Chapter 605: Why do nuclei come together?

It didn't seem long before the class started.
Gently opened the back door and glanced back at the middle-aged professor facing the blackboard in the classroom. Lu Zhou didn't bother him and other students listening to the lesson, and didn't even bother the buddies who were sleeping on the side beside the door. Pai found an inconspicuous spot and sat down very low-key.
Inspiration does not come to you, you have to find it yourself.
Lu Zhou agreed with a sentence Fermi once said, and thinking about why obvious problems are obvious helps to deepen the understanding of those esoteric problems.
Whether it is in physics or mathematics, there are precedents to follow.
When I was in Princeton, if I encountered a problem that I could n’t understand, Lu Zhou would take the time to give a few lessons to undergraduate students, or occasionally go to other professors for inspiration.
For example, while studying Goldbach's conjecture, Professor Fefferman gave a great lesson to him. And this is not because of how esoteric things he talked about in class, on the contrary, what he said at the time was just something very easy to understand ...
After completing the blackboard writing on the blackboard, the middle-aged professor standing on the podium cleared his throat and said.
"Quantum mechanics is a very esoteric discipline. If you really understand it deeply, its existence will even subvert your understanding of the microworld, physics, and even classic philosophy. Although I know my voice may be good Helps sleep, but I do n’t recommend that you start sleeping from the first class ... "
There was a good laugh in the classroom, and Lu Zhou sitting in the back row couldn't help smiling.
It seems that this professor can be regarded as a young scholar with a certain level of teaching. At least, he did not read the preface according to the PPT as soon as he opened the textbook.
It's just that his voice wasn't loud and probably a slapstick.
At least the man sitting next to Lu Zhou has no plans to wake up.
A glance at the few who had woke up, and the few who had not yet woke up, the middle-aged professor shrugged humorously and continued to preach indifferently.
"We all know that the STAR-2 demonstration reactor over Haizhou some time ago was successfully ignited under the command of Professor Lu of our school. As a result, our country's controllable fusion power generation technology has also taken the forefront of the world, becoming The only country with a commercial reactor. "
Hearing this sentence, Lu Zhou, who was sitting in the back row listening to the lesson, suddenly felt embarrassed.
How can one talk about quantum mechanics?
This is not plasma physics.
However, the professor on the stage was very energetic. The students in the ladder classroom were obviously full of interest in this topic. Even the buddy who slept soundly beside Lu Zhou raised his head in a sleepy eye. Come, look at the podium aggressively.
At this time, Lu Zhou noticed that the teacher ’s name and phone number were written on the front page of the quantum mechanics textbook under his arm.
Zhang Zhongqing?
never heard of that……
"... According to public data, the peak temperature of the core of the STAR-2 demonstration reactor or the current Pangu reactor is as high as 130 million degrees Celsius, which is nearly 9 times the temperature of the solar center!"
Looking at the students exclaiming in the classroom, Professor Zhang standing on the stage was secretly pleased, knowing that he had successfully captured the students' attention, he immediately hit the railway while he was hot.
"At such a temperature, ordinary materials must not be able to withstand it. Therefore, our country's STAR-2 demonstration reactor uses a magnetic confinement method to confine the deuterium and tritium mixture in the ionized state I participating in the reaction in a closed magnetic cage. . "
"Then the question is coming, I want to ask students, why does controlled fusion need such a high temperature to carry out the reaction? Or in other words, why can't fusion reactions take place at normal temperature?"
The classroom was quiet.
The buddy sitting next to Lu Zhou pouted his lips and muttered softly.
"Is this nonsense?"
Just hearing this groan, Lu Zhou raised his eyebrows with interest, and was about to ask him what he thought. But before Lu Zhou spoke, he continued.
"... If this can be done at room temperature, then not everything can be fused."
Lu Zhou: "..."
"Is there any classmate who can stand up and talk?"
At a glance at the classroom where no one raised their hands, Professor Zhang standing on the podium had to add, "This question has normal grades."
Huh!
Hearing the usual results, more than half of the people in the classroom raised their hands instantly.
"I know!" After being instructed by the professor, the female Xueba wearing glasses sitting in the first row stood up and replied quickly. .Only when the two nuclei are close enough can the strong interaction force be able to overcome the Coulomb repulsion and aggregate the two nuclei together. Macroscopically, only by increasing the heat in the system and accelerating the thermal movement of the molecules in the system, can it Make the nuclei collide with enough kinetic energy to cause fusion reaction. "
"Good answer," wrote a score on the roster, and the middle-aged professor cleared his throat and continued with a smile. "Then the question comes, have you thought about why the strong interaction is only in the extreme? Can it happen at short distances? "
"Because ... is short-range force?"
"This is an explanation of high school physics textbooks, and it's no different to say or not," Professor Zhang smiled, motioned to the student who stood up to answer, and continued, "You are now college students, except you should know In addition to 'what', you should understand 'why'. "
"Quantum field theory tells us that the interactions between particles are not extended by distance, but are carried out by some kind of boson as the medium. For example, electromagnetic interactions exchange photons, and strong interactions exchange gluons or mesons. Weak Interaction exchanges W and Z bosons ... someone may ask, what does this have to do with the range of force we are talking about? "
Then, Professor Zhang turned to the blackboard and preached as he wrote.
"Assuming that two resolvable fermions scatter, then under the Berne approximation, we can find that the scattering cross section and the interaction can have the following relationship ..."
[Amp; amp; lt; piTpamp; amp; gt; =-iVδ,]
[……]
who am I?
where am I?
Looking up at the calculations on the blackboard, the dude sitting next to Lu Zhou had an aggressive expression, wondering if he had slept through the classroom.
"Grass? Isn't it about nuclear fusion ... what day is it today?"
Obviously it was just two seconds away, but he had the feeling of missing a semester course.
It's not just him.
People sitting in the classroom can understand less than half of what Professor Zhang is talking about.
Looking at the aggressive man next to him, Lu Zhou smiled and asked softly.
"Want to know?"
"Think ... can you understand?" The buddy glanced at Lu Zhou with a grimace, probably because he didn't wake up, so he didn't respond to who was sitting next to him.
Lu Zhou smiled and said, "If you want, then I'll teach you."
After stopping the chalk in his hand, Professor Zhang turned around and looked at the students with aggravated faces, his mouth cornered.
It is normal to read.
Quantum mechanics itself is a difficult point in physics ~ EbookFREE.me ~ Especially when it comes to calculations, it is impossible without a certain mathematical foundation.
Speaking of himself, there is nothing wrong with remembering the conclusion, but if he calculates it on the spot, it may not necessarily be calculated before class.
"The calculation process is very complicated," leaving the chalk in his hand on the desk, Professor Zhang put his hands behind his back and smiling, "If anyone can complete the rest, my usual grade in this course Give it to him, and this class will not be used in the future. "
Dead in the stepped classroom was quiet.
The students looked at each other.
Even those graduate students who came to take courses were aggressive.
Professor Zhang shook his head with a smile. Just as he planned to arrange the problem as a thinking problem, a voice came from the back of the classroom.
"Can I use the blackboard?"
Zhang Zhongqing: "... ????"