The battle that broke out in space, the people on the moon did not know, Qin Yi's surveillance satellite had been watching the situation of the Earth and the new life, so Minsk had already gotten the news, but most people did not know what was happening.

After leaving from the underground ruins of this lost civilization, Sun Tan took Mark and them to a nearby abandoned factory, which was originally one of the food factories in No. 3 New Town, but later abandoned due to project changes and other reasons, although there is no one left, but there are still a lot of supplies and fuel in the warehouse, which can be replenished.

The group recovered for a while, Sun Tan took out all the information recorded before and sorted it out, as soon as he studied something, he would enter a state of high concentration, sometimes Mark called him, he would be immersed in his own world and couldn't hear it at all.

"I've found something good!" After Sun Tan had been tinkering with the instrument for several hours, he suddenly let out a scream.

"Damn, scare Lao Tzu, what are you excited about......" Mark rubbed his ears, and Sun Tan's cry suddenly came from the communicator, which made his ears numb.

"Come and see this."

Sun Tan connected a USB flash drive-like thing to the old-fashioned screen on the wall, Sun Tan simply handled it and it could be used normally, two dark green arcs appeared on the pale green background of the screen, they were constantly winding, staggering at a certain frequency, like two entangled snakes, one large and one small.

"What is this?" Mark couldn't see why.

"The AI of the lost civilization has used dozens of methods to send warning signals to us, only the electromagnetic wave signal is what we can use now, and the mysterious cube is really shielded by the electromagnetic wave signal, which proves that the most basic and low-level communication method of most civilizations is electromagnetic waves, in addition, gravitational waves and pulse waves are within our understanding, but we do not have a large device that transmits this signal for the time being, and this, I think is the only thing we can imitate." Sun Tan pressed a button, and the winding order of the strange snakes on the screen began to speed up, they were staggered and entangled, and finally seemed to become a fusiform, Mark was a little dazzled, and Sun Tan said faintly: "This is ultra-distance quantum transmission, I think this is the only possibility for us, if we break through this technology, we can easily stop the mysterious cube." ”

"I don't understand it, but it's amazing." Mark touched his chin and said.

"You are as stupid as you are, and you are good friends with Sun Tan like this?" Nina suddenly hung upside down from one of the beams above, startling Mark, and she smirked and said, "It couldn't be easier, you listen to me." To put it simply, it is the over-distance effect on the basis of traditional quantum communication, the most basic quantum communication technology was discovered as early as 1993, and the BB84 protocol formulated at that time also laid the foundation for later quantum communication, and the over-distance transmission is realized by the principle of quantum entanglement, for example, A wants to transmit target X to B, and they each have a photon pair A and B in their hands, and A binds them to each other by winding photons, which forms a classical channel, and then A does Bell joint measurement of A in his hand, because it is observed, The quantum state of target X then collapses, A changes, and at the same time, B and A as the entanglement state also change, and all the information carried by X will be transmitted to B, which is called over-distance transmission. ”

"Hmm......" Mark had a blank expression.

"Do you understand?" Nina asked with a wink.

"I don't understand at all! What the hell are you talking about? Mark broke down and said, "If I had been so smart, I wouldn't have been reduced to working on the moon!" ”

"Well, I know, you probably understand anyway, but how are you going to build a bridge around photons?" Nina turned to Sun Tan again.

"The meal has to be eaten in one bite, things have to be done step by step, it is not yet that step, the first thing to do is to need a large quantum computer, enough computing power to reverse the content of quantum entanglement communication, my record is very rough, after all, there is only such a little thing in hand, the urgent need is to crack the way the AI of the lost civilization sends information, we have recorded a complete quantum ultra-distance communication for the first time, this is the first step, but the ancient people saw the plane, and it took time to deduce how the plane flew."

"All I know is the lake." Mark said that Huguang is the most advanced quantum computer on the moon, and it is still being experimented, and the space launch station in the new city of No. 8 on the far side of the moon is now used by Qin Yi to monitor the white cube.

"That's too dangerous, and Minsk is not stupid." Sun Tan immediately rejected Mark's proposal, "Now it's not about being useful, it's about being usable." ”

"I know a place!" Nina suddenly had an idea: "Geological Center! ”

"Is there there?"

"Yes, it is used to monitor the trajectory of meteorites, because the moon is often attacked by meteorites, so a very large meteorite defense system is arranged, and ordinary computers cannot carry this level of defense mechanism." Nina said as she took out Sun Tan's tablet from the mecha, called up the previous map and pointed to a location on it.

"Isn't that just right in City Three? It's so close to us! Mark laughed, thinking that there was no end to it.

"How's the guard over there?" Sun Tan asked Nina.

"Now in an emergency, the inside should have been evacuated, this kind of place will definitely be closely protected, but compared to the lake...... This kind of security is lax. Nina said.

"That's just going to bite the bullet and find a way to create a hole in the defenses, and we'll take the opportunity to sneak in."

"How long will it take you?"

"It's hard to say, it could be a few hours, it could be a whole day, I don't know how efficient that computer is." Sun Tan worried.

"That's not easy, it's easy to distract the guards for a few hours, but it's impossible to keep them from coming back all day, right?" Nina had a grim expression on her face.

"Then we have to go and see how it goes, it's better than staying here." Sun Tan slapped his thigh and decided, stretched out his fist and stood up, "Let's go!" ”

Nina and Mark also reached out their fists and bumped into him, and the three of them quickly packed up their materials and erased the traces of their own visits before they finally set off for Moon New City 3.