Chapter 256, Quantum Communication

"The surrounding gravity is normal. It is definitely not a black hole. It must be the entrance and exit of the space-time ocean current."

Chen Bin began to study it carefully as if he had discovered something new. If it was a black hole, the gravity around it would be abnormal due to the huge mass of the black hole. It can be easily found through the gravitational telescope, but there is no abnormality now, which means it is not gravity.

"Launch a small spaceship into it."

The hatch of the huge elliptical flying saucer-shaped spaceship slowly opened, and a small unmanned spaceship slowly flew out. It was powered by plasma. It dragged a long, bright white tail flame towards the entrance and exit of the space-time ocean current. It was like a firefly in the dark void, very clear.

When this unmanned spaceship entered the range of the entrance and exit of the space-time ocean current, it disappeared almost instantly, as if it was swallowed up by the surrounding darkness.

"Lost contact, no radio contact."

"Well, it seems to have entered the space-time ocean current. The speed of flight in the space-time ocean current exceeds the speed of light, and it should be able to shield electromagnetic waves. Only after it leaves the space-time ocean current and arrives at the Centaurus Galaxy can it contact us again. However, the Centaurus Galaxy is 4.3 light years away from us, and it will take several years at the speed of electromagnetic waves."

Chen Bin nodded. He was now very sure that this was the entrance and exit of the space-time ocean current. Through this space-time ocean current, he could reach another galaxy in a very short time.

"Haha, brothers, I have discovered the space-time ocean current here."

In the virtual chat world, Chen Bin happily shared the good news, but other people could not receive it for a while. Compared with the vast universe, the solar system seems insignificant, but it is still very vast. Even at the speed of electromagnetic waves, it takes several hours to contact the earth from here. The time for this round trip has to be multiplied by 2.

It can be said that in the vast universe, not only transportation technology restricts human beings from moving towards the universe, but also communication technology. Even if the speed of electromagnetic waves reaches the speed of light, it is still too slow in the universe of light.

A few hours later, Li Fu finally received Chen Bin's message from the earth, which is dozens of astronomical units away.

"Yu Liang, Tang Boyuan, Dong Zhifei, Luo Xiaoyao, Zhan Fei, Chen Bin has discovered the space-time ocean current here. Do you have any gains?"

Li Fu began to contact people in other directions. Basically, a spacecraft was sent to explore the star system closest to the solar system in each direction.

"We have also discovered the space-time ocean current in the direction of the Canis Minor galaxy, which is 11 light years away from the solar system."

Yu Liang replied at this time.

"The space-time ocean current in the direction of Aquila has also been discovered, and is currently being accurately positioned."

Tang Boyuan also has some gains. The Aquila galaxy is 16 light years away from the solar system.

"No space-time ocean current has been found in the direction of the Piscis Austrinus galaxy for the time being, and it is still being detected."

Luo Xiaoyao has no gains. The Piscis Austrinus galaxy is 22 light years away from the solar system.

"No space-time ocean current has been found in the Piscis Austrinus galaxy, which is 22 light years away from the solar system. If so, there will be no space-time ocean current connection when the distance is more than 20 light years?"

Li Fu summarized everyone's data and analyzed them carefully.

"Luo Xiaoyao, Zhan Fei, Dong Zhifei, you guys keep searching for a few more days. If you don't find anything, it means that the distance may exceed and there is really no space-time ocean current to return to Earth."

It was just a few messages, and it took several days to go back and forth. Because the distance is too far, a distance of dozens of astronomical units, it takes more than ten hours for the electromagnetic signal to go back and forth. This is really hard to accept for people who are now accustomed to real-time communication.

"It seems necessary to develop quantum communication technology. Communication within the solar system has been delayed to this extent. If we still rely on current communication technology to communicate with other galaxies in the future, let alone whether we can communicate, the time alone will be calculated in years."

"Even the nearest Centaurus galaxy is 4.3 light years away from the solar system. It takes 8.6 years for the electromagnetic wave to go back and forth. In such a long time, the daylily has bloomed and fallen many times."

Li Fu began to think in his mind. Communication technology and transportation technology are the two things that really restrict human pace. Just like in ancient times, it is impossible to rule the entire earth by riding horses and pigeons. The collapse of the vast Mongol Empire was actually because the territory was too vast. The central government was simply powerless to deal with remote areas. Under certain conditions, such a vast territory would only be short-lived.

Only in modern times, with the rapid development of transportation and communication technologies, it is no problem to bring the entire earth under the rule of one country, not to mention the territory as large as the Mongol Empire, because powerful transportation and advanced communication technologies are enough for rulers to mobilize forces from all over the world to support any corner in a very short time.

However, in the interstellar era, the universe is even more vast and boundless, and even the speed of light is very slow. Just within the solar system, electromagnetic wave communication seems to have failed to keep up with the requirements of the times.

The quantum communication technology mentioned by Li Fu is the next generation of advanced communication technology proposed by scientists. The principle of quantum communication technology is a technology proposed based on the principle of quantum entanglement effect.

Quantum communication is mainly based on the theory of quantum entanglement state, and uses quantum teleportation (transmission) to realize information transmission. According to experimental verification, no matter how far apart two entangled particles are, as long as one changes, the other will change instantly.

The process of using this feature to realize quantum communication is as follows: construct a pair of entangled particles in advance, place the two particles on both sides of the communication, and jointly measure the particles with unknown quantum states with the particles of the sender (an operation). Then the particles of the receiver collapse (change) instantly, and collapse (change) into a certain state. This state is symmetrical with the state of the particles of the sender after collapse (change). Then the information of the joint measurement is transmitted to the receiver through the classical channel. The receiver performs a unitary transformation (equivalent to a reverse transformation) on the collapsed particles according to the received information, and obtains the unknown quantum state that is exactly the same as the sender.

To put it simply and easily, quantum is like a pair of twin brothers, and the twin brothers are copies of each other. If one raises his right hand, the other will also raise his right hand. If one laughs, the other will also laugh. No matter what action any one of them makes, the other will also make the same action.

And no matter how far apart the two brothers are, the actions between the two brothers in any state are always the same, and there is no time difference between them, and there will be no difference because of the distance. This is the entangled state of quantum.

Because of this characteristic of quantum entanglement, the power of quantum communication technology came into being. In theory, quantum communication technology can ignore distance. No matter how far the distance is, quantum communication technology can achieve real-time communication without any delay.

Regardless of the distance of communication technology, this is definitely a technology that must be mastered for space travel and interstellar colonization. No matter how far the distance is, you can keep in touch anytime and anywhere, and there will be no communication delay because the distance is too far.

In addition to the specificity of contacting at any time regardless of distance, quantum communication technology has several other characteristics that scientists are full of praise for, one of which is security.

Compared with traditional communication technology, quantum communication cannot be compared with it in terms of security and efficiency. In terms of security, quantum communication will never "leak" information. One of them is that the key of quantum encryption is random. Even if it is intercepted by the thief, the correct key cannot be obtained, so the information cannot be cracked.

Second, if the quantum state of one of the two particles in the hands of the two communicating parties changes, the quantum state of the other party will change immediately. According to quantum theory, any macroscopic observation and interference will immediately change the quantum state and cause it to collapse. Therefore, the information obtained by the thief due to interference has been destroyed and is not the original information.

Another thing is that quantum communication is very efficient. The unknown quantum state being transmitted will be in an entangled state before being measured, that is, it represents multiple states at the same time. For example, a quantum state can represent two numbers 0 and 1 at the same time. 7 such quantum states can represent 128 states or 128 numbers at the same time, that is, 0~127. One transmission of optical quantum communication is equivalent to 128 transmissions of traditional communication. It is conceivable that if the transmission bandwidth is 64 bits or higher, the efficiency difference will be amazing.

Of course, many people may not understand quantum entanglement. Quantum entanglement can be understood by "Schrödinger's cat": when a cat is placed in a box with poison, and then the box is covered, after a while, ask the cat whether it is dead or alive?

The answer of quantum physics is: it is both dead and alive. Some people will say that you can know it by opening the box. Yes, you can know whether the cat is dead or alive by opening the box, but according to the explanation of quantum physics: this state of death or life is the result of human observation, that is, the macroscopic interference of humans makes the cat dead or alive, not the real state when the box is covered. Similarly, microscopic particles have been in a superposition of "death" and "alive" before being "interfered". It can also be said that it is both "0" and "1", so the security guarantee of quantum communication technology is very reliable.

Because of the characteristics of quantum entanglement, even if you intercept the information, because of the characteristics of entanglement, when you try to crack the information macroscopically, the quantum state will be changed immediately, causing it to collapse. Therefore, the information obtained by the thief due to interference has been destroyed and is not the original information.

Quantum communication technology has three characteristics: real-time, security, and efficiency, none of which is possessed by traditional communication technology.

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