Chapter 483 Quantum communication of more than 800 kilometers! Hear the fireworks again

It goes without saying that quantum hidden state transmission with five degrees of freedom is extremely difficult.

Because this first requires the observation of the five basic elements of photons.

Degrees of freedom refer to the basic properties of particles, such as spin, which is the spin direction of the particle. We can represent clockwise rotation as "1", and counterclockwise rotation as "0". 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 quantum teleportation with five degrees of freedom is realized, let alone the instantaneous communication between planets they are trying to achieve now, they will even be able to build a quantum network based on it.

Once the quantum network is completed, it will not only be beneficial to data security around the world, but also avoid 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 chance of anything being destroyed again.

Of course, this kind of thing needs to wait until later to discuss it. 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 originally come up with the idea of ​​using this method to observe spin and orbital angular momentum?"

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

The size of this device is not large, but just from the appearance, you can see its precision.

Pang Wei smiled and said, "You have already read the relevant information. I won't go into more technical details, 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, there is 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 achieve the observation of more degrees of freedom of particles, it means that we are more certain about the way this particle exists, just like we are peeling off its coat of uncertainty layer by layer. , and by the end, it became 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, although it is said so, wouldn't it be enough if we only understand a certain property of it? Spin, and orbital angular momentum, not It's just that it's spinning, but I need to determine which way it's spinning and the speed at which 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 had not forgotten a paper he had read. The team led by the author of that paper had achieved the observation of both waves and particles at the same time.

In this case, the so-called problem of only observing waves but not particles does not actually exist.

Thinking of this, his eyes lit up. If such an observation device could be made based on the method they originally experimented with, wouldn't it be possible to achieve observations with more degrees of freedom?

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

And since particle and wave properties can be observed at the same time, other methods can naturally be used to observe these five degrees of freedom.

Lin Xiao immediately walked aside, came to the computer, and found the paper that observed both waves and particles.

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

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

"Look at the methods used in this paper."

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

Lin Xiao said: "Change it."

"Magic transformation? How to do magic transformation?" Pang Wei was even more confused. What kind of transformation could be carried out in this experiment?

At this time, Lin Xiao opened another file. This file was the modeling diagram of Pang Wei's spin-orbit angular momentum super-entangled source measurement device.

Later, Lin Xiao began to modify the modeling diagram.

At this time, Pang Wei finally understood Lin Xiao's plan. He actually wanted to copy the experimental observation methods in this paper into their devices.

However, it is not enough to just observe wave and particle properties at the same time. After all, these two properties are just two broad categories and do not belong to intrinsic properties such as degrees of freedom.

And what kind of magical changes does Lin Xiao need to make so that they can observe its inherent nature?

Pang Wei was very curious about what kind of results the chief scientist could finally produce.

So just like that, half a month passed.

Lin Xiao took out his first result and began to assemble it.

The assembly took a month, especially when Lin Xiao dismantled their spin-orbit angular momentum observation device, which directly made Pang Wei and his research team's hearts twitch. .

In other words, the person in front of them was their chief scientist. Otherwise, when they saw Lin Xiao dismantling things, they would definitely kick him out immediately.

How can such an expensive and precise thing be dismantled?

But there is no way, who told it to be Lin Xiao?

So they also hoped that Lin Xiao could really produce results.

However, the first result still made them feel a little disappointed.

Because the first new observation device assembled by Lin Xiao failed.

"The wavelength as a degree of freedom was not observed, and even... the orbital angular momentum as a degree of freedom was also lost."

When a researcher reported this result, there was silence in the laboratory.

Although it has only been less than a month, it is normal even if it fails. The number of their failures was not calculated by time, but by book, because their failed experimental reports could be written into several books. .

But now it was Lin Xiao who failed.

Their invincible chief scientist of the country fell... ahem, failed?

Of course, Lin Xiao's eyes did not reveal disappointment. At the same time, he was not surprised by the result, but fell into deep thought again.

"Is it because the orbital angular momentum cannot be observed?"

"Is it because wavelength has wave properties, while orbital angular momentum has certain particle properties?"

"No, the problem definitely does not arise at this point. If you want to achieve simultaneous observation of waves and particles, even if a problem occurs, there should not be one spin left, or it should be that only one spin is observed. Particle nature, or only waves were observed.”

"So among these intrinsic properties, there should be some unclear correlations, wavelength...orbital angular momentum?"

At this time, Pang Wei came up, patted him on the shoulder and said, "It's okay, don't be discouraged yet, this is the first time."

Lin Xiao came back to his senses, and when he heard Pang Wei's words, he couldn't help but said: "Why do you think I am discouraged?"

Hearing Lin Xiao's words, Pang Wei was stunned for a moment, then smiled and said: "It seems that I am worrying too much. I wish I wasn't discouraged."

Lin Xiao shook his head, "There is not much to be discouraged. It's not like I haven't encountered problems before."

"Well, what have you gained now?"

"I can't talk about gains, I just have some ideas." Lin Xiao said, "I have to try again."

"Then try again. Scientific research is a process of trial and error anyway." Pang Wei nodded, and then said: "However, don't forget that the Chinese New Year is coming soon."

Lin Xiao was stunned, is the New Year coming soon?

Looking back at the time, it seems that this is indeed the case, 2027 is coming.

"Time flies so fast." Lin Xiao sighed with emotion. After the New Year, he would be 27 years old.

It's just that as his research on science deepens, it seems that there is nothing to commemorate such as age. For the time being, it can only be regarded as his body composed of 10^28 particles. After acquiring 'his' consciousness, the time that has passed is nothing more than, more strictly speaking, it must be expressed in cesium-133 atomic seconds.

Suddenly he was stunned, an atomic second?

time?

And quantum entanglement... intrinsic properties...

The atomic second is... in short, it is a very complicated way to determine the second, and it involves the period of the electromagnetic waves emitted or absorbed when the atoms transition.

Perhaps, starting from the calculation method of atomic seconds, he can find a way to observe the intrinsic properties of particles!

Thinking of this, he said: "No more words for now, I remembered something more important."

Then he left the place and continued what he had not finished yet.

Seeing Lin Xiao's hurried figure, Pang Wei smiled, then turned to look at the other researchers present who were still in a daze, and then said: "Okay, don't be in a daze, continue to do your own things. Maybe, our chief scientist will be able to bring us good news before the Chinese New Year."

…

Time flies like this, a few days before the New Year.

Just a few days before the Chinese New Year, Lin Xiao assembled the second observation device he developed.

"nailed it?"

After walking into the laboratory, Pang Wei looked at the things on the test bench and asked curiously.

Lin Xiao smiled slightly and said, "It's done."

"Three degrees of freedom?"

"Well, spin, orbital angular momentum, and wavelength."

Pang Wei nodded. Lin Xiao did not start with five degrees of freedom. After all, for this kind of technology, it is best to do it step by step.

Then he asked: "Then, let's try it now?"

"No, let's not try it now." Lin Xiao said.

Pang Wei was stunned for a moment, "If you don't try it now? When will you try it? It will be New Year's Eve in three days, and a lot of people in the research institute have gone back."

As he said this, he couldn't help but guess: "You're not going to leave the answer until after the year, are you?"

Lin Xiao just smiled faintly, and then said: "It's not the year after."

When Pang Wei became more and more confused about what Lin Xiao meant, Lin Xiao said: "Tonight, I will fly back to Qin Province, and then go to the quantum communication point in Xijing. You are here, I am there, let's have direct contact!"

Hearing Lin Xiao's plan, Pang Wei was stunned. "Are you...sure?"

The straight-line distance from Feishi to Xijing is more than 800 kilometers!

The longest quantum communication distance in the world now is only a hundred kilometers.

Is it going to be this intense from now on?

Lin Xiao smiled and said: "Of course I am sure. We must have the momentum to burn everything. If we don't succeed - I will go home directly to celebrate the New Year."

Pang Wei was stunned by his last words, and then said in a dumbfounded voice: "I'm just telling you, why are you still thinking about going to Xijing to do it?"

Lin Xiao spread his hands and said: "If I fail here, I might always feel something wrong in my heart, and then I won't go back during the New Year."

"So it's better to just play a big game. If you don't succeed, you can only choose to go home to celebrate the New Year."

Pang Wei smiled, and then asked: "But are you sure? This time it is more than 800 kilometers, and the probability of failure is still..."

Lin Xiao shook his head and said, "I believe in me and the three degrees of freedom."

Seeing that Lin Xiao had made a decision, Pang Wei finally said no more, nodded and said, "Okay, then I'll wait until tomorrow."

"Um."

Lin Xiao nodded and then stood up, "Then I'll leave it to you. I'm going to go back and pack my things."

"Okay." Pang Wei smiled and said, "See you next year."

"See you next year."

…

Lin Xiao took a flight back to Xijing that night.

After resting here for a night, he came to the quantum communication point in Xijing.

The quantum communication point in Xijing was only built in recent years. Since the distance of quantum communication was very limited before, cities were usually connected one by one and quantum communication points were established in these cities to achieve transmission.

But now, if Lin Xiao's communication over 800 kilometers away is successful, it will obviously not be so troublesome.

Therefore, Lin Xiao is now looking forward to their success.

When the Xijing Quantum Communication Point learned that Lin Xiao was coming here to conduct quantum communication experiments, they naturally welcomed him sincerely and provided Lin Xiao with the best help.

In this way, they quickly prepared the relevant equipment.

This equipment was naturally brought by Lin Xiao from Feishi. After all, if you want to connect the two devices, the first thing you have to do is to entangle the photons in the two devices. The entangled particles generally come from one Produced in events, only in this way can they be connected.

As for how to entangle two particles that are a certain distance apart, for now, they have no idea.

Therefore, the equipment brought by Lin Xiao can be entangled with the photons in the spin-orbit angular momentum-wavelength observation device he left at Pang Wei's side. Next, he only needs to control the shape of the photons on his side. It is possible to change the photons in the observation device through the entanglement effect, and the observation device can observe the spin, orbital angular momentum and wavelength of the photons inside, thereby determining the information.

"Chief Lin, everything is ready. When do you think the experiment will be carried out?"

A staff member said to Lin Xiao after completing all the debugging work according to Lin Xiao's preparation.

"good."

Lin Xiao nodded, then took out his cell phone and called Pang Wei.

The call was answered quickly.

"Old Pang, are you okay over there?"

"All of us are waiting for news from you."

Lin Xiao smiled and said, "Okay, I'll send you a message now!"

Then he walked to the computer nearby, thought about the control software, and entered a few words: May the world be peaceful.

Then, he pressed Enter.

Subsequently, these messages were converted into electrical signals by the computer and entered into the sending device next to him.

After the chip in the device receives the electrical signal, it then begins to control other components inside, causing the controlled photons inside it to react, and then responds according to the corresponding message.

Then, an invisible agitation broke through in an instant, as if breaking through a dimension, and arrived thousands of miles away in an instant, where the brand new three-degree-of-freedom entangled source was observed in the Feicheng Quantum Physics and Quantum Information Research Department. in the device.

…

"Every one of us wants world peace."

Pang Wei's voice rang from the phone.

A smile also appeared on Lin Xiao's face.

Of course, other people around him also burst into cheers.

Because they all saw that the message Lin Xiao sent was to hope for world peace.

And now, Pang Wei's answer on the phone undoubtedly means that he also knows what the message Lin Xiao sent.

This text message, which spanned 800 kilometers, surprised everyone just like the first sentence Alexander Bell said in the world's first phone call after he invented the telephone.

…

The news didn't stay hidden for long before it spread throughout the world.

Of course, it is only more than 800 kilometers, which does not surprise everyone. This news has attracted so much attention, largely because it was developed by Lin Xiao, and it is related to quantum communication. .

However, it is obvious that for those in the quantum communication community, this news is very valuable.

It once again broke through a degree of freedom, and also achieved information transmission over a distance of more than 800 kilometers. The breakthrough represented by this is very clear to these experts.

Immediately, scientists from various countries studying quantum communication were amazed by it.

"It's more than 800 kilometers. Are they preparing for the moon landing?"

"Why is this Lin always able to do such incredible things? Jesus Christ!"

"It's actually three degrees of freedom. This is incredible! How did he do it?"

"Physics, is there anything else that can stop him?"

…

However, just when the quantum communication community was extremely shocked and exclaimed that Lin Xiao was inhuman, Lin Xiaoze had already begun to live his new year.

Of course, his family members have also seen online reports about this technology, so they are also very curious about it.

So, while having New Year's Eve dinner, I started asking.

"Xiaoxiao, everyone on the Internet is saying that the new technology you have recently developed is very powerful, isn't it?"

"It's not a question of whether it's powerful or not, it's just that kind of rare..." Lin Xiao thought for a long time and found that she didn't know how to explain it to her parents so that they would understand, and finally said simply: "Anyway, it's quantum mechanics, it's very powerful."

"Technology and hard work?" Father Lin asked.

Hearing these words coming from his father's mouth, Lin Xiao was stunned for a moment, and finally couldn't help covering his face and said: "Dad! Stop shaking your hands!"

Hearing this kind of words from the elders always gave him a sense of world collapse.

But at this moment, the sound of fireworks suddenly sounded outside the window.

Yang Rong next to her took a look at the fireworks blooming outside the window and couldn't help but said: "Hey, there are still people who dare to set off fireworks now."

Father Lin smiled and said: "It seems that the higher authorities have approved the setting off of fireworks again. I don't know what happened, but it is a good thing."

"It feels a little like celebrating the New Year." Yang Rong also smiled.

At this time, Lin's father patted Lin Xiao's shoulder and said with a smile: "How about it? Let's go play for a while after eating. We haven't played in such a long time."

At this time, he noticed that Lin Xiao seemed to be stunned as he looked at the fireworks outside the window.

"Xiaoxiao?"

Lin Xiao came to his senses, then smiled and said: "Okay."

…

Fireworks can be set off during the Chinese New Year. This matter quickly became a hot topic and caused many people to discuss it. Although people don’t know why the ban on fireworks and firecrackers was introduced again, what is known is that the vast majority of people I felt very happy.

The young people called their friends to set off the long-lost firecrackers, and even the adults went to have fun and miss their childhood.

For Lin Xiao, he knew that the reason why he could fire off the cannon was because of his original proposal after the successful realization of controllable nuclear fusion.

But as the one who brought it all, he didn't have much time to enjoy this kind of entertainment.

After experiencing it with his father on New Year's Eve, he once again entered into his research the next day.

After all, three degrees of freedom are not enough. His goal is five degrees of freedom.

So, he spent the Spring Festival holiday in research again.

One month after returning to Fei Shi, he once again designed a four-degree-of-freedom entangled source observation device.

…