After Transmigrating through Books, I Transmigrated Back

Chapter 17: Quantum physics

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Before being discovered by SSE, Xu Qiao had absolutely no background in art and was just a science and engineering student. Singing, dancing, acting, and running variety shows were too difficult for him, who had only performed on stage since kindergarten.

Therefore, he has always been known as a "vase". But Xu Qiao's lack of talent does not mean that he is not smart. When he took the college entrance examination, he was admitted to T University, one of the best science and engineering colleges, with high scores.

When Yang Hui signed him, she also wanted to take advantage of Xu Qiao's professional background and create an image for him as a top student who graduated from a prestigious school.

However, Xu Qiao did not want to take advantage of his alma mater's reputation. He was worried that he would bring shame to his alma mater, so he was unwilling to cooperate, and the matter was eventually dropped.

You still have to go to school and get your diploma and degree certificate.

Xu Qiao looked at the school calendar. It was almost the end of the semester. In the next week or two, all courses would end one after another, and the final exams would follow.

Because he signed a contract with SSE this semester, he had less than half a month of classes at most.

Although he had asked for leave from the counselor, the professional course teachers were not so easy to talk to. Xu Qiao's professional course teachers were strict and old-fashioned, and were notoriously ruthless. If you were absent once, your attendance score would be deducted. If you were absent too many times, you would not even think about getting your regular score.

Xu Qiao is studying mathematics, and the final grade for each course is calculated based on 40% of the regular score and 60% of the final exam score.

Having given up hope for his regular grades, Xu Qiao thought about it and decided that if he wanted to avoid failing the course, he could only try to get more points in the final exam.

Xu Qiao packed up, went downstairs and took a taxi to T University.

There was no professional course today, but there was an elective course. It was a course related to communications engineering that he had taken to get the required credits for graduation. The lecturer was a well-respected professor in the field of communications and a member of the National Academy of Engineering.

The end of the semester is always the time when the attendance rate is the highest. When Xu Qiao walked into the classroom, there were still more than ten minutes before the class started. The seats were already densely packed, and only the first row, where the professor could listen to his lectures up close, was still empty.

The professor hadn't arrived yet and the classroom was very noisy. Xu Qiao moved his ears and heard many people complaining that they regretted choosing this course.

"I review two lines in one night, read one sentence, and forget three lines."

"It's over, it's over. Why did I choose this course? Professor Sun is so stingy with grades. Why don't I take an image and temperament cultivation course? I can just walk on the catwalk and dance at the end of the semester and get a high score. Isn't that great?"

Many college teachers offer elective courses in order to meet the performance standards required by the school. In order to attract students to take his course, the grades are often very lenient.

But Professor Sun is highly respected and has a high status. Even the president dare not put on airs in front of him. He does not need to teach elective courses for performance evaluation. He teaches courses just to satisfy his interest in teaching. He is notoriously ruthless in giving grades.

Even so, there are still a lot of students who choose his classes out of admiration for him, only to wail with regret at the end of the semester.

"Stop talking. When the professor asked questions in this class, we raised our hands and answered them enthusiastically. What if he remembered our names and gave us high marks? Eh? Is that Xu Qiao?" The male student who was chatting enthusiastically glanced at Xu Qiao who walked into the classroom, and his voice suddenly lowered.

Xu Qiao took a quick look and saw that there were no empty seats in the back row. After hesitating for a moment, he sat down in the first row.

In the entire first row, there was only that lonely figure, which made him stand out.

The students around him saw him coming over and sitting down, and started discussing in a low voice.

"Oh my god, it's really Xu Qiao. He actually came to class."

"You can't be a star anymore, so you come back to study in shame?"

"But to be honest, it would be hard for him to graduate successfully after missing classes for so long. I think he will most likely have to delay graduation."

Most of the students in the classroom have never had the experience of close contact with a celebrity. Although Xu Qiao is unknown and has a bad reputation, it does not stop them from watching the fun. They stare at the figure in the first row and discuss it at will.

Amid the noise, Professor Sun walked into the classroom.

The old man was nearly 70 years old, with a straight back, vigorous spirit, and a breeze in his steps. He glanced around the classroom and put the roll call aside: "Oh, it's the end of the semester, and there are quite a few people here. I see that everyone is here, so I won't take roll call."

Many people wailed again. It was rare that they didn't call the roll, and if they didn't call the roll, they wouldn't get any attendance points.

Professor Sun took a piece of chalk and wrote the four characters "quantum communication" on the blackboard. After writing, he turned around and pointed at the four characters and said, "Come on, let's talk about quantum communication today. Everyone knows that I am engaged in communication engineering. When talking about communication engineering, quantum communication is unavoidable."

"Quantum communication has two main sources: one is a high-frequency single-photon source, and the other is an entangled light source..."

Professor Sun was speaking on the podium, and many students were still looking at Xu Qiao in the front row and whispering. Professor Sun looked back and forth at the students who were talking, but they were unaware and their voices were getting louder and louder.

"High-frequency single-photon source. Our school also has the conditions to conduct experiments. It is to attenuate the high-frequency laser pulse to less than a single photon—"

Seeing that the person who was talking didn't know how to stop, Professor Sun stretched out his voice and threw the lesson plan on the table with a clanging sound. Many people were startled and fell silent.

The old professor was not young anymore, but his voice was still loud: "Who wants to speak? Should I speak or you? Come on, whoever wants to speak, I'll give him the microphone."

The classroom was quiet.

Xu Qiao, who had been lowering his head, couldn't help but raise his head and met Professor Sun's unpleasant eyes.

Xu Qiao was stunned, not knowing how he had offended the professor, and blinked innocently.

Professor Sun snorted coldly. When the group of students were talking, their eyes kept turning to Xu Qiao, so he knew they were talking about Xu Qiao. He always hated students who didn't follow the class rules, and he also started to dislike Xu Qiao.

Professor Sun picked up the poor teaching plan that he had thrown on the table, raised it towards Xu Qiao, and motioned him to stand up: "Student, what is your name?"

Xu Qiao answered obediently: "Xu Qiao."

Professor Sun flipped through the roster and sneered, "I was wondering why you looked so unfamiliar. You've only been to my class twice this semester."

He walked up to Xu Qiao and looked him up and down: "You are still a senior. You are already a senior, and this is your attitude in class? If you don't want to take this course, then don't choose it. Why bother me and make things difficult for yourself?"

Xu Qiao's eyes were clear and his voice was sincere: "Professor, I want to go."

Professor Sun was amused: "Want to go? Then what have you learned?"

After a pause, Professor Sun looked around the classroom and returned his gaze to Xu Qiao: "Today's class has students from freshman to senior year. Come on, Xu Qiao, as a senior, tell the juniors why we are doing quantum communication."

Is this the on-site assessment

The students who dared not speak looked at the two of them, thinking that Xu Qiao had angered the old man and was in trouble. Xu Qiao's major was mathematics, and he had not attended classes much this semester. It would be strange if he could talk about the content related to communication engineering.

Many students know that Professor Sun is a very easy-going person. If you had sincerely apologized and admitted your mistake, he would not have made things difficult for you. But if you insist on being stubborn and arguing with him, who else would he make things difficult for

Xu Qiao was not afraid of Professor Sun's "I'm just making things difficult for you" look, and spoke without thinking: "Quantum communication is essentially an applied science that combines cryptography and quantum physics." Coincidentally, in the world of books, Xu Qiao has studied both aspects.

"Traditional cryptography follows the symmetric encryption concept, where encryption and decryption are mutually inverse and extremely easy to crack. The widely used RSA, or asymmetric encryption, is based on the mathematical fact that 'it is easy to multiply two prime numbers, but it is difficult to factorize the product and restore it to two prime numbers', making decryption much more difficult."

Xu Qiao paused, looking relaxed: "However, as long as the computer's performance is sufficient, RSA can also be cracked."

"Since everything can be cracked, there is no such thing as absolute information security. Mr. Shannon summarized that an 'absolutely secure password' must meet the following conditions: the password is truly random and is used only once, and the plaintext and ciphertext are of equal length. It sounds almost impossible to meet, but the laws of the quantum world make it possible."

Xu Qiao once did scientific research in a certain book-traveling world, specializing in quantum physics. The basic physics in that world was several decades ahead of today.

In terms of academic level, Professor Sun in front of him may not be better than him.

Xu Qiao spoke at a steady pace, talking about his views on quantum physics and how it should be better applied in communications engineering.

Professor Sun wanted to embarrass him on purpose, but when he saw Xu Qiao's words were quite convincing at first, he couldn't help but sneer. As Xu Qiao talked more and more, he began to feel that something was wrong, and the disdainful smile on his face gradually disappeared.

So the students who didn't dare to speak saw that Professor Sun's gaze as he looked at Xu Qiao changed from anger to eagerness.

The eagerness was as strong as fire, three times stronger than when a young man sees his beloved girl.

Professor Sun was intoxicated by Xu Qiao's voice, as if he was listening to a classical concert.

Xu Qiao occasionally slowed down his speech to soothe his throat, and Professor Sun looked at him with dissatisfaction, like a child whose candy was taken away, urging him to speak faster. He would also interrupt from time to time and ask a few questions that he didn't quite understand.

The two of them did not have the attitude of teacher and student at all. From the side, it looked like two academic giants discussing cutting-edge academic issues.

The other students looked at each other, not daring to believe their eyes: Was this a dream? Didn't Xu Qiao attend class for a long time? How did he know all this

The class passed with Xu Qiao and Professor Sun discussing together.

When the bell rang, Professor Sun seemed to have just woken up from a dream. He was still not satisfied. He looked at Xu Qiao with eyes full of love: "You said that you are a kid with a very high academic level, but why don't you show it? If I don't ask you a question today, will you keep it hidden? Well, I think this won't work. If you have the ability, you should work hard to walk on this path!"

Xu Qiao smiled but didn't respond.

"Xu Qiao, do you want to take the postgraduate entrance examination? Really, if you choose me and pass the national line, I will definitely accept you!"

Hearing Professor Sun say this, the students beside him had even more complicated expressions.

Professor Sun is an academician of the Chinese Academy of Engineering. Apart from occasionally coming to the school to teach, he spends most of his time leading projects and conducting scientific research. He has not accepted graduate students for many years, and he only takes on doctoral students from time to time. This time, he actually took the initiative to extend an olive branch to Xu Qiao. This is something that many people would beg for!

Looking at Professor Sun's expectant eyes, Xu Qiao paused before saying, "Professor, I don't plan to take this path at the moment, but if you need help with any work, you can call me."

He actually refused?

The students who were paying attention to the conversation between the two were almost kneeling down to Xu Qiao.

Xu Qiao's consideration is that science has a significant impact on civilization. He is worried that the theoretical results in his mind, which should have appeared decades later, will appear ahead of time, which will trigger a huge butterfly effect.

Professor Sun felt a little regretful and looked at Xu Qiao reluctantly. After much persuasion, the two of them exchanged contact information.

The students who took Professor Sun’s class today all felt disillusioned.

The fantasy of the human world.

In the evening, this class video was submitted to a science influencer on Weibo with millions of followers. After the influencer posted it, it was forwarded by several entertainment accounts, which immediately caused quite a stir.

The most cutting-edge science: fan-submitted videos. Xu Qiao, a former member of the band Chasing Light, discussed quantum communication with his lecturer in class. What do you think of this

The video below was obviously filmed secretly with a mobile phone. The picture quality is not high and the camera is shaking. The sound quality is good, and the conversation between Xu Qiao and Professor Sun can be clearly heard.

Xu Qiao’s haters rushed in immediately.

There are so many complaints, I'm too lazy to even click on the video, it's obvious it's hype.

Oh, are you colluding with the lecturer to create a nerd image? How much money did you give me? Just take me and share it.

I hate xjb's character creation the most. I'll just wait and see when your character collapses.

enmmm, those who say that there was collusion to hype up the persona suggest that you check the identity of this professor. He is an academician of the Chinese Academy of Engineering and a big shot in the field of communications. Do you think such a person would act as a stand-in for a small celebrity

A student from the Communication Engineering Department of T University passed by and said that his legs were shaking and he wanted to kneel down when he saw Academician Sun.

People say that he is hyping up his academic ace persona. If they wanted to hype him up, they would have done it long ago. He actually studied hard and got into T University with high scores.

If you say others are not good enough, why don’t you try applying to T University

I never knew Xu Qiao was from T University... To be honest, I have a good impression of him just for this reason. If other celebrities studied at such a prestigious university and had such academic qualifications, I don't know how they would hype it up. Xu Qiao has never used his school to promote himself.

I'm so shocked! Academician Sun took the initiative to accept him as a graduate student, but he actually refused!

I am a physics major passing by, and I watched this video several times. What Xu Qiao said was really thought-provoking, and I felt quite inspired. Thank you!

+1 for physics majors. Just now, the major teacher asked everyone in the group to watch Xu Qiao's video three times. We will talk about it in class tomorrow...