In Liu Feng's view, this question seems to be very difficult, if it is just an ordinary graduate student, it is really possible to be stumped, but it is a pity that he has already been out of the category of 'general', with the advantage of 'never forgetting' and a somewhat smart mind, he still writes with a pen, without thinking too much time!

In the third question, Wang Yifang thought that Liu Fengfeng would spend about ten minutes thinking

Unexpectedly, Liu Feng only paused, and after looking at the topic twice, he started to write.

Good boy, Lao Tzu really didn't look away! A smile of relief finally appeared on his face.

Obviously, Liu Feng's answer to the question is completely correct!

This kid is really a good seedling for studying high-energy physics. With the talent he is showing now, I am afraid that he has a better chance of inheriting his mantle than several of his senior brothers...... Academician Wang sighed with emotion.

And just as he sighed, Liu Feng had already come to the level of the fourth question.

Compared with the third question, this question is even more difficult at the hellish level, and it is a question about "quantum entanglement".

The so-called quantum entanglement is a quantum mechanical phenomenon, a wave proposed by Einstein, Podolsky and Rosen in 195.

By definition, quantum entanglement is a phenomenon in which particles interact with each other in a system composed of two or more particles, which describes the entanglement of two particles with each other, even if they are far apart, the behavior of one particle will affect the state of the other, and when one of them is manipulated and the state changes, the other will immediately change the corresponding state.

Speaking of which, as one of the research directions of high-energy physics, quantum mechanics is now a research frontier in the field of modern physics, and the research of quantum mechanics has not stagnated in recent years, but has made great progress and achieved extremely remarkable results, both at home and abroad.

In particular, the competition between China and foreign countries in this regard is even more like your singing and our debut.

Since 2000, when the National Bureau of Standards of the People's Republic of China realized the entanglement state of four ions on the ion trap system, researchers from the Department of Quantum Physics and Quantum Information Research of the National Laboratory for Physical Sciences at the Microscale broke this record in 04 and successfully realized the manipulation of five-photon entanglement for the first time in the world.

Of course, the national Yankees must not be convinced by the achievements of Huaguo, so at the end of 05, the National Bureau of Standards and the Innsbruck team of Austria announced that they had achieved the entanglement state of six and eight ions respectively, and had maintained this record for 5 years.

It was not until this year that the research group of Professor Li Chuanfeng and Professor Huang Yunfeng of the Key Laboratory of Quantum Information of the Chinese Academy of Sciences, under the leadership of Academician Guo Guangcan, successfully prepared the eight-photon entangled state--GHz state, and further used the entangled state to complete the eight-port quantum communication complexity experiment.

At this point, the realization of quantum entanglement and distribution technology is just around the corner, and it may not be long before the information technology revolution based on quantum communication will come.

However, what made Liu Feng a little puzzled was that Boss Wang's research direction was not quantum mechanics, so why should he take such a question? Could it be that even Boss Wang was not optimistic about the direction of high-energy physics that was purely focused on finding particles?

If this is the case, Liu Feng feels awe-inspiring.

The development of high-energy physics has not been shocking until now, but the development of quantum physics, which was not appreciated by most people before, has become more and more prosperous, which makes him quite disappointed when he wants to find and prove the research direction of new particles.

So, the tip of the pen stopped on the paper for a long time, and he was a little confused for a while after passing all the way to the last level.

Seeing that Liu Feng hadn't started writing for a long time, Academician Wang asked with a smile. ．

"I've done the first three questions, why can't I do the last one?

After staring at the question for a while, Liu Feng refused to admit defeat, in fact, he already knew the answer to this question, but he still had some questions he wanted to ask Academician Wang, raised his head and asked, "Professor, have you also studied quantum entanglement?"

"Hmm, I'm just asking you to talk about your opinion, what do you care if I have studied it?" Academician Wang smiled and said, "If you can't do it, it's nothing, you just say it, don't care about my opinion." ”

Liu Feng shook his head: "For quantum mechanics, to be honest, I don't have many opinions...... Wait a minute, let me finish this problem first!"

After speaking, Liu Feng started writing directly, and wrote on the answer sheet.

After a while, the work was called a day and the paper was handed in.

"Look at it, I'm right. ”

Academician Wang was stunned.

Originally, he was ready for Liu Feng to give up answering the question, after all, although he only answered the same three questions, compared to his senior brothers, he was far better in answering the question;

Looking at Liu Feng's answer carefully, whether it is the idea of answering the question or the specific solution, it coincides with himself, not to mention the final answer, which is naturally very correct.

It seems that this kid is really a genius level person!

With a sigh, Academician Wang was both happy and deeply stressed - such a genius student, don't be spoiled by yourself!

"Very good, it seems that your kid is also very solid in the basic skills of quantum mechanics, which makes me even more worry-free. ”

"Professor, what do you mean by that?"

Liu Feng asked suspiciously.

"In short, you don't care about it for now, and you will understand later. Academician Wang didn't want to continue to dwell on this, "Let's talk about your views on quantum mechanics!"

"This ...... Well, in that case, I'll start with a casual touch of my personal opinion. Liu Fengzhi is not a person who does not know how to advance and retreat, so he can only bury his doubts in his heart and talk about quantum mechanics instead.

"Quantum mechanics, especially quantum entanglement, as a physical resource, plays an important role in all aspects of quantum information, such as quantum teleportation, quantum key distribution, quantum computing, etc. However, due to the limitations of experimental conditions and the influence of unavoidable environmental noise, not all of the prepared entangled states are maximally entangled.

On the other hand, the pure entangled state will also degenerate into a mixed state due to the decoherence of the environment, and the use of this hybrid entangled state for quantum communication and quantum computing will lead to information distortion, and in order to achieve better quantum communication or quantum computing effect, it is necessary to purify the hybrid entangled state into a pure entangled state or close to a pure entangled state through entanglement purification technology.

Therefore, how to purify high-quality quantum entangled states is an important topic in quantum information research.

The common quantum entangled state applications, such as quantum communication applied to quantum state teleportation, quantum computing applied to quantum computers, quantum computing has serious technical challenges in the implementation of quantum computing, and the realization of this problem needs to solve three other problems - quantum algorithms, quantum coding, and the physical system of quantum computing. ”

Academician Wang smiled and asked, "So you also think that the development of quantum mechanics is also urgent?"

"Whether it's urgent or not is not something I can decide," Lu Zhou shook his head and replied, "At least, in these aspects, the development prospects of quantum mechanics are very bright!"

The index finger tapped lightly on the table, and after a long while, Academician Wang nodded slowly.

"Not bad. ”

Nice to mean?

Liu Feng was confused.

"Professor, then I should have passed this matter of being turned into a regular in advance?"

Academician Wang nodded and shook his head again.

"It can be seen that you kid has really put in some effort in the past few days! It's just that the matter of turning a positive is not busy for the time being, I will give you an important task first, and in two days, someone will come to us to do a collision experiment?

Liu Feng: ......

Reception?

Isn't it just a miscellaneous person?

Said that if you pass the assessment, you will become a regular?

Someone else is doing experiments, what the hell am I receiving?

"Hehe, don't be unhappy, you kid, many people rush to do this and don't have a chance!" Seeing that Liu Feng seemed to be a little emotional, Academician Wang smiled and said meaningfully, "I'll tell you an important news, I came to us to do experiments, but I was the former winner of the Dynamite Award......"