Great Country Academician

In addition to news related to the manned spaceflight project, Wen Yuanhang also brought another news related to the establishment of a large-scale strong particle collider project.

On the Thursday of the first week after New Year's Day in 2022, the Science Project Center is preparing to hold a discussion meeting on the construction of a large-scale strong particle collider belonging to Huaguo.

This meeting is purely an internal meeting of the academic community, and only scholars from the fields of high-energy physics and particle physics, as well as relevant personnel from the science and technology community, will participate.

From site selection, to budget, to the implementation of technical details, all aspects need to be discussed and confirmed through meetings.

Xu Chuan definitely needs to participate in this meeting.

Aside from his request to build a large strong particle collider, as a Nobel Prize winner in physics, his opinion is also crucial.

What's more, inert neutrinos, dark matter, dark energy, and methods of mathematically calculating the energy orbits of physical particles are all related to him.

After Wen Yuanhang left, Xu Chuan took his attention back and returned to his work.

After dealing with some daily mail and related matters, he returned to Nantah University and took out the manuscripts for calculating KL-66 materials from the drawer in the office.

Since we will go to the capital for a meeting in one week, we will deal with the matter of inviting Academician Sun Ze, the deputy chief designer of the lunar exploration project, at that time.

The mechanism of the KL-66 material has been raised to a very high priority for the next research.

The most important thing is that in this regard, there are not many people who can help him. It is difficult to find someone in China to cooperate with him in research.

The inversion asymmetric spin-orbit coupling of Cu atoms has an impact on the energy band structure and electronic properties of the material, and the two branches of the Fermi arc state electrons connect the c-axis to break the inversion symmetry theory.

Looking at the data and theories on the manuscript paper, Xu Chuan fell into deep thought.

The problem of strongly correlated electron systems is one of the core problems of condensed matter physics.

But when it comes to things in this area, let alone Huaguo, there are not many breakthroughs in the world.

More importantly, the basic physical processes involved in the strong correlation phenomena discovered so far are often difficult to be accurately described in the existing physical framework, so this research is extremely difficult to deal with by traditional experimental methods and theoretical methods.

Maybe Mr. Yang Zhenxi Yang is a very good candidate for communication. His research on condensed matter physics can be said to be the top in the world.

But now that the old man was ninety-nine years old, Xu Chuan really couldn't bear to disturb the old man's old age.

After thinking quietly for a while, Xu Chuan continued to write on the manuscript paper he wrote last time:

【Research on correlation effect and superconductivity in multi-orbital strongly correlated system】

"S = (kB/e)ln(ge/gh)"

"Start with a tightly bound interacting Hamiltonian: [H=i∑jTi, jaii, σaj, σ+i, i′∑j, j′Uii′aiσai′σ′ajσ′aja]

"The second interaction term has a different contribution: [Uii′ = Vi, i′→∑i, i′Vii′ inii′], i.e. under the density-density interaction.”

"Physically, this is because the two Vanier center wave functions must be antisymmetric, and the lowest energy state is a symmetrical arrangement of the two spins (and the antisymmetric spatial wavefunction). When i→j is forbidden or suppressed, i.e. the overlap between adjacent orbitals is small, and Uiii = U/2→ΣiVii′inii dominates, giving the Hubbard model."

"But how do you explain this aspect of the theory mathematically?"

At the desk, Xu Chuan frowned as he stared at the theory he had written on the manuscript paper.

The most troublesome point in the strongly correlated electron system is here.

"Can a site with the Hubbard model work?"

Thinking about it, he wrote down a new line of formula: [H = Ht+ Hu =-t(a↑a↑+a↓a↓+h.c)]

This is the particle number conservation model. If half-filling (where singular physics arises) is used, the Hilbert space consists of 6 states, including 2 fully polarized states |↑, ↑\u003e and |↓, ↓\u003e and 4 states with S=0.

Theoretically speaking, the first two states are self-contained states. And the Hamiltonian can be diagonalized in 4×4 spaceSz=0.

On the manuscript paper, Xu Chuan checked the mathematical formulas and thoughts in his heart.

After a while, he stopped to finish his pen.

The Hubbard model does work, but it cannot be used in multi-site situations.

And this is obviously not applicable to the mechanism in KL-66.

After the Cu atom replaces the lead site, it splits into two Weyl nodes with opposite chirality through the Dirac cone, forming a multi-site effect, and the KL-66 material has strong diamagnetism and can even float in a strong magnetic field. core mechanism.

"Perhaps, I should change the route and use Fermi fluid theory to calculate its electricity and magnetism."

Thinking about it, Xu Chuan changed his mind and started to set off.

It is extremely difficult to explain an unfamiliar mechanism, and he didn't expect to find useful clues within a day or two.

I don't know how long it has passed, but a voice came from my ear.

"Professor, you have your algebraic geometry class scheduled for this afternoon, and the class is due in fifteen minutes."

In the office, the voice of his newly recruited student Rong Xinji sounded.

Hearing the voice, Xu Chuan came back to his senses, nodded, and said, "Okay, I see."

Out of curiosity, Rong Xinji glanced at the manuscript paper on Xu Chuan's desk.

My mentor has been sitting and frowning studying something for almost the whole afternoon. He wants to see what problem the idol is working on again. Maybe he still has a chance to take advantage of the opportunity.

After all, I am a graduate student anyway, and IMO gold medalist, so I still have some strength!

【S =(kB/e)ln(ge/gh)H=i∑jTi，jaii，σaj，σ+i，i′∑j，j′Uii′aiσai】

【.】

Rong Xinji:? ? ? ?

Fuck? What the hell is this?

Why doesn't he even know math symbols? ? ?

After struggling to move away from the manuscript paper, he couldn't help swallowing, and asked, "Professor, what are you studying?"

Xu Chuan glanced at him and asked with a smile, "Can you understand?"

Rong Xinji shook his head.

Can he say he understands a ghost?

He is an IMO gold medalist, a graduate student in mathematics, and he doesn't even know the meaning of the symbols in the formula.

No one will believe this, okay?

So hopeless.

Hearing this, Xu Chuan smiled and said, "It's normal not to understand, this is not something in the field of pure mathematics."

After a slight pause, he then asked: "Do you know the strongly correlated electron system in physics?"

Regarding this question, Rong Xinji nodded. Although he is not a physics major, he still knows about such famous things as strong associations.

Smiling, Xu Chuan continued: "These on the manuscript paper are the relationship between the correlation effect and superconductivity in the multi-track strong correlation system through mathematical calculations."

Hearing this, Rong Xinji was instantly stunned again.

What do you calculate? ? ? ?

Looking at the dazed look of his student, Xu Chuan smiled and got up and patted him on the shoulder, saying: "Study hard, if you are interested in mathematics and physics, you can read more books on physics. You can also choose this direction for your PhD.”

"As of right now, it's not something you should be thinking about."

PS: Ask for a monthly pass in the second shift