The Science Fiction World of Xueba

Pang Xuelin chatted with Catherine Murphy all afternoon.

This woman is worthy of being a senior reporter of Time Magazine, and she is very good at controlling the rhythm of the chat.

From mathematics to life, from life to career, the interview, which lasted for more than three hours, ended at 4:30 in the afternoon.

After that, Pang Xuelin cooperated with the photographer of Time Magazine to pose for more than half an hour to complete the pose.

"Mr. Pang, thank you very much for your cooperation today. May I have the honor to treat you to dinner tonight?"

Murphy stood up and shook hands with Pang Xuelin, scratched Pang Xuelin's palm with the tip of his little finger without any trace, and looked at Pang Xuelin with a half-smile.

Pang Xuelin withdrew his hand calmly, and was about to refuse aloud when Edward Witten hurried in at the door of the coffee shop.

"Mr. Pang, I'm sorry I didn't bother you?"

Edward Witten looked eager.

"Professor Witten, it's okay, I just finished the interview, what's wrong?"

Pang Xuelin was puzzled.

Witten said: "About Ponzi geometry, I want to chat with you, I wonder if it's convenient for you now?"

Pang Xuelin shrugged at Catherine Murphy, smiled apologetically and said, "Ms. Murphy, I'm sorry, it seems that I can't have dinner with you tonight."

Murphy raised his eyebrows, wrote down a series of numbers in the notebook, tore off the page and handed it to Pang Xuelin, and said with a smile: "This is my mobile phone number, I will stay in Princeton for a few days , if you have time, welcome to find me!"

After finishing speaking, Murphy picked up the recording pen and backpack, winked at Pang Xuelin, and said to Edward Witten, "Professor Witten, I won't bother you and Teacher Pang."

this woman...

Pang Xuelin shook his head and smiled, and said to Witten, "Professor Witten, what can I do for you?"

Edward Witten looked around and said, "Mr. Pang, let's find a quiet place to chat."

Pang Xuelin said: "Okay, go to my room!"

Came to the executive suite where Pang Xuelin lived,

The two sat down in the office area.

Geng Huan gave them a cup of coffee each, and then quietly exited the room.

Witten took out a stack of manuscript paper full of formulas from the small bag he carried, and said, "Mr. Pang, do you know superstring theory?"

Pang Xuelin was slightly taken aback, his eyes narrowed slightly.

The most important reason why Edward Witten has such a famous name in the field of theoretical physics is that he proposed M theory in 1995 on the basis of superstring theory, combining five superstring theories and eleven The theory of supergravity in three-dimensional space is unified into a single mathematical structure.

This work set off the second superstring revolution. In later generations, M theory is considered to be the most promising ultimate theory to solve the essential interaction relationship between matter and energy.

But at this time, Edward Witten should not have completed the research work on M theory. Could it be that his own Ponzi geometry gave him some inspiration?

Pang Xuelin said: "I probably know something. In physics, one of the basic problems to be solved is how to realize the quantization of gravity and how to combine gravity with the other three basic interactions in nature (electromagnetic force, strong interaction, weak interaction), superstring theory is currently the only theory that can achieve the above requirements."

Witten was a little surprised and said: "Great, Pang, I think you also know that although superstring theory seems to be able to describe the ultimate unity of interactions in nature, there are still several problems. First, there are currently five A self-consistent perturbative string theory in the sense of quantum mechanics, they are two IIA and IIB, a hybrid string theory whose gauge is Apin(32)/Z2, a hybrid string theory whose gauge group is E8×E8 and A Type I string theory whose specification is SO(32). They are equivalent in the physical sense, and we cannot theoretically choose one of them while excluding the existence of the other four superstring theories."

"Secondly, the self-consistency of the five perturbation strings requires ten-dimensional space-time and space-time supersymmetry, and its natural scalar energy is 10^19GeV. In the foreseeable future, it is impossible for us to create such a high-energy accelerator pair. String theory is a direct test. Therefore, the minimum test requirement is that some kind of perturbative string theory can give observable physics in four-dimensional space-time, such as the standard model of particle physics...”

"The third question is that for an ultimate theory describing all the physical laws of nature, apart from some possible basic constants such as the speed of light, Planck's constant and string tension plus possible initial values ​​or boundary conditions, other quantities should be determined by determined by the dynamics of the theory. In particular, the vacuum state of the theory should be determined by its dynamics."

"But the perturbative string theory assumes that the space-time is flat from the beginning, and requires the string interaction to be small, so that the string perturbation unfolding is effective. These assumptions are contrary to the requirements of the ultimate theory. Therefore, the five existing Perturbative string theory is a limit theory, so it is unlikely to be the ultimate theory."

"Fourth, from the perspective of perturbative string theory, the eleven-dimensional supergravity theory seems to have nothing to do with describing the real world. We know that the low-energy limit of the five perturbative string theories gives the corresponding supergravity theory, while the lower-dimensional The supergravity theory corresponds to the compacted superstring low-energy theory. If the perturbed string theory is really the ultimate theory, then we have no way to explain the existence of the eleven-dimensional supergraviton.”

"But if we regard the one-dimensional spatial dimension of the eleven-dimensional space-time as an extremely small circle, the eleven-dimensional supergravity will give one of the low-energy effective theories of superstrings. The radius of this small circle is the same as The interaction strength of this string theory is proportional. From this we can see that the eleven-dimensional supergravity should be related to the low-energy theory of this non-perturbative theory of strings. In other words, we only understand the non-perturbative theory of string theory properties to explain eleven-dimensional supergravity."

Pang Xuelin said with great interest: "Professor Witten, what do you mean...?"

Edward Witten's eyes sparkled, and he said: "I have been looking for a brand new theory for the past few years, unifying the five superstring theories and the eleven-dimensional supergravity theory, but I have never been able to find a suitable mathematical tool To describe it, but through the research on Ponzi geometry in the past two days, I vaguely feel the dawn of a new theory. But my research on Ponzi geometry is still quite shallow, I need your help, or, we cooperate in research, What do you think about working together to find a new ultimate theory?"

Pang Xuelin looked into Edward Witten's eyes, pondered for a moment, stretched out his hand and said with a smile: "Happy cooperation!"