It's not that hard,

If Xu Mang finds it difficult, it is quite difficult to expand a simple problem into such a complex one... I almost didn't faint, who is the problem?

I want to kill him.

As soon as the words fell,

Tong Min and Lu Bo looked at Xu Mang in surprise, he... He just said that it is not difficult?

"Xiao Xu?"

"You... Are you sure it's not difficult?" Tong Min asked with a surprised face, "Take a closer look... Maybe you may be mistaken, this topic is not as simple as you think, from frequency to volume expansion, this... That's a lot of calculations, aren't you sure it's that hard?"

"Really?"

"I think it's okay..."Xu Mang said with a smile, "Do you have paper and pen?"

"Yes, yes!"

Lu Bo hurriedly took out the same black pen and handed it to Xu Mang, and by the way, handed over a writing board with a number of manuscript papers on it.

After getting the pen and paper,

Xu Mang began his own performance, but this time he planned to write slowly, pointing out the mistakes of these people while doing the calculations.

"Look..."

"According to the photon, i.e. when V to dv, the volume expands to V(t), so the calculation process is like this..."Xu Mang wrote a very complex calculation process, but as he continued to simplify, this complex calculation gradually became easier.

"If T(t)=R(t)T(t)/R(t), you can still get the distribution of the blackbody spectrum..." Xu Mang wrote the equation on the white paper lightly, but at this moment, the atmosphere of the scene condensed to the freezing point.

Tong Min, Lu Bo, Liu Yan and Zhao Pengpeng couldn't imagine what was happening in front of them, and the problem of stumping themselves for more than half an hour had become so simple in the hands of this stranger.

This... Is this in a fantasy world?

A world of dreams?

How could it be otherwise!

From an extremely complex calculation process, with continuous simplification, gradually clearing the fog and revealing its appearance, this moment... The four people present felt that they were about to suffocate, especially Liu Yan, a graduate student from the Department of Mathematics.

though

It's all about the calculation process of physics, but the process of every step of his transformation from complex to simple makes Liu Yan unable to believe her eyes, sure that this guy is studying physics, not majoring in mathematics?

This math ability...

It seems to be about the same as his own professor.

While the four of them were still in shock, Xu Mang had already completed his proof of the time relationship between the distribution of heat equilibrium and the dependence on temperature, and the whole process was as smooth as flowing water, without the slightest hesitation.

"It's done..."

Xu Mang smiled and asked, "Is there anything you don't understand?"

“...”

“...”

“...”

The four of them were silent, shocked by Xu Mang's strong strength.

"Xiao Xu?"

"Who the hell are you?" Tong Min raised his head and looked at Xu Mang seriously: "You... Are you really a former college student? You can't be an ET, right?"

"Have you ever seen such a handsome ET?" Xu Mang said angrily: "You are allowed to have an opinion on me, but please don't question my appearance, Shengshi is beautiful... No kidding, I have a nickname at Fuda - Fangxin Arsonist, do you know what it means?"

"The man who set fire to a woman's heart..."Xu Mang sighed, glanced at Yang Xiaoman, and said helplessly: "I don't want to bear such a title either... It's a pity that this is fate, and it can't be changed. ”

“？？？”

“？？？”

“？？？”

Good narcissism,

What a beating!

This guy... You can't be a madman, right?

"Ahem!"

"I said... Xiao Xu handsome guy?" Zhao Pengpeng smiled bitterly and said: "Mr. Fangxin arsonist, can you solve the third problem? If the gas above is replaced by a particle gas with no interaction but mass, and it is in thermal equilibrium at the beginning, under the influence of the expansion of the universe, is it in thermal equilibrium?"

Words fall,

Four eyes shone on Xu Mang, and the four of them were looking forward to Xu Mang's answer.

Faced with this question, I don't know what kind of explanation this mysterious Xiao Xu will make, whether it is the same as the previous two questions, the answer will be obtained in an instant, or the myth will be terminated.

Xu Mang didn't look at the topic, the third question and the second question are interrelated, since the second problem is solved, the third question is as simple as probing for things.

"Anyway..."

"Have you been tricked?" Xu Mang asked curiously, "These questions... It shouldn't be solved by graduate students like you, it involves a lot of concepts, and the second and third questions are cosmological inferences based on the theory of heat death, the second law of thermodynamics, starting from this core. ”

"You..."

"What is the name of the professor who provides this kind of question?" Xu Mang asked.

Hearing Xu Mang's words, Tong Min and Lu Bo's expressions were full of the word calm, and Tong Min said, "Professor Simpudi... He is an expert in astrophysics and an alternate member of the Princeton Astrophysical Society. ”

Xu Mang: ???

What?

Alternates?

Reserve?

For the first time, Xu Mang heard that the research organization he was in still had so-called reservists.

"Is this guy discriminating against Huaguo?" Xu Mang asked curiously: "From your point of view, I feel the malice from the questioner, this is deliberately embarrassing you, with your limited level, it is impossible to solve such a complex cosmological problem." ”

Xu Mang's words made the four of them feel unconvinced, the graduate students of the Ivy League actually became a limited level in his eyes?

Truly...

Xiao Xu is very powerful, but... You can't be so arrogant, can you?

This is a relativistic cosmology problem, and Xiao Xu is engaged in relativity, although... There are some differences, but after all, it is a system, and I understand it more or less.

"Yes!"

"He famously said... Rather admit black and white than Asian students. Tong Min said: "Lu Bo and I are exceptions, the results are too good... Had to teach. ”

Xu Mang nodded and said indifferently: "I'll help you solve the third problem first." ”

Words fall,

Xu Mang began to solve this problem, in fact, this malicious professor still has a little conscience, in the concept of difficulty, Xu Mang proposed a level division, which are ordinary, nightmare, hell and death, these four difficulty levels, but... There is a difficulty that transcends cognitive concepts.

It's called Xu Mang...

As far as these three problems are concerned, they have only reached the level of nightmares.

"Actually..."

To solve this problem, we first need to calculate the number of particles with momentum between p and p+dp in thermal equilibrium under the ideal gas approximation. Xu Mang wrote about the calculation process and explained it lightly.

"where the E chemical potential makes it equal to zero, and since the expansion of the particle is adiabatic, TV^r-1 = constant. Xu Mang raised his head, glanced at the four of them, and said, "The existing thermal balance will be destroyed." ”

This...

And that's the end of it?

Join... Not even thirty seconds!

"Little... Xiao Xu?"

"Solved?" Tong Min asked in surprise.

"That's right!"

"It's not a big deal in itself. Xu Mang smiled and said: "There are some conceptual knowledge in it, you don't know much about it... It's normal, but for me it's just a matter of getting your hands dirty, just sweep it with the whites of your eyes. ”

The four of them didn't speak, staring at Xu Mang silently, this guy... It's getting more and more mysterious, he looks very young, although he wears glasses, but the overall silhouette of this... Déjà vu.

"The last question, solved... I went to grill the skewers. Xu Mang shrugged his shoulders and said lazily, "Let me take a look first..."

moment

Xu Mang began to solve this last problem, which is still a hypothetical universe, but this condition is more extreme, photon gases do not interact with each other, and the mass is zero, while particle gases are composed of mass m, and at a certain moment photons and neutrinos are in the same thermal equilibrium state.

And then... The typical velocity and kinetic energy are given with neutrino mass m.

It's not hard!

But it's cheap!

When Xu Mang saw the last request, he was almost not angry, and the difficulty was suddenly raised from the nightmare level to the death level.

The professor asked for a fairly precise number.

Crazy, right?

Xu Mang's original decadent state disappeared at once, and his face was full of seriousness at this time.

it!

Ruthless!

This... It really doesn't seem like it's going to be solved for a while.

Just when Xu Mang was thinking about how to start, Tong Min and Lu Bo's hearts almost rose to their throats, and the two saw that Xu Mang's expressions had changed, no longer as calm as before, but a little serious.

Finished!

It doesn't feel good!

Sure enough, the problem of the finale is different.

The two glanced at each other, and both saw a trace of worry in each other's eyes, the first three problems were solved perfectly, and the result... Fell on the last question.

Alas...

seemingly

The miracle ended.

"Xiao Xu?"

"No, forget it... It's good enough to be able to solve three questions, I think... The professor won't be embarrassed by this. Tong Min said seriously: "The last question he told us, no matter who we find, as long as we solve it... Let's graduate, you can imagine how difficult it is. ”

Xu Mang was stunned for a moment, and asked curiously, "So rampant?"

“？？？”

“？？？”

“？？？”

Hearing Xu Mang's words, the four of them looked confused.

What do you mean?

As if you're better than him... It's even more rampant!

"Xiao Xu!"

"It's not about being rampant, it's... How can I explain it to you. Tong Min said helplessly: "It's the meaning of no solution... He didn't give us any chance at all, and this last question was just decoration, just take a look. ”

Xu Mang understood what he meant, that is, he deliberately made it bad.

But...

This problem is not unsolvable, but it is more complex to argue and computationally challenging.

truly

Let these two graduate students in astrophysics solve it, the difficulty is a little higher, but unfortunately I met the beauty of Ben Shengshi, I can only say sorry to the professor who is full of malice, these two students are afraid that they will graduate early.

"Huh?"

"Do you inherit the family business after graduation, or do you plan to pursue academic research in astrophysics?" asked Xu Mang curiously.

"If you're inheriting the family business... I went to business school. Tong Min said seriously: "If you graduate successfully next year... I plan to pursue a career in astrophysics. ”

"Same. ”

"Engaged in academic research in astrophysics. Lubo said.

Xu Mang glanced at the two of them and fell into silence.

Long

Xu Mang said apologetically: "I'm sorry... I'm afraid I'm going to disappoint you. ”

......

Wonderful Book House