cosmological constant,

A very magical existence.

Xu Mang, who was a minute ago, had already silently raised his hands when he faced this question, indicating that he had surrendered, but just after this minute, he evolved from a mortal to a god, and instantly understood the universal constant.

At this point,

The other students were very sympathetic to Xu Mang's experience, they didn't mean to laugh at it, after all, a terminally ill person, but at the last moment of his life, he had to be insulted by physics, it was so tragic...

A male classmate sitting near Xu Mang cautiously said to Xu Mang: "Xu Mang... The cosmological constant is a cosmic field strength, a term proportional to the gauge tensor. ”

However...

The voice was too small for Xu Mang to hear.

"Professor!"

"Are you asking me to talk about the cosmological constant?" Xu Mang stood up and said with a serious face: "If you insist on asking me to talk about the cosmological constant, I am afraid that it will delay your class time and the happiness of your classmates in acquiring and enjoying knowledge." ”

“？？？”

“？？？”

“？？？”

it!

Is this a self-indulgence before death?

The thirty or so students in the theoretical physics class present looked at Xu Mang in horror.

The professor is also a hard-tempered person, he has long had a big opinion about Xu Mang lying on the table all day long, not because he is disgusted with Xu Mang's bad learning, but he has a positive attitude towards Xu Mang's IQ, otherwise he would not have achieved so many achievements besides physics.

What the professor is worried about is that Xu Mang shows a salted fish all day long, which will affect the surrounding students, and the most important thing in learning is an atmosphere, and a role model is needed.

Obviously,

Now the atmosphere has been disrupted and the role model has been gradually distorted.

"Yes!"

"The next time is when you tell about the cosmological constant. The professor nodded.

"Then I..."

"Can I stand in your place?" Xu Mang said with a smile: "I'm sorry professor, I'm used to it... I also take classes on weekdays, giving advanced math classes to students majoring in optics. ”

After Xu Mang's reminder, many people reacted that he was actually a lecturer!

Nima,

Also reported in September, everyone else is a dual-department graduate student and has become a senior math lecturer, while he is sitting in the classroom, listening to the professor's lectures.

It's all human, why is there such a big difference?

afterwards

Xu Mang stood in front of the podium, and a strange and familiar feeling returned.

"The system... I want the full contents of the cosmological constant!"

[Recognized by the system, the exchange value of all contents of the cosmological constant: 1500 (physical skill)]

No way!

Is it so expensive?

However, the arrow had to be fired.

Xu Mang endured the pain and could only pay 1,500 skill points.

Incidentally

Memory mode is enabled.

After all, it took so many skill points to explain a cosmological constant, how can you memorize this knowledge, right?

"Ahem!"

"To understand what the cosmological constant is, I have to start with Einstein's general theory of relativity. After that, Xu Mang wrote down a field equation on the blackboard, and then turned to his classmates and said, "You should know what this is, right... This is the Einstein field equation, which depicts gravitational force as the curvature of space. ”

The concept of spatial curvature,

All the students in the room understood that the concept was proven in the macrocosm, and of course this was not to abandon the law of gravitation, and that the curvature of space was just a fine-tuning of Galileo and Newton's theories.

"This side is energy, and this side is the shape of space-time. Xu Mang said: "This is an equation based on the static universe, which is used to calculate the universe. ”

"But..."

"What this equation calculates is a dynamic universe. Xu Mang paused: "The dynamic universe doesn't need me to explain, right?"

The students present shook their heads one after another, showing that they didn't want to talk nonsense!

"Oh..."

"Einstein at the time believed that the universe was static and that the universe should remain still. Xu Mang wrote down another field equation, but this time it contained an term, the Λ*g_uv universe term.

Incidentally

Underneath this cosmic item, two wavy lines are drawn.

"This is Einstein raised his hand, and suddenly added a thing, which is the cosmological constant, Λ*g_uv. Xu Mang paused and said silently: "That is, an unknown cosmic energy that he envisioned." ”

"As long as you give a certain value, you can keep the universe still and not change again. Xu Mang continued: "It's a pity that even if this cosmic constant is added, the calculated universe is still dynamic. ”

"Later..."

"Edwin Hubble discovered that the universe is expanding, how to discover it, and how to prove it, Mr. Xu will not explain too much here. Xu Mang smiled: "Then Einstein felt that he had made the biggest mistake in his life, adding an unnecessary cosmological constant." ”

This...

The professor standing under the podium listened to Xu Mang's popular science with a little surprise on his face.

Originally, I thought that Xu Mang was just a brief introduction to the cosmological constant, but who knew that this guy would narrate the past life of the cosmological constant, and he would narrate it so concisely and easily understandable, he was a talent!

Below...

I guess that's the point!

I hope Xu Mang can bring some surprises!

The professor knows that the introduction in front is not important, but the content in the back is important.

However, one of Einstein's mistakes inadvertently brought an unsolved mystery to the world. Xu Mang said solemnly: "The cosmological constant is given a physical equivalent to vacuum energy, that is, the background energy that exists in space, that is, dark energy. ”

afterwards

Xu Mang was out of control.

From the speculation of dark matter to the overturning of the theory of the Great Collapse, from the problem of cosmological constants to the theory of quantum gravity, from the assumption that the vacuum has force properties to the theory of inflation.

Xu Mang is going farther and farther on the road of pretending to be forced,

Don't look back.

And the scene gradually began to get out of control.

“...”

“...”

“...”

Is there an end?

Is there an end?

You're standing on it and not coming down, are you?

The classmates were going crazy, and in addition to marveling at Xu Mang's knowledge, they felt that this was a large-scale pretending scene, and he had become an innocent background board behind Xu Mang's pretending.

A simple cosmological constant, actually involves so many things, and even some theories are unheard of, such as the extremely nonsense theory of the great tear of the universe, 90 billion years later, you say a yarn!

At this point,

Xu Mang is talking about quantum field theory in curved space-time, a concept used to prove the thermal radiation of black holes proposed by Professor Hawking, that is, Hawking radiation.

But the students turned their attention to the professor, hoping that he would stop this large-scale coercive scene.

Pity...

The professor was very interested in Xu Mang's opinion, and he was listening to it with fascination.

For a full hour and a half,

It wasn't until Xu Mang spoke on stage that his mouth was dry, and he realized that he was out of class.

"Ahem!"

"Professor... My voice was hoarse. Xu Mang looked at the professor on the side and said helplessly, "Can you get out of class?"

"Class!"

Suddenly,

All the students fled the scene one after another, for fear that they would be caught by Xu Mang too late.

Just when Xu Mang was holding the physics book and preparing to go to the sophomore classroom of the optics major, he was caught by the professor.

"Xu Mang?"

"When did you secretly learn astrophysics?" the professor asked curiously, "It seems to be good, very good." ”

"When dreaming. Xu Mang said with a grin.

“...”

"Don't make trouble in front of me, otherwise you will have to retake this compulsory course for me, you know?" the professor said helplessly with a dark face.

I'll go!

This is really a teacher all over the world, isn't this my way of threatening optics students?

"What..."

"Professor, your surname?" asked Xu Mang curiously.

“...”

"It's November!" The professor looked at Xu Mang and said seriously, "Two months have passed, and you can't remember my name?"

"Uh..."

"It's really raining and I don't have anything to do. Xu Mang said: "I didn't take much class in the past two months, and I was either arrested by this one as a coolie or that one was arrested as a laborer. ”

Hearing Xu Mang's complaint, the professor smiled and said silently: "I'm very interested in your light pressure conjecture, you said that light pressure may cause accelerated expansion in our four-dimensional universe, what is your point of view?"

"I'm talking nonsense..."

"Fooling my classmates. Xu Mang didn't know why the system gave the light pressure conjecture, and then said: "It may be because when the gravitational force of the star is less than the light pressure, the star will expand, and when the gravitational force is equal to the light pressure, the star will be in a stable state, and from this point of view, it can be deduced that the light pressure is related to dark matter." ”

Oh?

It's kind of interesting!

This is a very bold guess.

The professor was about to speak, when Xu Mang hurriedly said, "Professor, I'm going to give a lecture... It's too late!"

Words fall,

Xu Mang ran away directly.

Looking at this back, an idea popped up for the professor.

...

"Academician Fang. ”

"Xu Mang's physics level is very high!" The professor found Director Fang of the Department of Physics and said with a serious face: "I can't let Xu Mang run around anymore, this is simply a waste of his talent!"

Director Fang is confused, Xu Mang's physical level is very high?

No kidding, right?

"Professor Zhong!"

"Are you sure Xu Mang's level of physics is very high?" Director Fang asked in disbelief, "You said it shouldn't be optics, right?"

"No, no, no!"

"He is very good at relativity, quantum mechanics and astrophysics!" the professor said earnestly, "and today he gave me a great surprise, and although he was full of nonsense, I was surprised by some bold ideas. ”

"What?"

"What did this kid do?" asked Director Fang.

"I asked him to explain the cosmological constant, and it took him an hour and a half to pull me out a whole bunch of stuff. The professor laughed, "The details are outrageous, and he even knows some of them that I haven't touched." ”

This...

Is this possible?

When Director Fang heard the professor's words, he immediately fell into doubt, two and a half hours ago he was an idiot who didn't know anything about physics, and now he suddenly turned into a genius who crushed university professors.

"Professor Zhong!"

"Are you sure he's not talking nonsense?" Director Fang asked, "The level that Xu Mang showed in theoretical physics before was simply miserable. ”

"I wonder too!"

"I inquired, except for the first few days of school, Xu Mang listened carefully to the lectures and took notes carefully, and he could hardly afford to lie down for the rest of the time. The professor was also full of doubts: "Why is it so powerful all of a sudden?"

Time

The two were in a state of confusion.

ultimately

Director Fang decided to test Xu Mang separately and produce a very comprehensive test paper, including relativity, quantum mechanics, optics, solid state electronism, macroscopic quantum states and so on.

"Academician Fang. ”

"Who produced this volume?" the professor asked.

"I'm here myself!"

......