Chapter 606 Why Do Nucleons Gather Together?

Classes seem to have just begun.

Gently pushed open the back door, and glanced at the middle-aged professor with his back to the classroom writing on the blackboard. Lu Zhou didn't disturb him or the other students, or even the buddy who was sleeping on his stomach next to the door. The platoon found an inconspicuous seat and sat down very low-key.

Inspiration will not come to you by yourself, you have to find it yourself.

Lu Zhou agreed with what Fermi once said. Thinking about why some obvious problems are obvious can help deepen the understanding of those esoteric problems.

Whether this sentence is placed in physics or mathematics, there are precedents to follow.

When he was in Princeton before, if Lu Zhou encountered a problem that he couldn't understand, he would take time to teach undergraduates a few classes, or occasionally go to other professors' classes to find inspiration.

For example, when studying Goldbach's conjecture, a number theory class taught by Professor Fefferman gave him a lot of inspiration. And this is not because of the profound things he said in class, on the contrary, what he said at that time were only some very easy-to-understand things...

After finishing writing on the blackboard, the middle-aged professor standing on the podium cleared his throat and spoke.

"Quantum mechanics is a very esoteric subject. If you really go deep into it, its existence will even subvert your understanding of the microscopic world, physics, and even classical philosophy. Although I know my voice may be very good Sleep aid, but I don't recommend you to sleep from the first class..."

There was good-natured laughter in the classroom, and Lu Zhou, who was sitting in the back row, couldn't help but smile.

It seems that this professor is also a young scholar with some teaching skills, at least he didn't read the preface from the PPT as soon as he opened the textbook.

However, his voice is not loud, which may be a flaw.

At least the buddy sitting next to Lu Zhou has no plans to wake up yet.

Glancing at those who had woken up and those who hadn't woken up, the middle-aged professor shrugged humorously, and continued to preach without caring.

"We all know that some time ago, the STAR-2 demonstration reactor in Haizhou was successfully ignited under the command of our school's Professor Lu, and our country's controllable fusion power generation technology has also been at the forefront of the world. The only country that has built a commercial pile."

Hearing this sentence, Lu Zhou, who was sitting in the back row listening to the class, suddenly felt embarrassed.

How can quantum mechanics be involved in him?

This is not plasma physics.

However, the professor on the stage spoke very enthusiastically, and the students in the lecture theater were obviously full of interest in this topic. Even the buddy who was sleeping soundly next to Lu Zhou raised his head sleepily. Come, look at the podium with a dazed expression.

At this time, Lu Zhou noticed that on the title page of the quantum mechanics textbook under his arm, there was the teacher's name and phone number.

Zhang Zhongqing?

never heard of that……

"...According to public data, the STAR-2 demonstration reactor—or the current Pangu reactor—has a peak internal temperature of 130 million degrees Celsius, which is nearly nine times the temperature at the center of the sun!"

Looking at the students who were exclamating in the classroom, Professor Zhang standing on the stage was secretly happy. Knowing that he had successfully captured the attention of the students, he immediately hit the railway while it was hot.

"General materials can't bear such a temperature. Therefore, our country's STAR-2 demonstration reactor adopts a magnetic confinement method to confine the deuterium-tritium mixture in the ionization state I that participates in the reaction in a closed magnetic cage. .”

"Then here comes the question. I would like to ask students, why does controllable fusion require such a high temperature for the reaction? Or in other words, why can't the fusion reaction be carried out at room temperature?"

The classroom fell silent.

The buddy sitting next to Lu Zhou curled his lips and muttered in a low voice.

"Isn't this nonsense?"

Hearing this rant, Lu Zhou raised his eyebrows with interest, and was about to ask him what he thought. But before Lu Zhou could speak, he continued.

"...If this can be done at room temperature, then not everything can undergo nuclear fusion."

Lu Zhou: "..."

"Is there any student who can stand up and talk?"

After glancing at the classroom where no one raised their hands, Professor Zhang standing on the podium could only add, "This question has normal results."

Swish Swish Swish!

Hearing that there are usual grades, more than half of the people in the classroom immediately raised their hands.

"I know!" After being signaled by the professor, the female schoolmaster wearing glasses sitting in the first row stood up and replied quickly, "Because the nucleus is positively charged, there is Coulomb repulsion between the nucleus and the nucleus. .Only when the two nuclei are close enough, the strong interaction force can overcome the Coulomb repulsion and bring the two nuclei together. On the macroscopic level, only by increasing the heat in the system and accelerating the thermal motion of the molecules in the system can the The atomic nuclei collide together with sufficient kinetic energy to undergo a fusion reaction."

"That's a good answer," the middle-aged professor wrote down a score on the roster, cleared his throat, and continued with a smile, "Then here comes the question, have you ever thought about why the strong interaction force is only Can it happen at a short distance?"

"Because... it's a short-range force?"

"This is an explanation from a high school physics textbook, and it's the same as if you didn't say it." Professor Zhang smiled, motioned the student who stood up to answer to sit down, and continued, "You are now college students, except that you should know In addition to the 'what', it is more important to understand the 'why'."

"Quantum field theory tells us that the interaction between particles is not an action at a distance, but unfolds through some kind of boson as a medium. For example, the electromagnetic interaction exchanges photons, the strong interaction exchanges gluons or mesons, and the weak Interacting and exchanging W and Z bosons... Some people may ask, what does this have to do with the range of force we are talking about?"

As he spoke, Professor Zhang turned to face the blackboard, speaking while writing.

"Assuming that there is scattering between two resolvable fermions (p+k→p'+k'), then under the Berne approximation, the relationship between the scattering cross section and the interaction can be obtained as follows..."

【

=-iV(q)(2π)δ(Ep'-Ep), (q=p'-p)】

【…】

who I am?

where am I?

Looking up at the calculations on the blackboard, the buddy sitting next to Lu Zhou had a dazed expression on his face, wondering if he fell asleep in class until time travel.

"Hold the grass? Isn't it talking about nuclear fusion... what date is it today?"

Although he was only distracted for two seconds, he felt like he had missed a semester of class.

In fact it wasn't just him.

The people sitting in the classroom can understand less than half of what this Professor Zhang said above.

Looking at the bewildered buddy next to him, Lu Zhou smiled and asked softly.

"Want to know?"

"I think...you can understand?" The buddy looked at Lu Zhou in a daze, maybe because he didn't wake up, but he didn't realize who the person sitting next to him was.

Lu Zhou smiled and said, "If you want to, then I will teach you."

After stopping the chalk in his hand, Professor Zhang turned around and looked at the stunned students with the corners of his mouth curled up.

It's normal not to understand.

Quantum mechanics itself is a difficult point in physics.

Especially when it comes to calculations, it is impossible without a certain mathematical foundation.

Speaking of himself alone, there is no problem in remembering a conclusion, but if he is asked to calculate it on the spot, it may not be possible to calculate it before get out of class ends.

"The calculation process is very complicated." Throwing the chalk in his hand on the desk, Professor Zhang put his hands behind his back and said with a smile. Give it all to him, and this class will not be used in the future.”

It was dead quiet in the lecture theater.

The students looked at each other in blank dismay.

Even the postgraduates who came to take classes were dumbfounded.

Professor Zhang shook his head with a smile. Just as he was about to arrange this question as a thinking question, a voice came from the back row of the classroom.

"Can I use the blackboard?"

Zhang Zhongqing: "...???"