94: From Technological Warfare to Space Empire

Chapter 119 Maxwell's Demon (20,000 words today! Requesting monthly votes!)

After Lin Yu finished speaking, the last part finally arrived.

When he bowed, he was still trembling slightly.

Fortunately, he had already put on a show in front of top experts like academicians.

Now, even when I'm in front of a group of Tsinghua University graduates, I can confidently talk about my research in theoretical physics without feeling too nervous.

But he knew this was far from over.

The questions from the crowd that followed were the real test for him.

The applause lasted for a full five minutes.

Lin Yu stood on the podium, feeling a little embarrassed by the applause.

He raised his hand several times, trying to signal everyone to stop.

But every time he raised his hand, the applause became even more enthusiastic.

In the end, it was Academician Wang who came over to smooth things over for him.

Academician Wang stood up, turned around, and waved to the students.

"Alright, alright, your hands will swell up if you keep filming."

Laughter gradually filled the classroom, and it took a long time for it to subside.

But no one got up to leave, and no one rushed to the cafeteria to grab food.

Everyone remained seated, their eyes fixed intently on the young man in the white shirt on the stage.

Their purpose is clear.

Lin Yu is talking about the very cutting edge of the cutting edge.

Those of them who want to pursue academic research cannot possibly be unaware of this.

Whether it's a vacuum cavity or a light trap.

In fact, even laser cooling technology is a new technology from 10 years ago.

In this era before even the internet existed.

The books did not spread quickly.

They have almost no access to learn or understand this kind of knowledge.

Lin Yu's story unfolded before my eyes.

They wished they could put Lin Yu on the podium and lecture him for three days and three nights.

Lin Yu felt a little uneasy under that gaze and subconsciously touched his nose.

"So—does anyone have any further questions?"

As soon as he finished speaking, dozens of hands shot up in unison.

Lin Yu paused for a moment, then smiled.

"Okay, let's chat a little longer then."

He randomly picked an elderly gentleman in the first row.

The old man stood up, adjusted his glasses, and said in a hoarse voice.

"Comrade Lin, I'm from the Materials Science Department, my surname is Chen."

"I have a question about the evaporation and cooling process you just described."

"Please speak!"

"Using radio frequency fields to kick out high-energy atoms is a great idea."

"But how can we ensure that we only kick away the hot ones and avoid the cold ones?"

How do I choose the frequency for the radio frequency field?

"It can't be done. Isn't this just another Maxwell-esque thought experiment?"

Maxwell's Demon, one of the so-called four great demons of physics.

Maxwell realized, based on the second law of thermodynamics, that there exists an energy control mechanism in nature that counteracts the increase of entropy.

But he simply couldn't explain the structure clearly.

He made a simple assumption: dividing an adiabatic container into two equal compartments.

In the middle is a door controlled by a little fairy.

When air molecules undergo random thermal motion, they may collide.

We can selectively put faster molecules into one compartment and slower molecules into another.

This will make one of the compartments have a higher temperature than the other.

Therefore, the temperature difference can be used to drive a heat engine to do work.

Finally, they created a perpetual motion machine of the second kind.

Magnetic field radio frequency is a similar process.

How to accurately select high-energy atoms?

The faster an atom moves, the hotter it is; the slower an atom moves, the colder it is.

How can we ensure that we only kick away the hot ones and avoid touching the cold ones?

Lin Yu nodded; that was a professional question.

He turned around and picked up an energy level diagram from the blackboard.

This is all part of his knowledge base.

It's still within his capabilities to handle.

"That's a good question, Professor Chen. The key lies in the Zeeman effect."

"In a magnetic field, the energy levels of an atom will split, and the magnitude of the split depends on the magnetic quantum number and the amount of magnetic field."

"Cold atoms are trapped at the bottom of the magneto-optical trap, where the magnetic field is zero."

"The hot atoms oscillate near the well wall, where the magnetic field is stronger."

"so--"

Don't be fooled by the fact that Lin Yu is talking about some professional knowledge.

To put it simply, hot atoms and cold atoms cannot be together.

Lighter substances rise, while turbid substances descend.

Professor Chen's eyes lit up after hearing this.

The Zeeman effect was proposed to address the problem of quantization of magnetic moment and spatial orientation.

They haven't considered applying the Zeeman effect to this.

"So the degree of energy level splitting is different at different locations!?"

Lin Yu nodded in confirmation.

"That's right!"

"If the right radio frequency is selected, it is possible to control only the atoms in the strong magnetic field region."

"The atoms above are excited from the bound state to the unbound state, and they naturally escape."

"But the magnetic field of those cold atoms at the bottom of the trap is zero, the energy level does not split at all, the radio frequency field cannot resonate, so they are left behind."

After listening to Lin Yu's story, Old Chen was stunned for two seconds, then suddenly slapped his thigh.

"Brilliant! This design is brilliant!"

He nodded, indicating that he was fine.

Then he muttered something to himself and kept writing rapidly down his notes in his notebook.

Lin Yu looked at the field again, and there were still quite a few people raising their hands frantically.

So Lin Yu picked a middle-aged scholar in the second row.

"Comrade Lin, I am from the Department of Precision Instruments."

"You just said that BEC can be used in atomic clocks, I understand that."

"But I don't understand why you say it can be used in quantum computing."

"You just said that all the atoms in BEC are in the same quantum state."

"Isn't it just the exact same thing?"

"Quantum computing requires superposition states, entangled states, and so on—"

"If they're all the same, how can we calculate it?"

That's a very pointed question.

Fortunately, quantum computers and even quantum phones have emerged in later generations.

QuantumCTek has been working on this for 17 years, and quantum communication-enabled mobile phones are almost ready to be deployed.

"The teacher is right, BEC itself is indeed not a direct carrier of quantum computing."

At this point, Lin Yu paused deliberately and emphasized his words.

If someone could follow this direction and conduct research...

This could also make breakthroughs in the quantum field come sooner.

This is the real purpose behind Lin Yu's speech.

There are some kinds of knowledge that he doesn't need to hold onto all by himself.

The fastest way to develop a country is to hand it over to others and let them do it.

"We speculate that BEC is an excellent starting point for fabricating qubits."

"Why don't we all think about this carefully?"

A bit is the basic unit of data used by traditional computers to encode information in binary form.

The mobile data we use normally is in KB or MB. The B in that B stands for bit.

A qubit is something similar to a traditional bit in quantum computing.

"What is needed first to create qubits?"

The audience fell silent at first.

Then, a few students spoke up sporadically.

"We need to consider good coherence, long decoherence time, and precise control capabilities?"