Chapter 482 Five-free quantum quantum hidden state transmission?
Although Lin Xiao felt that he had been cheated, there was no other way and now was not the time to refuse.
In other words, he generally would not refuse this kind of technology that he was actually interested in and had the purpose to study.
Of course, fortunately, after some understanding, he learned that Yueshisi and the Space Agency had invested a lot in research on these two technologies, and had achieved a lot of results.
For example, there has been a certain breakthrough in the dual-mode switching technology of aerospace engines.
The most important thing about an aerospace engine is that it can achieve seamless switching between an aerospace engine and an aerospace engine. Only in this way can an aircraft not only have the ability to fly in the atmosphere, but also have the ability to navigate in outer space. ability.
But the problem is that their current engine switching system is not perfect. The main problem is that the switching speed is relatively slow, especially the time required to switch from an aerospace engine to an aerospace engine. As for switching from an aerospace engine to an aerospace engine, it takes a long time. Engine timing is not that important.
Because when switching from aerospace engines to aviation engines, it must be when landing from the universe to the earth. At this time, relying on the aerodynamic design of the aerospace aircraft itself, it is completely possible to use the buoyancy of the air when landing. Glide, then complete the switch while gliding.
When switching from an aerospace engine to an aerospace engine, it is basically in a state of liftoff. At this time, the aerospace plane is about to break through the atmosphere into outer space. When the engine is switched, the aerospace plane is completely lost. gained motivation.
At this time, once the switching time is too long, the aerospace plane will slow down due to gravity, and may even stall completely, and finally the aerospace plane will begin to fall downwards.
At this time, they are likely to completely lose control of the aerospace aircraft, which will lead to an accident.
Therefore, in order to avoid this result, this system still needs to be improved to reduce the time required for switching.
As for another quantum communication technology, in fact, a long time ago, under the leadership of Academician Pang Wei, they have achieved long-distance communication from the surface of the earth to artificial satellites. However, obviously, this technology is not stable yet, and at the same time, it is not yet possible. Achieve communication over longer distances.
What Yue Shisi and the others know very well is that what they want to achieve is quantum communication between the earth and the moon.
However, Lin Xiao knows better than them that they want to realize quantum communication from the earth to Mars.
And obviously, the distance between these is a leap-forward improvement.
In 2022, they achieved 100 kilometers of direct quantum communication, which is the world's longest quantum information communication.
However, the shortest distance between the earth and the moon is 363,000 kilometers, not to mention the distance between earth and fire. The farthest distance between the earth and Mars is as high as 400 million kilometers, and even the closest distance is 55 million kilometers.
Apparently, the communication distance they are able to achieve now is not enough.
As for why quantum communication should be realized, it is for the delay-free nature of quantum communication.
Even a beam of light traveling from the earth to the moon has a delay of more than a second, not to mention the radio communication they use.
Their Yutu-2 lunar rover performs its mission on the back of the moon, and because the back of the moon always faces away from the earth, this means that the radio waves directly emitted by Yutu-2 cannot be received by the earth. .
Because it is obviously impossible for radio waves to pass through the moon and be received by the surface of the earth.
Therefore, the Queqiao lunar artificial satellite is needed to serve as a relay station. Therefore, several links have gone through in the middle. If the earth wants to receive it, it will take more than 12 seconds at the fastest.
Quantum communication is different. Unlike radio waves, its transmission requires electromagnetic waves as a carrier, so there is no need to worry about the moon blocking the signal. Using the non-delay nature of quantum entanglement, they can also communicate almost instantly. Get information and make connections between celestial bodies without delay.
And this will obviously be of great help to them when performing outer space operations.
Especially what they are facing now.
First of all, Lin Xiao knows very well that once they go to Mars, if any danger occurs, the instant communication advantage of quantum communication will allow them to respond immediately when the danger approaches.
After all, once you go to Mars, everyone is very clear about the dangers involved. Once quantum communication is established, this sense of crisis will be virtually eliminated, especially for those who will land on Mars in the future. For astronauts, it can be regarded as a kind of psychological comfort. After all, they can be in contact with their hometown all the time.
"Then the question now is, what technology should be studied first."
In Dingguang Research Institute, Lin Xiao thought about this issue.
And soon, he made a decision.
That is quantum communication technology.
Because compared to the aerospace aircraft, which has never been successful, quantum communication, which has already had successful cases, is relatively easier to study.
At least that's what he thinks now.
As for the aerospace plane, the problem to be solved is most likely a material problem. But now, he can feel a sense of helplessness when he hears the material problem.
Who knows that almost half of all the problems faced by this world are material problems.
So let’s solve this quantum communication problem first.
As for how to solve the quantum communication problem, Lin Xiao quickly thought of a good assistant, Pang Wei.
Although Pang Wei didn't seem to know about Yue Shisi, if he was studying quantum communication technology, it could obviously be studied regardless of whether he joined Yue Shisi or not.
Of course, Lin Xiao did not forget to ask Yue Shisi if he planned to let Pang Wei know about the moon monument. However, Yue Shisi rejected this proposal on the grounds that if it was unnecessary, try not to let too many people know. Moonstone Division.
Lin Xiao was not surprised to receive this reply, so he did not continue to ask more questions. He could only feel sorry for Pang Wei that he could not be exposed to this eye-opening news for all scientists.
Of course, maybe this news will be known to everyone in the future?
However, what will happen in the future is not something he needs to consider. Next, he only needs to find Pang Wei and invite him to study quantum communication technology together.
So then, he made a call to Pang Wei, and after Pang Wei learned that he wanted to study quantum communication technology, he naturally agreed without saying much. Who knew that he had this background?
Since the Quantum Physics and Quantum Information Research Department where Pang Wei works has relatively good quantum information research facilities and research environments, they decided to conduct research here, and Lin Xiao will go there in the near future.
After discussing various matters, Lin Xiao hung up the phone and then began to make preparations to go to Fei City.
…
A few days have passed, Quantum Physics and Quantum Information Research Department.
"Chief Lin, your Majesty's presence is too late to welcome you from afar."
When Pang Wei saw Lin Xiao getting out of the car, he smiled and greeted him.
Lin Xiao also said with a smile: "Academician Pang, Academician Pang, you asked me to help me research quantum computers before, now it's your turn to help me research it."
Pang Wei laughed loudly and said: "Of course there is no problem. My seven-foot body will be handed over to you, Chief Lin. I will do whatever you ask me to do. It just so happens that since Qiankun No. 1 was created After that, I basically had some free time and it was considered a holiday for myself.”
Lin Xiao was immediately speechless.
Good guy, you just take a vacation, and then you publicize my story by the way?
If it weren't for Pang Wei, Academician Tan Jinri of the Space Administration might not have found him so quickly.
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 it's no problem." Pang Wei nodded and said with a smile: "Of course, don't just borrow someone's head like Cao Cao did."
"Don't make it so scary." Lin Xiao waved his hand.
Pang Wei laughed a few times, then said no more, and took Lin Xiao into their quantum physics and quantum information research department.
Of course, Lin Xiao has been here many times. After all, Qiankun No. 1 is here, so he is quite familiar with the roads here.
In this way, they arrived at the quantum communication laboratory.
"This laboratory can connect with our quantum communication nodes across the country. Now it has basically covered 80% of the provincial capital cities in the country."
After entering the laboratory, Pang Wei briefly introduced the status of the laboratory to Lin Xiao.
"Awesome." Lin Xiao nodded and expressed appreciation.
These quantum nodes mainly communicate with the Micius quantum satellite in the sky, and then the 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, it is faster to send a message directly from Weixin than this method.
Because although quantum entanglement is completed instantaneously, the decoding process is not completed instantaneously, so the final speed is not as fast as the network speed on earth.
"Okay."
When he heard Lin Xiao's praise, Pang Wei just smiled slightly, 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 increase by leaps and bounds." ”
Then he asked curiously: "But having said that, Chief Lin, why did you suddenly decide to study this thing?"
Lin Xiao said with resentment: "This is all your credit, Academician Pang."
Then he told Pang Wei the reason.
Pang Wei was stunned, "Academician Tan Jinri of the Space Administration listened to me..."
Halfway through, he burst into laughter and said, "How great is this, Chief Lin, you are famous now."
Lin Xiao rolled his eyes, "Now that we have quantum communication technology, I don't even dare to think about what else I will be asked to do in the future. Maybe one day they want to transform Mars, will they have to find me?"
"He who can do it should work harder." Pang Wei smiled and patted Lin Xiao on the shoulder, and then walked to the laboratory with Lin Xiao.
There are other people in the laboratory, and these people are Pang Wei's quantum communication research team.
After 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: "Chief Lin, are you going to lead us to study quantum communication between the earth and the moon?"
Lin Xiao smiled slightly and said, "Why is it just the earth and moon, but not the earth and fire?"
"Ah this..."
These people were immediately stunned. Do they actually want to study quantum communication between Earth and Mars?
This level of difficulty is simply an improvement in quantitative level.
After all, one is three to four hundred thousand kilometers away, while the other one is at least 55 million kilometers away. Usually it is 100 million kilometers away. This kind of difficulty cannot be said to be small.
But then Lin Xiao said with a smile: "Of course, I'm just telling you that we need to set our goals in the longer term, and for now, let's just realize quantum communication between the earth and the moon. "
Hearing this, the researchers breathed a sigh of relief, then nodded and responded: "Yes! Chief Lin!"
At this time, Pang Wei also came out and said with a smile: "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 Chief Lin's help, we can really do it." Did it happen?"
After hearing Pang Wei's words, these researchers thought, it seems that this is also the case?
As a result, they all looked at Lin Xiao more eagerly.
Hey, if they could really achieve ultra-long-distance quantum communication between earth and fire, they would be awesome.
Lin Xiao shook his head in a funny way and stopped talking nonsense. Then he said: "Okay, let's not talk about these things for now. Let me talk about the key points of our topic first."
Hearing Lin Xiao's key point, these researchers all became serious and looked at Lin Xiao. Pang Wei also came to the side and looked at Lin Xiao.
"The quantum communication distance we have achieved now is very limited. I believe everyone knows the reason."
“During the process of quantum teleportation, the quantum state that we carry quantum information will suffer from quantum decoherence, eventually causing our transmission to fail.”
"This quantum decoherence effect is relatively strong on the surface of our earth, because the 'observation' effect is relatively strong on the surface of the earth, so this makes it very difficult for us to achieve quantum communication on the surface of the earth. Difficulty, we 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 humans can observe it, it becomes certain. .
It’s just that ‘observers’ are not limited to people. Anything that can cause the measurement of ‘quantum’ will cause this quantum entanglement to disappear.
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, which means that only the receiver's observation ' to get the correct information.
Once a third party wants to intervene in this process, the third party's 'observation' will cause its quantum state to collapse, and because of its illegality, the real message cannot be obtained, and the original sender and receiver It will also be noticed that a third party is trying to observe because of the changes in the quantum state. To put it simply, quantum communication also has an anti-eavesdropping function.
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 longer-distance quantum communication."
Lin Xiao said.
"How to do it?" Pang Wei asked at this time: "Is it possible that you want to add more degrees of freedom in teleportation?"
"Yes, only this method can make our quantum teleportation more stable and suffer less decoherence effects."
Lin Xiao nodded and said with a smile.
"But you should also know that the more freedom you add, the more difficult it is to implement."
"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 brightest spin-orbit angular momentum super-entangled source measurement device."
Pang Wei smiled when he heard Lin Xiao mention this. The project he completed back then can be regarded as one of the most commendable among his many achievements.
Because after realizing single-free quantum teleportation for the first time in 1997, his achievement also realized multi-freedom quantum teleportation, which means that by observing the spin direction and orbital angular momentum of photons, All can receive information, which improves the stability of quantum communication and extends the distance.
This achievement was also rated as the top ten major breakthroughs in the field of physics that year.
But at this moment, Lin Xiao squinted 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 before we can truly realize interstellar quantum communication."
"Do you want to realize three degrees of freedom?" Pang Wei looked at Lin Xiao's eyes and said in disbelief.
Any increase in the degree of freedom represents an exponential increase in difficulty.
It was 18 years after he completed quantum teleportation with one degree of freedom in 1997 that he completed quantum teleportation with two degrees of freedom, and the more degrees of freedom, the more difficult it is to complete.
If it were three degrees of freedom, God knows how difficult it would 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, if Lin Xiao's idea spreads, the quantum information world will probably boil.
Because there is no doubt that, for the current quantum information community, wanting to realize quantum hidden state transmission with five degrees of freedom is equivalent to the "forever fifty years" that was said before controllable nuclear fusion was realized.
It's basically the same as saying it's impossible.
Everyone present swallowed their saliva, and suddenly felt a sense of Alexander. The difficulty of realizing quantum communication between earth and fire that Lin Xiao just mentioned seems to be somewhat similar to this, right?
If five degrees of freedom are really realized, it seems that they can really realize quantum communication between earth and fire?
When Lin Xiao saw these researchers looking like they were facing a formidable enemy, he finally smiled and said, "Don't worry so much, let's just take it slow."
"And Lao Pang, you just said that you let me do whatever I want."
Pang Wei shook his head helplessly and said: "Okay, okay, hey, you let me board your pirate ship."
Lin Xiao laughed, otherwise, how could I let you experience how I felt back then?
It's a pity. The original initiator, Academician Li Gang of the Institute of Plasma, seems to have retired. Otherwise, he would really want to find a project to involve Li Gang.
He sighed in his heart, and then he said: "Well, no more nonsense, let's start with the first item, how to control these degrees of freedom stably."
Then, he walked to the small blackboard nearby, found a pen, and started writing on it.
"First of all, we have to start with quantum decoherence and discuss 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 couldn't help but light up after thinking carefully.
seem……
Lin Xiao was actually prepared for it?
It’s not like I just started doing it without thinking about it.
Thinking of this, he also smiled slightly, this is the chief scientist who can convince all of them.
Then he motioned to the others and asked them to learn from Lin Xiao. He also took out a pen and paper and began to think along Lin Xiao's steps.
And this topic about how to realize quantum communication between planets has officially begun.
…
