From Almighty Scholar to Chief Scientist

If it weren't for Pang Wei, academician Tan Jinri of the space agency might not have found him so soon.

In the end, he could only pat Pang Wei on the shoulder and said: "Okay, Academician Pang, this is what you said, I remember, your seven-foot body-oh, strictly speaking, it should be your mind, I want to put it to good use."

"Of course no problem." Pang Wei nodded and said with a smile, "Of course, don't borrow someone's head like Cao Cao."

"Don't say it so scary." Lin Xiao waved his hand.

Pang Wei laughed a few times, and without further words, he led Lin Xiao into their quantum physics and quantum information research department.

Of course, Lin Xiao has been here many times. After all, Qiankun No. [-] is here, so he is familiar with the road here.

In this way, they arrived at the Quantum Communication Laboratory with three turns and two turns.

"This laboratory can communicate with our quantum communication nodes all over the country, and now it has basically covered [-]% of the provincial capital cities in the country."

After entering the laboratory, Pang Wei briefly introduced the status of the laboratory to Lin Xiao.

"Excellent." Lin Xiao nodded and praised.

These quantum nodes mainly communicate with the Micius quantum satellite in the sky, and then Micius transmits information to other quantum nodes.

Of course, the main use here is the confidentiality of information in quantum communication, not the delay, because in terms of delay, sending a message directly from Weixin is faster than this method.

Because although quantum entanglement is completed instantaneously, the decoding process is not instantaneous, so the final speed is not as fast as the network speed on the earth.

"Okay."

Hearing Lin Xiao's praise, Pang Wei just smiled, and then said: "Quantum communication at this distance is nothing. If you want to realize quantum communication between the moon and the earth, the difficulty will be a leap forward." gone."

Then he asked curiously: "But having said that, Chief Lin, why did you suddenly decide to study this thing?"

Lin Xiao said resentfully, "This is all thanks to you, Academician Pang."

Then he told Pang Wei the reason.

Pang Wei was taken aback, "Academician Tan Jinri of the Space Administration listened to me..."

Halfway through the speech, he burst out laughing, "How wonderful this is, Chief Lin, you are well-known now."

Lin Xiao rolled his eyes, "Now it's quantum communication technology, and I don't dare to think about what I will do in the future. Maybe one day they want to transform Mars, so they have to find me too?"

"It's more work for those who can." Pang Wei smiled and patted Lin Xiao's shoulder, and then walked into the laboratory with Lin Xiao.

There are also other people in the laboratory, and these people are Pang Wei's quantum communication research team.

When these people saw Lin Xiao, their faces showed excitement and admiration, and they all shouted: "Hello, Chief Lin!"

"Hello." Lin Xiao smiled and nodded towards them.

At this time, one of them asked again: "Chief Lin, are you going to take us to study the quantum communication between the earth and the moon?"

Lin Xiao smiled slightly and said, "Why can't it be Earth Fire if it's just Earth Moon?"

"Ah this..."

These people were stunned for a moment. Do they still want to study the quantum communication between the earth and Mars?

This difficulty is completely an increase in the quantitative level.

After all, one is 40 million kilometers, and the other is at least 5500 million kilometers. Usually, it is 1 million kilometers away. This kind of difficulty is not insignificant.

But then Lin Xiao smiled and said: "Of course, I'm just telling you that we need to set our goals in the longer term, but for now, let's just realize the quantum communication between the earth and the moon. "

Hearing this, the researchers breathed a sigh of relief, then nodded, and replied, "Yes! Chief Lin!"

At this time, Pang Wei also came out with a smile and said: "Okay, you guys, think about Chief Lin's past achievements, even if we really want to engage in Earth Fire Quantum Communication, if we have the help of Chief Lin, we will really Did it come out?"

Hearing Pang Wei's words, these researchers thought, it seems to be the same reason?

Ever since, their eyes on Lin Xiao became more eager.

Hey, if they can really realize the ultra-long-distance quantum communication between the earth and fire, then they will be amazing.

Lin Xiao shook his head amusedly, and stopped talking nonsense, and then said: "Okay, let's not talk about these things, let me talk about the key points of our project first."

Hearing that Lin Xiao was going to make a point, these researchers all became serious and looked at Lin Xiao, and Pang Wei also came to the side and looked at Lin Xiao.

"Now the quantum communication distance we realize is very limited. I believe everyone knows the reason."

"In the process of quantum teleportation, the quantum state that we carry quantum information will be subject to quantum decoherence, which will eventually cause our transmission to fail."

"And this quantum decoherence effect is relatively strong on the surface of our earth, because on the surface of the earth, the effect of 'observation' is relatively strong, so this also makes it very difficult for us to realize quantum communication on the surface of the earth. Difficult, need the help of satellites."

As we all know, "quantum" is uncertain, and once it is observed, it will collapse, just like our time, the future is uncertain, but when the future becomes the present and human beings can observe it, it becomes certain up.

It's just that the "observer" is not limited to human beings. Anything that can cause the measurement of "quantum" will lead to the disappearance of this quantum entanglement.

This can also be used to understand the confidentiality of quantum communication, because in the process of quantum communication, when the sender sends a message, the only legal observer is the receiver, that is to say, only the receiver can observe ', in order to get the correct information.

And once a third party wants to intervene in this process, the "observation" of the third party will cause its quantum state to collapse, and because of its illegality, it will not be able to get the real news, while the original sender and receiver Because of the change of the quantum state, it is also noticed that a third party is trying to observe. In simple terms, it means that quantum communication also has the function of anti-eavesdropping.

All in all, other observations will cause the information transmitted by quantum entanglement to not be transmitted normally, or even destroy this quantum entanglement state.

"So, what we have to do is to make a quantum entanglement controller and observation device that can reduce external interference."

"In this way, we can achieve more long-distance quantum communication."

Lin Xiao said.

"How to do it?" Pang Wei asked at this time: "Do you want to add teleportation with more degrees of freedom?"

"Yes, and only this method can make our quantum teleportation more stable and suffer from lower decoherence effects."

Lin Xiao nodded and said with a smile.

"But you should also know that the more degrees of freedom you increase, the more difficult it is to achieve."

"Of course I know." Lin Xiao nodded and said, "I also remember that in 2015, the team led by you, Academician Pang, realized the world's highest brightness spin-orbit angular momentum super-entanglement source measurement device."

Hearing Lin Xiao mention this, Pang Wei smiled. The project he completed at the beginning can be regarded as one of the most commendable of his many achievements.

Because after realizing the single-freedom quantum teleportation for the first time in 1997, his achievement realized the multi-freedom quantum teleportation, that is to say, by observing the spin direction and orbital angular momentum of the photon, All can receive information, which improves the stability of quantum communication and extends the distance.

And this achievement was also evaluated as the top ten major breakthroughs in the field of physics that year.

But at this moment, Lin Xiao narrowed his eyes and said, "But just two degrees of freedom are not enough. There are many degrees of freedom. We need to continue to make breakthroughs to truly realize interstellar quantum communication."

"Do you want to realize three degrees of freedom?" Pang Wei looked at Lin Xiao's eyes and said incredulously.

The improvement of any degree of freedom represents an exponential expansion of the difficulty.

In 1997, he completed quantum teleportation with one degree of freedom 18 years later, and he completed quantum teleportation with two degrees of freedom, and the more degrees of freedom, the more difficult it is to complete.

If it is three degrees of freedom, God knows how difficult it will be.

However, at this time, Lin Xiao's calm voice remembered: "No, I want to achieve five degrees of freedom."

"Spin, orbital angular momentum, polarization, wavelength, and momentum."

Now, not to mention the people present, but if Lin Xiao's idea is spread, the quantum information world will probably be boiling.

Because there is no doubt that to achieve quantum teleportation with five degrees of freedom, for the current quantum information community, it is simply equivalent to the "forever 50 years" that was spread by word of mouth when controllable nuclear fusion has not yet been realized.

Basically tantamount to saying it's impossible.

All the people present swallowed their saliva, and suddenly felt a kind of Alexander. The difficulty of realizing the quantum communication between the earth and the fire that Lin Xiao said just now seems to be similar to this difficulty?

If this really achieves five degrees of freedom, it seems that they can really realize the quantum communication between the earth and fire?

And Lin Xiao saw the appearance of these researchers as if they were facing a formidable enemy, finally smiled and said, "Don't be so worried, everyone, let's take it slowly."

"And old Pang, you said just now, let me do whatever I want."

Pang Wei shook his head helplessly, and said, "Yes, yes, hey, you can count me on your boat."

Lin Xiao laughed, otherwise, how could I let you experience my original feelings?

It's just a pity that the original instigator, academician Li Gang of the Institute of Plasma, seems to have retired, otherwise, he really wants to find a project sometime to bring Li Gang into it.

He sighed in his heart, and then he said: "Then, let's not talk nonsense, let's start with the first item, how to control these degrees of freedom stably."

Then, he walked to the small blackboard beside him, found a pen, and began to write on it.

"First of all, let's start with the discussion of quantum decoherence, how to deal with the quantum decoherence effect..."

【Ex(t)|Ey(t)∝e...】

As Lin Xiao wrote more and more formulas on the blackboard, Pang Wei's eyes lit up after serious thinking.

seem……

In fact, Lin Xiao was already prepared?

It didn't just start off without a second thought.

Thinking of this, he also smiled slightly, this is the chief scientist who convinced them all.

Then he motioned to the others to let them learn from Lin Xiao, and he also took out a pen and paper, and began to follow Lin Xiao's steps to think.

And this topic about how to realize the quantum communication between planets officially started.

……

Chapter 485 Quantum communication over 800 kilometers!I heard the sound of fireworks again

It goes without saying that quantum teleportation with five degrees of freedom is extremely difficult.

Because it is first necessary to observe the five basic elements of photons.

The degree of freedom refers to the basic properties of the particle, such as spin, which is the spin direction of the particle. We can represent "1" by clockwise rotation, and "0" by counterclockwise rotation. In addition, there are orbital angular momentum, Wavelength, etc., these things can represent a kind of information, and finally after translation and conversion, the information can be identified accordingly.

However, in order to achieve this kind of observation, there are also great requirements for the observation devices they need to manufacture.

All in all, once the five-degree-of-freedom quantum teleportation is realized, not to mention the instant communication between planets that they want to achieve now, they can even build a quantum network based on it.

Once the quantum network is built, it will not only benefit the data security of the world, but also avoid things like optical cables that need to rely on wires to transmit data. In this way, there is no need to worry about submarine optical cables in Europe. There is no possibility of being destroyed again.

Of course, this kind of thing needs to be discussed later. For now, what they need to do is to successfully realize the connection between the planets.

In this way, as time passed, Lin Xiao's research gradually entered the deep water area.

……

"How did you come up with the idea of ​​using this method to realize the observation of spin and orbital angular momentum?"

In the laboratory, Lin Xiao visited the spin-orbit angular momentum super-entanglement source and measurement device developed by Pang Wei.

The size of this device is not large, but the precision can be seen just from the appearance.

Pang Wei smiled, "You've already read the relevant information, so I won't say much about the technical aspects, but let me tell you what I thought at the beginning... Well, this is indeed a problem."

"If you want to observe two degrees of freedom at the same time, the first difficulty lies in the uncertainty principle. It is impossible for us to observe the position and momentum of a particle at the same time. After all, wave-particle duality, so before that, people generally It is believed that we can only observe one degree of freedom at most, and it is difficult to observe more degrees of freedom."

"Because this means that once we realize the observation of more degrees of freedom of a particle, it means that we are more certain about the existence of this particle, just like we peel off its uncertain coat layer by layer. , and in the end, it becomes certain.”

"So, in a way, the more degrees of freedom we determine, it's like challenging the 'truth' of uncertainty."

"Challenge the truth?" Lin Xiao couldn't help but smile, "Maybe."

Pang Wei nodded, and then said: "But at that time, I thought in my heart that although I said so, if I only find out one of its properties, wouldn't it be enough? Spin, and orbital angular momentum, are not It's all spinning, it's just that I need to determine which way it's spinning and how fast it's spinning."

Lin Xiao nodded slightly, but he was thinking in his heart, could it really only be observed in one direction?

This is not necessarily the case.

After all, he has not forgotten a paper he read at the beginning. The team led by the author of that paper realized the observation of waves and particles at the same time.

In this way, the so-called problem that only waves can be observed but not particles does not exist.

Thinking of this, his eyes light up. If such an observation device can be made according to the method they experimented with at the beginning, wouldn't it be possible to achieve more freedom of observation?

Particle nature and wave nature are two major categories, while spin, orbital angular momentum, wavelength, polarization, and momentum can respectively reflect these two categories.

Since particle and wave properties can be observed at the same time, it is natural to use other methods to observe these five degrees of freedom.

Lin Xiao immediately walked aside, came to the computer, and found the paper in which waves and particles were observed at the same time.

When Pang Wei saw his movements, he stepped forward and asked in doubt: "What's wrong? Do you have any ideas?"

However, Lin Xiao did not speak for the time being, but relied on his own impression to find the paper, and then showed it to Pang Wei.

"Look at the method used in this paper."

After taking a look, Pang Wei made an evaluation: "I have read this paper too. It is a very interesting and good experiment, but what are your plans?"

Lin Xiao said, "Change it."