1900: A physics genius wandering around Europe

Chapter 573: Information Theory Sword Kills Maxwell's Demon! The Audience is Shocked! Is there a Fourth Divine Beast?

When the concept of information entropy came out, everyone was shocked.

"What a fantastic idea!"

Compare information to the system in thermodynamics and study the nature of information from the perspective of entropy.

For a time, everyone was talking about it.

"Professor Bruce's thinking is so advanced!"

"Information is such an ethereal existence, can it be studied using physics methods?"

"So, is information also a physical entity?"

Someone retorted:
"Probably not."

“Currently, there is no theory or experiment to prove that information is a physical entity like atoms.”

"The information entropy defined by Professor Bruce is a thermodynamic method to study information."

"But there is one thing I don't understand: what physical quantity should be used to study the specific properties of information?"

"Speed? Energy? Displacement?"

“Does information have these physical parameters?”

"In addition to entropy, thermodynamic systems also have parameters such as energy, temperature, and pressure."

"Only entropy can't describe the information system."

Many people nodded in agreement.

Information is indeed a form of existence that is completely different from matter and energy.

At this time, Li Qiwei continued:

"In order to better discuss the nature of information, it is necessary to limit the scope of information."

“When I say information, I mean information that can be stored in electronic or digital form.”

"for example."

“I want to store the word [speech] in the machine.”

“The speech contains 6 letters, so I define its information entropy as 6.”

"The information entropy here refers to the complexity of the letters that make up the word speech, not the amount of information it can map."

"Because you can definitely say that when you see the word speech, you think of the contents of many speeches."

"Then we cannot estimate the true amount of information in speech."

“Even the amount of information each person can get from a speech is different.”

"In the field of communications, information entropy is a concept for coding machines, not an extension of human perceptual thinking."

“So, long words simply contain more information than short words.”

“That’s why when people send telegrams, the more words they have, the more expensive it is.”

"For you, one sentence and ten sentences may convey the same amount of information."

"But for a telegraph machine, it can only follow mechanical and mathematical principles and send one word at a time."

Everyone nodded silently.

They accepted this setting easily.

This is a common method in scientific research.

That is to focus on the main issues for analysis. There is no need to directly study the complex situations in the real world.

Once the theory is mature, it will be gradually applied to more complex scenarios.

For example, quantum mechanics begins with the study of the properties of electrons and is then extended to all microscopic particles and systems composed of particles.

“I said before that we should re-examine the Maxwell demon problem from the perspective of information.”

"But the question is, how does information connect to the physical world?"

"Information is, after all, ethereal."

"An atom is moving there, it has speed, position, energy, etc."

"If we write down these parameter values ​​on paper, then we have information about the atom."

"But if we burn the paper now, will the information still exist?"

Everyone was talking about it.

This is a very interesting question.

"Obviously, for the atoms themselves, the information is not lost."

“It still has the same parameters of speed, position, energy, etc.”

"Just because a piece of paper is burned doesn't mean that the information on it disappears."

“But for researchers like us, the information is literally lost.”

“So, there is a key issue involved here.”

“Will changes in information affect changes in the physical world?”

“In other words, can we build a bridge between the information and physical worlds?”

Everyone was shocked!
They followed Professor Bruce's ideas and thought about the problem more and more deeply.

Is information a ghost or some kind of existence?
At this time, Li Qiwei was full of confidence, which shocked everyone!
"I think it's possible!"

"The answer lies in the two parameters of entropy and energy!"

“The objective world is composed of matter and energy, and according to the mass-energy equation, matter and energy are two sides of the same coin.”

"So if we can find the relationship between information entropy and energy, we can connect information to the physical world."

"So, how do you do it?"

"I just mentioned that Clausius reformulated the second law of thermodynamics in terms of entropy."

"In the formula he gave, the entropy and energy of the system satisfy a specific relationship."

"Then, Boltzmann defined the relationship between entropy and energy in more detail from a microscopic perspective."

“Here, I make a bold assumption!”

“Thermodynamic entropy and information entropy are not distinct but deeply connected.”

"In the field of communications, any information requires a physical carrier."

"Information and energy act through these real substances."

"When we process information, we must also operate on these physical carriers at the same time."

“While the information itself doesn’t obey the laws of physics, these physical carriers do.”

"So, these physical carriers must also obey the laws of thermodynamics."

"In this way, information entropy and energy can be linked through thermodynamic entropy."

Amid the shock and confusion of the crowd, Li Qiwei continued:
"for example."

"The principle of the telegraph is to use the presence or absence of electric current to represent different information."

"In binary telegraphy, the presence of an electric current is considered a 1, and the absence of an electric current is considered a 0."

"Through the combination of 0 and 1, various letters, numbers, and symbols can be encoded to convey complex information."

"The telegraph operator first encodes the information to be sent into electric current information according to a specific rule, such as Morse code."

"These currents are then transferred through the wire to the other end at the speed of light."

"At the receiving end, these current signals affect the typewriter device through the principle of electromagnetic induction, and the electrical signals are restored into human-readable text information."

"It can be seen that whether at the sending end or the receiving end, information is transmitted using the real physical existence of electric current as a carrier."

"And the electric current itself is consistent with various known physical theories, such as electromagnetic induction."

"So if we modify the information, we are actually modifying the current."

"And when the electric current is changed, its interaction with matter must also change."

"In other words, it seems that we have only changed the information itself, but because information needs a physical carrier, the physical carrier must obey the laws of physics."

"So, indirectly, we changed the physical world again."

"And this is the relationship between information and the physical world!"

"Based on these analyses, I propose the following conjecture about the relationship between information entropy, thermodynamic entropy, and energy." "Any logically irreversible information operation process, such as erasing a unit of information, will be accompanied by an increase in the thermodynamic entropy of the information processing device or its environment, thereby consuming energy."

"For example, in a telegraph machine, if you want to delete some information, you must operate the machine and change its current law."

"In this process, the machine consumes more energy, thus causing a greater change in thermodynamic entropy."

"This can be calculated based on the Boltzmann entropy formula and the Clausius entropy formula."

Wow!
The venue suddenly became quiet!
Immediately afterwards, a burst of exclamations broke out!
Everyone widened their eyes, shocked!
Professor Bruce has confined the ghostly existence of information into the real world simply through logic.

This is incredible!
"My goodness!"

"Erasing information causes the entropy of the environment to increase?"

“I can’t even imagine this process.”

"Professor Bruce actually deduced it rigorously?"

"This is too exaggerated!"

"."

After hearing this, some people were even more confused.

"So, who can tell me what that information is?"

“Is it also a kind of matter or energy?”

"Otherwise, why would it affect energy?"

Everyone shook their heads.

They cannot understand the relationship between information and the material world.

In other words, the conjecture just proposed by Professor Bruce is the relationship between them.

Bigwigs like Lang Zhiwan and de Broglie were also shocked.

This angle is so clear!

Lang Zhiwan sighed:

"Unintentionally, Professor Bruce has opened up a whole new theory."

"This theory specifically uses mathematical and physical methods to study information. Perhaps it will be called information theory in the future."

De Broglie said:

“I feel that information theory is more of an engineering theory.”

“The examples Professor Bruce cited were all in the communications field.”

“At least for the time being, I think information theory will have little impact on existing physics.”

The other bosses nodded, obviously agreeing with this judgment.

After all, this is the problem that Professor Bruce discovered from communications engineers, and it also solves the definition of information in the communications field.

If we put it into the field of physics, I'm afraid no one can tell clearly how much information an atom contains.

But even so, information theory is a wild conjecture that will surely cause a stir in the academic community!

At this time, Li Qiwei continued:

"Now that we have a hypothesis about the relationship between information and energy, we can analyze Maxwell's demon from the perspective of information."

Wow!
Everyone instantly focused.

The main event is finally here!
"The demon can tell the speed of a molecule with just one look. We make the extreme assumption that the process of looking does not consume energy."

"But the speed of a molecule is a kind of information."

"Suppose the demon uses a memory device to store the molecular speed information it measured."

"The little demon must store this information first before deciding whether to open the cave."

"So, Xiao Yao is actually increasing the amount of information in the system."

"According to the previous analysis, this increase in information will lead to an increase in thermodynamic entropy."

"Therefore, the absolute value of the entropy reduction caused by the demon by separating molecules of different speeds is less than the absolute value of the entropy increase caused by the increase in information."

"When the two are added together, the entropy of the system still increases, so the second law of thermodynamics is not violated."

"At this point, some people may have questions."

"Then after Xiao Yao records the information of the molecule, can't he just delete it?"

"But erasing information also requires dissipating system energy, which increases entropy."

"That's the conjecture I just proposed."

At this time, someone asked:
"Professor, can we make Xiao Yao's storage infinitely large without deleting it?"

Li Qiwei said:
"Maxwell's demon is a conjecture that describes the real world."

"Even the universe is finite, so there can't be an infinite physical concept."

"Therefore, any memory must also have limited resources, and Xiao Yao must constantly erase previous information."

"Otherwise the separation process can't continue."

"And in this process, the little demon has been increasing the entropy of the system."

"In short, the increase in entropy caused by information erasure must be greater than the decrease in entropy caused by gas separation."

"Thereby ensuring that the second law of thermodynamics is not violated."

“That’s my explanation.”

boom!
The whole audience was shocked!

Everyone had an incredible expression on their face.

"Oh my god! This is so exciting!"

"The explanation of Maxwell's demon from the perspective of information is absolutely impeccable!"

"So, this beast has been dealt with by Professor Bruce?"

Someone said:

"It's still too early to say for sure, because Professor Bruce's theory still needs to be verified experimentally."

"But I can't figure out how to experiment with the process of erasing information."

"I can only say that Professor Bruce's theory is really too advanced."

Everyone worshipped him!

In order to explain Maxwell's demon, Professor Bruce actually invented a new theory.

This kind of strength is simply unstoppable!
Oppenheimer, Anderson, Wang Dezhao and others had fanatical looks in their eyes.

This is the perfect image of a physicist in their minds.

When all physicists were at their wits' end, the other party suddenly opened up a new path.

Let’s not talk about how correct information theory is.

This new field itself is of infinite value.

Humans have had the means to use information since a long time ago.

However, it was not until today that Professor Bruce summarized and studied it from a theoretical perspective.

It can even explain shocking conjectures such as Maxwell's demon.

powerful!
too strong!
Looking at everyone's shocked expressions, Li Qiwei smiled slightly.

He encouraged the young people in front of him.

“Even if some of these conjectures put forward by our ancestors are wrong, they are still full of value.”

"They are not proposed for argument, but to explore the boundaries and limits of physics."

“So, all of you here should also be good at thinking and asking questions.”

"Classical physics has three conjectures about the three beasts, but what about modern physics?"

"I believe that someone will come up with a conjecture about relativity and quantum mechanics in the future."

“By then, maybe I’ll become one of the four great beasts of physics.”

The students' eyes were burning with excitement!
After a bowl of chicken soup, they are full of fighting spirit!

(End of this chapter)