Hold the grass?

Land God?

Idol!

Seeing the man standing up, Zhang Zhongqing almost dropped his glasses on the ground.

When he thought that this big guy was sitting in his classroom and listening to such a class for half a day, he was really surprised and happy at the moment, it was like winning the lottery. I was surprised that I didn't notice it at all, but I was happy that I could brag to people when I went out, and we were also people who had taught Nobel Prize bigwigs.

However, although Zhang Zhongqing had mixed feelings in his heart, Lu Zhou didn't feel anything.

The classroom itself is also one of the places for academic exchange.

In the past, when he was in Princeton, he often asked his students to come up and speak for him.

At least in his view, there is no distinction between status and honor.

"Professor Lu, please." Professor Zhang immediately made a gesture of invitation and respectfully stepped out of the podium.

"Don't be so polite, I just happen to have some ideas."

Looking at his humble movements, Lu Zhou smiled embarrassedly.

It's too much time to continue to be polite.

Besides, he is not a polite person himself.

Walking to the blackboard and standing still, Lu Zhou picked up a piece of chalk.

"This kind of problem is not something that undergraduates can solve, and in addition to having a deep understanding of quantum chromodynamics, it also requires a deep grasp of functional analysis."

After a pause of two seconds, Lu Zhou continued, "However, it's not as complicated as everyone thinks. ”

As he spoke, he printed the chalk in his hand on the blackboard, and Lu Zhou calculated while writing on the board.

"Starting from the field theory, make a Feynman diagram, and use Feynman's rule to calculate the scattering amplitude to obtain the ......"

【iM=（ig²/|p'-p|²+mφ²）2m^ss'·2mδ^rr'】

【……】

"where mφ is the mass of the corresponding boson, and g is derived from the coupling constant in the interacting Ralferto. Combined with Prof. Zhang's previous calculation steps, V(q)...... can be obtained from the scattering cross-section."

【V（q）=-g²/（|q|²+mφ²）】

Writing this, Lu Zhou stopped the chalk in his hand, looked back at the students in the lecture hall, or looked confused or listening carefully, and smiled.

"It's pretty simple, but the next step will take some skill."

Students: "......"

MMP！

Where is it simpler???

Zhang Zhongqing, who was standing by and watching, was also at a loss.

It's not that he can't understand it, it's that he can't believe that someone can deduce these things on the spot in such a short period of time.

Doesn't this person need to spend time on calculations?

If that's the case, that's terrifying......

Without making any stops, Lu Zhou, who had finished speaking, turned to face the blackboard again and said lightly.

"Perform an inverse Fourier transform on it!"

The sound of chalk rubbing against the blackboard became faster and faster, and Zhang Zhongqing's expression standing next to him became more and more shocked. As for the students in the audience, they were looking at the blackboard blankly, even the top students who had already finished reading the textbooks in advance, faced with the complicated calculation process, they also had a bewildered expression.

At this moment, Lu Zhou didn't notice their expressions, and was already completely immersed in his own world.

Admittedly, these are some very basic things, but they are not yet basic enough to appear in example questions or exam papers.

However, as he thought deeply about these basic questions, as there were more and more steps on the blackboard, the glimmer of clarity in his heart became clearer and clearer.

Why do strong interaction forces only act at very short distances?

Or to put it another way, what makes nucleons only possible to form nuclei at extremely short distances?

The answer is obvious......

【……】

【V（r）=-g²/4πr·e^(-mφr)】

The chalk in his hand stopped, looking at the equation on the blackboard, Lu Zhou said slowly.

"The electromagnetic interaction exchanges photons, and the mass of the photons is zero, so for the electromagnetic interaction, V is proportional to 1/r."

"It is the meson acting between the nucleons that provides the nuclear force to the nucleons, with a mass of about 200 MeV, and it can be estimated that only the distance term is on the order of magnitude of minus fourteenth power of 10. The nuclear force acting between the two protons can cancel out the electromagnetic repulsion between the protons and the fusion reaction occurs. ”

Applause began in the first row.

Like a wave crashing on the shore, it spreads out to the back row.

Professor Zhang, who was standing next to him, also applauded unconsciously.

For most students, it's probably just a spectacle.

But for him, he saw a simpler way to solve the nuclear distance...... At least more concise than the two he remembered.

Incredibly, this was done on the spot in less than ten minutes......

At this moment, the shock in his heart is probably only clear to him.

At the same time, on the podium.

Although the classroom was already filled with applause, Lu Zhou, who was standing in front of the blackboard, was still immersed in his own world at the moment, so much so that when the applause stopped, he didn't notice it at all.

For the simple problem from earlier, this is the end of the calculation.

However, he was thinking about more than that.

According to the viewpoints of quantum field theory and quantum chromodynamics, the four fundamental forces can be unified with traditional particles.

For example, the components of the electric field can be constructed as non-commutative operators at different locations in space-time, and when the Hilbert space in which these operators operate, traditional particles, such as electrons, can be reinterpreted as the quantization of the Dirac field.

In this way, the difference between the field and the particle disappears.

Is it possible to describe the strong interaction in a concise mathematical form, like the einberg-Salam-Glasho theory of weak electricity, which describes the electromagnetic force and the weak interaction force in a unified way, and to unify it with the electromagnetic force?

Answering this question cannot solve the miniaturization of controlled fusion, nor can it bring any degree of innovation to the existing controlled fusion technology, but intuition tells Lu Zhou that if this problem can be solved theoretically, it may provide a clue, or an idea, to solve this problem......

Of course, it's not easy to do that.

For example, the strong interaction force is different from the weak interaction force, and it has a very typical problem......

The bell rang for the end of class, and Lu Zhou still stood there motionless, as if thinking about something.

Seeing that Lu Zhou didn't react, Zhang Zhongqing didn't want to announce his dismissal without authorization, let alone disturb his train of thought.

It was like this, about ten minutes.

Staring at the rows of concise calculations on the blackboard, Lu Zhou suddenly said to himself.

"How can the existence of mass gaps be explained in mathematical language?"

Hearing this question, Zhang Zhongqing was subconsciously stunned, and then his face turned red, and he was hesitant for a while like a student.

“…… Well, I really won't. ”

"I didn't ask you, you certainly won't ......"

Talking to himself, leaving behind the blackboard full of calculations, Lu Zhou turned and left the classroom, leaving the professor and student with a stunned face.

No one could answer this question.

After all, this is one of the most difficult propositions in particle physics about unified field theory at present.

At the same time, it is also recognized by the international mathematical community as one of the seven millennial problems......