Chapter 242: Something New Every Time In the living room, after cleaning up Xu Qingzhou, Song Yao got up from the sofa angrily, her cheeks redder than before, her bulging chest rising and falling rapidly, and her breathing heavy. Xu Qingzhou handed her some water with a tactful look: "You must be tired, drink some water." It was too difficult to get beaten and worry about whether she was thirsty. Song Yao took the cup and thought that this guy had some good eyesight. She drank the water in gulps and didn't bother to pay attention to this lecherous guy. Seeing that it was almost time, she went to the kitchen in her slippers to cook. "I'm here to help." Xu Qingzhou ran into the kitchen to help peel garlic. After peeling, he leaned against the door and watched her cook. Although he was beaten up and the flesh on his waist was stinging, he had already felt what he needed to feel and he was in a very good mood. All things are difficult at the beginning, next, hehe. Song Yao had a cold expression on her pretty face. She stood tall and slender, giving off an aura that said "keep away from strangers". To be honest, no matter how you looked at it, the aloof school beauty Song didn't seem to fit in the kitchen. But Xu Qingzhou had already cooked twice, and this time Song Yao insisted on doing it herself. "You, stay in the living room by yourself." Song Yao pointed at Xu Qingzhou with the onion in her hand. She didn't want to see this annoying guy for the time being.
Humph, thinking about weird things in broad daylight. Xu Qingzhou shrugged, hummed a little tune and returned to his seat, intending to continue working on his paper on quantum satellite. As far as quantum communication is concerned, entanglement is a basic resource in quantum communication. However, during the entanglement distribution process, due to channel noise, the quality of entangled photon pairs shared over long distances will decrease to a certain extent, thus affecting the quality of quantum communication. To solve this problem, Xu Qingzhou once found a very useful method when he was in his second year of doctoral studies - Xu's entangled pair purification theory. Entangled pair purification, also called entanglement distillation, is the process of extracting highly entangled quantum pairs from a group of partially entangled quantum pairs. But during this period, the purification theory was not mature, because in actual physical systems, environmental interference and noise often destroy the entangled state, making the purification process very difficult. Moreover, the current quantum purification theory requires the use of controlled NOT gates, but accurate and efficient controlled NOT gates cannot be realized with current technology. Xu Qingzhou's method does not require the use of a controlled NOT gate. As long as the initial noise is below a certain level, a small number of purely entangled pairs can be extracted. By measuring the pure entangled pairs with the same basis vector at both ends, an absolutely secure password can be obtained. The purification efficiency can theoretically be increased 15 billion times. 【 p=|bb'l+|ba'l+\bb'l'+|ba'l= 2|b'l】 This result is exactly the same as Alice's measurement using Bell states. 【When |a'l≥lal≥lbl≥lb'|.】 [From the above analysis, we can see that the success rate of teleportation is determined by the smaller value of |b'| and |b|, that is, the smaller value of the generalized Bell basis used by Alice to measure and the entanglement degree of the quantum channel. ] August 6th, early morning. Xu Qingzhou came to the research institute again. This time he did not go to the classroom, but went directly to the conference room on the second floor. There were many familiar faces here, including Academician Ma Zailiang, Wang Yigui, and He Dang, an intern like him. "Xiao Xu is here." The thin middle-aged man next to Academician Ma was talking and smiling. He was Professor Pan Jianwei, the project chief engineer. "Professor Pan, Academician Ma." Xu Qingzhou greeted them.
"Please sit down first. We will start soon." Professor Pan nodded, then lowered his head to write the formula on the manuscript paper in front of him. Xu Qingzhou looked around the conference room and finally walked over and sat down next to He Dang. He Dang greeted Xu Qingzhou: "Good morning, Junior Brother." "Good morning." Xu Qingzhou responded with a smile. At this time, Wang Yigui also came in, and as soon as he sat down, he asked anxiously: "Is everything going well over there?" "It went smoothly." Xu Qingzhou said. "Tsk tsk, you are worthy of being my junior brother. I am stuck on a calculation here, and the value I calculated is not right no matter how I look at it. If you have time later, please help me take a look." "Okay, then we'll study it after the meeting." Xu Qingzhou nodded with a smile. Standing aside, watching Dr. Wang asking Xu Qingzhou for help, He Dang sighed helplessly, feeling a little envious. As an intern as well, he could only do odd jobs at the moment. Xu Qingzhou has already become an indispensable part of the project. The meeting started at 9 o'clock. This time it was chaired by Professor Pan. Everyone reported on their respective work progress, which was basically completed on time. If there were still problems, they would discuss them. After the summary, of course, there is still work to be done in the next stage, which is mainly about the performance test of the coupling of the model and the entanglement source. "Here, the wave function of the whole system can be expressed as the tensor product of the wave functions of the two subsystems." "I have a request. When performing numerical calculations, you need to choose stable algorithms and appropriate calculation accuracy to avoid calculation instability caused by rounding errors, overflows, and other problems during the calculation process." Professor Pan paused, looked at everyone, and said: “Okay, that’s the specific framework. Now you can add to the existing framework or put forward new ideas and opinions.” Academician Ma and the others all shook their heads, and naturally no one else said anything to add. Wang Yigui saw Xu Qingzhou was deep in thought and asked in a low voice: "Junior brother, what about you?" During the time they spent together, he had witnessed the awesomeness of this junior fellow apprentice who could always come up with something new. However, because the conference room was very quiet, the sound was particularly obvious, and even Professor Pan and others looked at Xu Qingzhou. "I don't have any idea about this part of the work." Xu Qingzhou shook his head. Frankly speaking, this performance test on the quantum entanglement source is well written. It is complete with key indicators such as entanglement, stability, and transmission efficiency. Even if we look at it from the perspective of a dozen years in the future, there is nothing wrong with it. If you think about it carefully, it is normal. Both Professor Pan and Academician Ma are world-class experts in the field of quantum communications. Especially Professor Pan, how could someone who can lead the development of the world's first quantum satellite be bad? "Whoo~" Next door, seeing Xu Qingzhou shaking his head, Director He breathed a sigh of relief, and the sense of threat finally subsided a little. Yes, although I have always heard that my junior is very capable, this plan was written after discussions between two big guys, Professor Pan and Academician Ma. What could be the problem? A false alarm.
Mainly because of the influence of fellow student Deng during this period, she kept saying how amazing this junior was, which put a lot of pressure on him, a first-year doctoral intern. My junior sister is only a first-year graduate student, so it’s normal for her to be crushed. After all, he is now a first-year doctoral student and has participated in many experiments, big and small. He Dang continued to provide psychological comfort. Then, he heard Xu Qingzhou say: "However, I wrote a paper that contains some ideas about quantum entanglement, including quantum secure communication of entangled photon pairs, hidden transmission of quantum states, and manipulation of entangled photon pairs." "In addition, when I was studying quantum purification theory, I deduced an efficient and accurate method, which should be helpful for our future experiments." As he spoke, Xu Qingzhou handed the USB drive to Professor Pan. He Dang: “.” Professor Pan nodded slightly and inserted the USB drive into the computer. He was looking forward to the new ideas that the young man mentioned. Academician Ma did not have high expectations for things like the hidden transmission of quantum states that Xu Qingzhou had mentioned earlier, because he and Professor Pan were already top experts in this field. We should support young people's enterprising spirit. No matter what new ideas this little guy comes up with, they should be encouraged. As for the entanglement and purification, there is currently no effective way to deal with this thing, and he doesn't think that Xu Qingzhou has made any substantial progress. The other people also smiled faintly, relaxed, and curiously stared at the projection in front of them, talking about quantum entanglement in front of Professor Pan and Academician Ma. Young man, you are a little bit arrogant. Dr. Wang sighed inwardly, regretting a little that he had asked his junior fellow student just now. If he hadn't asked, his junior fellow student might not have brought up that paper at the meeting. It's like waving a sword in front of Guan Gong. Since the computer was connected to the projector, the paper soon appeared in front of everyone. 【Quantum entanglement and quantum manipulation】 【Abstract: This paper reviews the basic principles, methods, technical means and applications of quantum communication, and introduces the implicit transmission of quantum states based on quantum entanglement and the manipulation of entangled photon pairs.】 【Keywords: quantum communication, quantum key distribution, quantum teleportation, manipulation of entangled photons】 (End of this chapter)