1900: A physics genius wandering around Europe

Chapter 571 The third beast! Maxwell's demon! Breaking the heat death! Reversing time and space! Who can kill it?
The so-called "heat death" specifically refers to the hypothesis of the ultimate fate of the universe derived from the second law of thermodynamics.

According to the law of increasing entropy, all energy in the universe will be converted into heat energy, so that matter will not have any macroscopic movement and reach a state of thermal equilibrium.

Heat is not a substance but a dynamic form of mechanical action.

If there is no mechanical motion, there is no heat.

Therefore, matter still exists in a heat-death universe.

It's just that they are like photographs, frozen in time and will never change again.

This is very different from the end of the universe deduced from the Big Bang theory.

The big crunch ending in the Big Bang at least offers a chance to start over, but heat death means eternal loneliness.

Therefore, many physicists at the time could not accept this fate.

Maxwell was one of them.

As one of the founders of the law of increasing entropy, he actually questioned this theory.

It can be seen that the fate of heat death brings shock to everyone.

At this moment, Li Qiwei continued:

"So, how does Maxwell overturn the second law of thermodynamics, or the law of increasing entropy?"

"He proposed a thought experiment, and this is how it works."

"Suppose there is a container divided into two parts, A and B, on the left and right."

"There's a partition between A and B."

"Normally, molecules in A cannot move into B, and molecules in B cannot move into A."

"However, the molecules in AB will hit the partition due to thermal motion."

"At this point, Maxwell assumed there was a gremlin."

"It has an amazing ability to tell at a glance how fast individual molecules are moving."

"So, Xiao Yao opened a small hole with a switch in the partition."

"When the faster molecule in A hits the partition, the demon opens the hole and allows the molecule to enter B."

"Otherwise, it continues to close the hole, allowing the slower molecule to remain in A."

"Similarly, when the slower molecule in B hits the partition, the demon opens the small hole and allows the molecule to enter A."

"On the contrary, it continues to close the hole, allowing the faster molecule to remain in B."

"After a long time, A is full of slower molecules, and B is full of faster molecules."

"We know that the essence of temperature is the random motion of molecules."

"The faster the movement, the higher the temperature."

"Thus, a temperature difference is created on both sides of the container, and work can be done externally."

"After the energy is consumed, Xiao Yao will continue the previous operation."

"This cycle repeats itself over and over again. This is a viable perpetual motion machine model."

"First of all, this perpetual motion machine does not violate the first law - the law of conservation of energy."

"Because the little demon didn't [exert influence] on any molecules."

"It just allows molecules moving at different speeds to go into different areas."

"And the molecules enter by their own motion."

"Then, this perpetual motion machine does not violate the Second Law."

"The demon did not consume any extra energy, but transferred the heat from the low-temperature area A to the high-temperature area B."

“And, in the process, it also reduces the overall entropy of the system.”

"According to the entropy formula of microscopic system given by Boltzmann: S=klnΩ."

"S represents the entropy of the system, k is a constant, and Ω is the number of microstates of the system."

"In the original system, the speeds of the molecules in A and B were irregular."

"After Xiao Yao's operation, there are only slow molecules in A and only fast molecules in B."

"Obviously, the number of microscopic states of the system decreases, so the total entropy of the system decreases."

"In this way, Xiao Yao has broken the law of increasing entropy."

"If we extend the Little Demon to the entire universe."

"Such a sharp-eyed little demon also exists in our universe."

"It tirelessly splits the molecules in the universe into two parts according to their speed."

"Then the universe will not fall into the tragic end of heat death."

"This is the famous Maxwell's Demon."

"Maxwell placed a restriction on the Second Law of Thermodynamics:"

"The second law of thermodynamics holds true only if we can deal with bulk matter, not the molecules that make it up."

Wow!
Most people looked shocked.

Before today, they didn't know that there was such an incredible conjecture in thermodynamics.

"Oh my God! Doesn't that mean the second theorem is broken?"

"I feel like there's nothing wrong with Maxwell's demon."

"Neither the First Law nor the Second Law is violated."

"But the end result defies the Second Law."

"This is amazing!"

Maxwell is indeed a great figure who can be ranked alongside Newton.

Although his main achievement was the unification of electricity and magnetism.

However, he also achieved remarkable results in thermodynamics, and even proposed such a fantastic conjecture as Maxwell's demon.

Break the heat death and reverse time and space!

Pull the universe out of the ruins of chaos and restore order!

For a time, everyone was talking about it.

Someone asked curiously:
"Professor Bruce, has Maxwell's demon been disproven, just like Laplace's beast?"

Li Qiwei shook his head and said:
"So far, there is no convincing evidence that Maxwell's demon is wrong."

Wow!
Everyone was shocked again!

It has been about 60 years since Maxwell's demon was proposed, but it has not been solved yet?
Classical physics indeed still has many treasures waiting to be discovered.

Lang Zhiwan and others smiled bitterly.

Don’t be fooled by the rapid development of relativity and quantum mechanics, which have completely overturned the foundations of physics.

But thermodynamics is a school of its own and is not to be disturbed.

Even quantum mechanics cannot solve the ultimate problem of thermodynamics.

In later generations, some people even wanted to incorporate gravity into thermodynamics and reinterpret gravity from the perspective of thermodynamics.

I have to say, this idea is unique.

At this time, Wang Dezhao, who had been thinking, suddenly asked:
"Professor, I have a question."

"When the Maxwell demon opens and closes the small hole, it is equivalent to doing work on the system, which will inevitably consume the heat energy in the system."

"In this case, the work that can be generated by the next heat flow must be less than the previous one."

"After a limited number of times, the heat in the entire system will inevitably be consumed."

"Does this prove that it violates the Second Law?"

Wow!
All the students were shocked!
The conjecture proposed by super boss Maxwell has not been solved by anyone for decades.

Wang Dezhao actually wanted to find the mistake?

Everyone admires him very much!
This is the Olympic master!
Everyone thought about Wang Dezhao's doubts and found that it was indeed a problem.

Isn't opening and closing the hole an additional work on the system?

Li Qiwei was slightly stunned when he heard this, and then he smiled with relief.

He was very satisfied with Wang Dezhao's performance.

So, he smiled and said:

"Yes, you are very observant."

"The little demon and the container are one and the same, they belong to the same system."

"Although the little demon uses mechanical energy to open and close the cave, it consumes the heat energy of the entire system."

"But Maxwell himself gave an explanation."

"The reason why he called this manager a "demon" was to highlight its uniqueness."

"You can think of the little demon as almost non-existent, and the door at the entrance of the cave has almost no energy."

"Therefore, the little demon does no work when opening and closing the cave entrance."

Wow!
Everyone was confused. Why did it feel like Maxwell was being naughty?

How could such a little demon exist in reality?

Its ability is a bit too incredible.

Not only can it track the position of each molecule, but it can also discern the speed of each molecule.

Most importantly, none of these processes consume energy.

It’s outrageous to think about.

However, since they are all monsters, it is normal to have some "magic power".

At least these functions do not currently violate the definition of matter and energy.

And since it is just a conjecture, there will definitely be some extreme conditions.

If you want to overthrow Maxwell's demon, you must prove theoretically that the demon must consume energy.

That is: the ability of Maxwell's demon is impossible to achieve!

At least so far, no one has been able to do it.

In real history, although physicists saw the problem of the demon doing work, they could not refute this setting theoretically.

Wang Dezhao seemed to be thinking about something when he heard this.

He actually did not approve or oppose the tendency of Maxwell's demon.

Instead, think of it as a mind exercise.

If you agree with this hypothesis, how can you prove it?

If we oppose this hypothesis, how can we prove it?

Wang Dezhao suddenly found that his mind seemed to be opened.

He began to really think about a proposition like a physicist.

Instead of working backwards once you know the answer.

"One lecture by Professor Li is worth a year's worth of my classes."

Wang Dezhao's questions sparked the interest of other students.

Everyone asked questions.

The second law of thermodynamics has been verified by countless experiments, and its correctness cannot be easily overturned.

Therefore, in everyone's mind, Maxwell's demon is most likely wrong and violates the second law.

But no one could find the mistake.

At this time, Oppenheimer, who had been silent all the time, suddenly asked:

"Professor, how do we understand the [measurement behavior] of Maxwell's demon?"

"According to the description of the conjecture, Xiao Yao should be able to know the movement speed of molecules in real time."

“But how does it accomplish this?”

"In the macroscopic world, if we want to know the speed of an object, we have to measure it."

"And whenever there is measurement, energy is lost."

“Otherwise the measurement cannot be done.”

"Therefore, if Xiao Yao wants to know the movement of each molecule, he must consume energy."

"In this case, Maxwell's demon does not actually violate the second law."

Wow!
Everyone was shocked when they heard this!
This is a very reasonable explanation.

In the real world, if you want to know the speed of an object, you have to at least use something to measure it.

For example, when you use a ruler to measure your height, both the “holding process” and the “measuring process” consume energy.

To measure the speed of a car, you can have one person stand at the starting point and the end point and record the time taken.

And the person at the starting point must tell the end point that the timing has begun.

If messages were sent by telegraph, this would also consume energy.

In short, the “act of measurement” itself consumes energy.

The energy required to measure Maxwell's demon is greater than the energy required to reduce the entropy of the system.

Everyone felt as if something had suddenly become clear.

"This dude is awesome!"

"Boss He!"

"Is he going to put an end to Maxwell's demon today?"

"Shit, if this succeeds, he still has the chance to compete in a Mao competition!"

"The uncrowned king."

For a while, everyone was asking each other about Oppenheimer's personal information.

However, before Li Qiwei could answer, Wang Dezhao next to Oppenheimer spoke first.

"Brother Ao, I think your point of view is wrong."

"Maxwell's demon doesn't need to measure the exact value of the molecule."

“It just has to figure out which molecule is faster.”

"And this judgment process does not require energy."

"For example, if two cars are moving in the same direction, we can tell at a glance which car is moving faster."

"This process does not require measuring the specific speed of the car."

"Since Maxwell's demon is a virtual entity, it should be easy for it to make such a judgment."

Wow!
This time, everyone was simply stunned!

No one expected that Wang Dezhao had completely cracked Oppenheimer's answer without even Professor Bruce's help.

Oppenheimer's eyes lit up when he heard this.

He looked at Wang Dezhao and the two began to debate.

"When the human eye is looking, the light reflected by the car enters the eye and is then processed into a picture, which also consumes energy."

[Since Maxwell's demon has such incredible abilities, it is not surprising that it also has a special sensory organ that surpasses humans. ]

"."

The two of them interacted with each other, making the show very exciting.

In the end, neither of them convinced the other.

However, their eyes were filled with admiration, not disgust.

Heroes appreciate each other!

Bigwigs like Lang Zhiwan and de Broglie also nodded slightly.

Although the physics community currently generally agrees that Maxwell's demon is wrong.

But if we cannot prove it strictly, we cannot make a judgment.

Therefore, these big guys were just thinking but not speaking.

At this moment, a brave student asked directly:
"Professor Bruce, do you think Maxwell's demon is right or wrong?"

Wow!
The venue fell silent instantly.

Everyone looked at the stage eagerly.

Geniuses such as Oppenheimer and Wang Dezhao opened their eyes wide.

Professor Bruce said before his speech that he wanted to bring new inspiration to everyone.

That must be a level higher than what they just discussed.

Even Lang Zhiwan and others looked excited.

"Is Professor Bruce going to subvert again?"

Li Qiwei looked at everyone, then smiled slightly and said:

"I do have some immature thoughts on this issue."

"I think that Maxwell's demon should not be thought of in terms of matter or energy."

Everyone was stunned!
The second law of thermodynamics is about the relationship between matter and energy.

Without matter and energy, what is left of physics?
From what angles can we consider it?

Li Qiwei said calmly:

"information!"

Wow!
The whole audience was shocked!

information?

(End of this chapter)