MTL - The Science Fiction World of Xueba-Chapter 410 Alice calls
Pang Xuelin smiled and secretly said, "I can't tell you, I can see this phenomenon from the paper given in the system reward."
Fortunately, before handing this experimental plan to Cao Yuan, Pang Xuelin had prepared his speech: "This is what I calculated."
"Calculated?"
Cao Yuan was startled, with a surprised expression on his face: "Professor Pang, have you figured out the theoretical mechanism of superconductivity?"
Pang Xuelin shook his head with a smile and said, "It hasn't been completely figured out yet, but there is a general idea. This theoretical prediction only roughly verified my conjecture."
"What guess?"
Pang Xuelin said: "It is well known that the early discovery of metal simple superconductors based on classical BCS theory can basically explain. The core of BCS theory is that lattice distortion induces electrons to form Cooper pairs. The essence of conduction is the transmission of electron flow, and the superconducting state is An electronic system condenses into a low-energy state through electronic pairing. In the usual BCS superconducting image, electronic pairing and aggregation occur simultaneously. The superconducting state is protected by a pairing energy gap, and only when thermal fluctuations are sufficient to destroy this energy gap , The superconductor is destroyed. "
"But for unconventional superconductors, such as heavy fermion compound superconductors, high temperature copper oxide superconductors, iron-based superconductors, and superconductors formed under ultrahigh pressure conditions such as hydrogen sulfide and lanthanide, which have been recently studied very hot, In the superconducting state, a certain energy in the spin fluctuation spectrum will be collectively excited to form 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. Studying 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 others could not help looking at each other.
They certainly know this theory. In condensed matter physics, studying the relationship between these unconventional superconductors and quantum fluctuations has become a hot topic in condensed matter physics in recent years.
"Professor Pang, have you found a connection between unconventional superconductivity and quantum fluctuations?"
Dong Chenglin curious.
Pang Xuelin said with a smile: "The unconventional superconductivity of unconventional superconductors and the physical description of quantum critical behavior have long exceeded the theoretical framework of the classic Landau Fermi liquid theory and traditional superconducting theory. I dare not say that I have found The relationship between them, but my research in this area has made some progress. I don't know if you have seen Sean Schwartz, a physicist at Max Planck, and Zwos, a physicist at MIT. Marlo published two papers on heavy fermion 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 the heavy fermion compound superconductor CeCu2Si2 material has two different superconducting states, and the low voltage superconducting phase is similar to other heavy fermion superconducting states. , Another new high-pressure superconducting state appears near the valence electron quantum transition point. At the magnetically induced superconducting quantum phase transition point, the Wiedemann-Franz law, which is generally followed in metals, is destroyed in the heavy fermion superconductor 5. "
"In addition. In 1998, the MIT Zvos Marlow team verified by experiments that the Fulde-Ferrell-Larkin-Ovikov (FFLO) superconducting phase predicted in the 1960s may exist in the 5 superconducting upper critical magnetic field. Near. Below the upper critical magnetic field, 5 exhibits a rich magnetic flux phase diagram and cannot be described by the traditional Abrikosov flux-matrix model. When the antiferromagnetic phase of 5 was gradually suppressed by pressure, they found , Magnetically induced quantum phase transitions appear in the superconducting phase. "
"In the paper, Zworth Marlow also gave the multibody wave function in the strong correlation model of heavy fermion compounds, and tried to obtain a clear superconducting state by solving the completely strict solution in the multiwave body function. But unfortunately, there are some problems with the multi-wave body functions listed by Marlow, and the solution is relatively difficult. Therefore, this paper has not attracted large-scale attention in the academic community. Some time ago, I combed and copied the relevant questions. Thesis. The existence of this thesis was discovered. "
"These two papers were both recently discovered in the relevant literature on superconductor research. Then, based on these two papers, I re-derived a mathematical model of the multiwave body function. As a result, I found that unconventional superconductors The strong correlation model is equivalent to the superconducting phenomenon of the graphene two-dimensional electronic system discovered by Cao Yuan in the electric field. Therefore, based on this, I did further calculations to find the two-dimensional graphene electronic system. A strict solution to the superconducting phenomenon in the electric field. It turns out that there should be two solutions. The other is the two-dimensional graphene that you just verified in your experiment in the microwave irradiation at an angle of 2.5 degrees. Electronic systems should also be superconducting. "
Everyone in the conference room looked at each other with shocking faces.
Pang Xuelin said lightly, but everyone understands the difficulty.
Since the discovery of superconductors, there have been more than ten million papers related to superconductors. Pang Xuelin was able to find Schwartz and Marlow's papers from so many papers, and based on them, made further improvements and gave multibody functions. The rigorous solution of Cao Yuan, and linking it with Cao Yuan's achievements, is enough to show how powerful the big man is.
Without any step in it, today's results will not appear.
Cao Yuan smiled bitterly: "Professor Pang, you still haven't made any progress. Theoretically predicting the existence of a superconductor is enough to cause a strong shock in the physics community."
Pang Xuelin smiled and said, "Where is this called prophecy? Superconducting phenomena exist in graphene two-dimensional electronic systems. I just calculated another condition that may exist."
Pang Xuelin was a little embarrassed by the respected eyes of everyone. The superconducting phenomenon of graphene under the 2.5-degree angle and microwave irradiation is described in the system paper. He just made the conclusion based on this phenomenon. Back-calculated, and then came up with the mathematical model of the multi-wave body function.
The two papers by Sean Schwartz and Zvos Marlowe were but his excuses to relieve the doubts of everyone.
At this time, Zhou Tong was curious: "Professor Pang, is it possible to derive the critical conditions for the existence of room temperature superconductors through the mathematical model of the multiwave body function you gave? Or even predict the existence of some superconductors?"
Pang Xuelin nodded and said, "It does exist, but I still lack two important data."
"What data?"
Cao Yuandao.
Pang Xuelin said: "First, the condensing 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 condensing energy and the superconducting state and the normal state as soon as possible. Measurement of energy difference. As for the design of the experimental scheme, everyone needs to discuss and decide. "
Pang Xuelin's voice dropped, and the conference room suddenly calmed down, and everyone frowned.
It is very difficult to accurately measure the condensing energy of superconducting states, because the number of supercurrent electrons in high-temperature superconductors is very small.
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 around ten Tesla.
Therefore, it is also difficult to accurately measure the energy difference between the superconducting state and the normal state.
Cao Yuandao: "Maybe we can try with electronically doped high temperature superconductors."
Pang Xuelin said: "How do you 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 the superconducting condensing energy and magnetically excited resonance peaks. For example, high-temperature superconductors, by measuring low-energy quasiparticle excitation, The ground state of the chirped energy gap will have Fermi arc characteristics. After entering the superconducting state, a new energy gap will gradually be established on these Fermi arcs. Its size reflects the scale of superconducting energy. Through this model, we It is possible to measure high-quality superconducting specific heat data in a wide temperature range and accurately obtain the evolution relationship of condensing energy with magnetic field. "
Dong Chenglin also agreed: "This method is good. In addition, we can measure the resonance peaks in the magnetic excitation spectrum by neutron scattering experiments."
Pang Xuelin laughed and said, "Very well, the subsequent experimental work will be left to you."
"Professor Pang, rest assured, we must complete the measurement of superconducting condensing energy as soon as possible."
Zhou Tong laughed with a fist.
Cao Yuan laughed: "Okay, let's start preparing now, old Dong, arrange your work, and I will take Professor Pang to see President Lu."
"it is good!"
Dong Chenglin nodded.
At this time, Pang Xuelin laughed and said, "Don't leave after work. In the evening, I invite you to have a meal and toil everyone. In addition, this project is a cooperative project between Qiantang Laboratory and Luzhou National Laboratory of Microscale Physical Science. In the process of participating in this project, your monthly salary and bonus standards will be issued in accordance with the standards of Qiantang Labs. The day after tomorrow at the latest, you should be able to receive the first bonus of the year. "
"Long live Professor Pang!"
"Haha, I love work!"
"I feel instantly full of motivation."
...
The crowd cheered.
Pang Xuelin smiled, and then went to the principal'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 already informed the University of Science and Technology, and the president of the University of Science and Technology Lu Dongming certainly knew that Pang Xuelin was coming.
However, Pang Xuelin demanded that he do not carry out a welcome ceremony or the like with great fanfare, so Lu Dongming also followed the good and did not deliberately pick up Pang Xuelin.
In the principal's office, Lu Dongming, president of the University of Science and Technology of China, has been waiting for a long time.
Lu Dongming was in his early fifties, tall and wearing black-rimmed glasses.
What surprised Pang Xuelin was that Lu Dongming's principal had another big brother in his room.
"Hello, Principal Lu! Welcome to HKUST for guidance and visit."
"Hello, principal Lu."
Pang Xuelin and Lu Dongming shook hands.
"By the way, let me introduce you. This is Professor Pan Jianwei, Executive Vice President of the University of Science and Technology and Dean of the Institute of Quantum Information and Quantum Science.
Lu Dongming pointed to a middle-aged man next to him who looked elegant and thoughtful.
"Hello Professor Pan!"
"Hello Professor Pang."
Pan Jianwei also shook hands with Pang Xuelin.
For Pan Jianwei, Pang Xuelin can be described as Lei Guaner.
This big guy has a very high appearance rate in the domestic academic circle, and he can be called one of the largest experimental physicists in China.
It is because of his push that China can later take the lead in the field of quantum communication and become the world's top player in this field.
Although there are a lot of people on the Internet, some people think that he is too high-profile, and some people think that his academic achievements are not famous, and there are no original theoretical results. It is far from the Nobel Prize.
However, in Pang Xuelin's view, the real strength of this big man lies in the combination of broad vision, excellent organizational skills and rare experimental talents, which almost pushes China from the quantum communication desert to the world's first. Arrays are far ahead in the field of experiments.
As for academic level, let alone.
PRL sent to hand soft.
In 2012, invited by the "Modern Physics Review" (RMP), Pan Jianwei published a long review paper on "Multiphoton Entanglement and Interferometrics".
Physicists who can be invited to publish a review by the RMP come here in one stroke.
In 2017, it was selected as one of the top ten scientific figures in the world by Nature Magazine.
In a sense, this big man can be called the icon of the Chinese University of Science and Technology. UU Kanshu www.uukanshu.com
If it is not quantum communication and quantum computer is not the main research direction of Qiantang Lab at present, Pang Xuelin has a digging mind.
Next, the four chatted in the north of the principal's room, Tian Nanhai. Pang Xuelin and Lu Dongming also reached an agreement on a series of cooperation between the University of Science and Technology, the Qiantang Laboratory, and the Jiangcheng Advanced Institute.
That night, Lu Dongming hosted a special feast for Pang Xuelin.
In addition to being accompanied by Pan Jianwei and Cao Yuan, Dong Chenglin and Zhou Tong were also invited.
After dinner, Pang Xuelin just returned to the hotel, and his cell phone ring suddenly.
Caller ID is a strange foreign number.
Pang Xuelin froze slightly and pressed the answer key.
On the phone came Alice's lazy voice: "Professor Pang, how are you?"
Pang Xuelin froze slightly, surprised a little: "Alice, where are you now?"
Alice said lightly: "I'm in Seattle. I just got my U.S. passport. It's a good time. I want to live well here."
Pang Xuelin laughed and said, "That's good. If you need help, you can always contact me."
"You don't need me to help you?"
Pang Xuelin said: "We are friends, aren't we?"
"That's right!" Alice laughed and said, "Let's do it. I'll find you if I have time."
Hanging up the phone, Pang Xuelin shook his head and smiled.
For Alice, he didn't have any special thoughts, and it was just helpless to bring her to this world. I hope she can live a peaceful life in the future.
