiparticle excitation, its The pseudogap ground state will have the characteristics of Fermi arcs. After entering the superconducting state, a new energy gap will be gradually established on these Fermi arcs. Its size reflects the scale of superconducting energy. Through this model, we can High-quality superconducting specific heat data can be measured in a wide temperature range and the evolution relationship of condensation energy with magnetic field can be obtained accurately."

Dong Chenglin also agreed: "This method is good. In addition, we can measure the resonant peaks on the magnetic excitation spectrum through neutron scattering experiments."

Pang Xuelin laughed and said, "Very well, I will leave the follow-up experimental work to you."

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

Zhou Tong on the side clenched his fists and said with a smile.

Cao Yuan smiled and said, "Okay, let's start preparing now, old Dong, you arrange work, and I will take Professor Pang to meet Principal Lu."

"good!"

Dong Chenglin nodded.

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

"Long live Professor Pang!"

"Haha, I love working!"

"In an instant, I felt energized."

...

Everyone immediately cheered.

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

Pang Xuelin had notified the University of Science and Technology of this trip to the University of Science and Technology of China. 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 hold any welcome ceremony with much fanfare, so Lu Dongming followed suit and did not go to pick Pang Xuelin on purpose.

When we came to the principal's office, Lu Dongming, the principal of the University of Science and Technology of China, had been waiting for a long time.

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

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

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

"Principal Lu, hello."

Pang Xuelin and Lu Dongming shook hands.

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

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

"Professor Pan, hello!"

"Professor Pang, hello."

Pan Jianwei also shook hands with Pang Xuelin.

For Pan Jianwei, Pang Xuelin is like a thunderbolt.

This boss has a very high appearance rate in domestic academic circles, and he can be regarded as one of the most famous experimental physicists in China.

It is precisely because of his strong promotion that China can catch up from behind in the field of quantum communication and become the world's top player in this field.

Although there are quite a few people criticizing Pan on the Internet, some people think that he is too high-profile, and some people think that his academic achievements are not famous, and he has no original theoretical achievements, and he is far away from the Nobel Prize.

But in Pang Xuelin's view, the real strength of this boss lies in his combination of broad vision, excellent organizational ability and rare experimental talent, and he has pushed China from the desert of quantum communication to the world's number one almost by himself. Arrays are far ahead in the experimental field.

As for the academic level, let alone.

The PRL is soft.

In 2012, invited by the Review of Modern Physics (RMP), Pan Jianwei published a long review paper on "Multiphoton Entanglement and Interferometry" on it.

Physicists who can be invited by RMP to publish a review on it can be counted from all over China.

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

In a sense, this boss can be called the iconic figure of USTC.

If it weren't for quantum communication and quantum computers not being the main research direction of Qiantang Laboratory, Pang Xuelin would have started poaching people.

Next, the four of them chatted all over the world in the principal's office. Pang Xuelin and Lu Dongming also reached an agreement on a series of cooperation between HKUST, Qiantang Laboratory and Jiangcheng Advanced Research Institute.

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

Apart from Pan Jianwei and Cao Yuan, Dong Chenglin and Zhou Tong were also invited to accompany them.

After eating, just as Pang Xuelin returned to the hotel, his cell phone rang suddenly.

The caller ID is an unfamiliar foreign number.

Pang Xuelin was slightly taken aback, and pressed the answer button.

Alice's lazy voice came from the other end of the phone: "Professor Pang, how are you?"

Pang Xuelin was taken aback for a moment, and said in surprise, "Alice, where are you now?"

Alice said lightly: "I'm in Seattle and just got my American 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, "That's fine, I'll find you if I'm free."

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

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