"I did think about this question and have a preliminary understanding of the answer to this question." Junxin replied, "But as Professor Witten said, so far, we have not determined the number of these models and the conditions for each to be established, so the answer to this question is only speculation so far." ”

"Then tell me about it!" Professor Strominger urged.

"Okay, Professor!" Junxin nodded and said, "I have the following thoughts on this question, if my idea is not wrong, then superstring theory will continue in the following solutions. ”

"The first way I think about it is that the number of models that are represented by these superstring theories is not too many, no more than ten or even five or six, so I can think about it like this, are all the models actually unified in a large model framework? Are these models just a special case of this larger model or theory, or are they the values of their different limit conditions? ”

"The second idea, which is also the model of string theory, can be assumed in the case of a limited number of models, and in the case of no more than ten models at most, that among all the models or theories, there is actually only one model that can be established, and the reason why these models are established is that there are some inherent defects or regulations in string theory, but we have not yet discovered, which leads to the self-consistency of other models or theories."

"The third idea, under the same condition as above, is that the starting point of superstring theory itself is quantum mechanics, and then it is through various settings that superstring theory itself conforms to the theory of relativity, so is there a situation where superstring theory itself has other assumptions, and these assumptions are also in a sense in line with the requirements of the theory of relativity, but we don't know such assumptions. Under this assumption, there may be a single and feasible model that makes superstring theory completely self-consistent. ”

"The above are the three directions I have considered, of course, there may be other possibilities, but I haven't thought about them one by one, what do you think?" Junxin asked.

Witten, Strominger, Horowitz and Candela looked at each other, they hadn't thought about these things at all, so naturally there was nothing good to suggest.

After waiting for a while, the eldest Professor Candela said, "I have a general idea of what you think, but I have a question for you, your thinking direction is based on a limited number of models or theories, can you tell me why?" ”

"This question is very simple, because I have studied the Yang-Mills equation in detail, and although it is impossible to completely solve this equation, from my research on this equation, it is very difficult to fully satisfy the conditions of this equation. In other words, it is very difficult to satisfy the self-consistency of superstring theory, and I don't think there are many models to be found. According to my research, no more than ten models will hold up at most. ”

"Is that so? So why don't you look at the other models that come next? Professor Witten asked.

Junxin shook his head and said, "That's not what I'm going to do, because I'm not sure if my research is correct. ”

"Why?"

"If the Young-Mills equation is completely solved, then I still dare to make this guarantee, but unfortunately, although this equation has been proven to be correct, it cannot be completely solved, so many questions cannot be judged with certainty. I can only draw conclusions on this question based on my own research on the Yang-Mills equation and use my own judgment. Whether others are convinced of this reason, I can't guarantee it. Jun Xin said a little helplessly.

"I trust your judgment, but my current work is still focused on the exploration of superstring theoretical models, because for me, it will take a lot of energy for me to study what is possible under the current conditions without fully mastering superstrings." Horowitz said with a shrug.

"What do you think, Professor Witten?" Junxin asked.

Witten pondered for a while and said, "I have a question, it takes a lot of math to make assumptions under the condition that the Yang-Mills equation is true, right?" Can I assume that these judgments and assumptions of yours are based on your mathematical thinking and calculations? ”

"Yes!"

"Well, then, I think it's necessary for me to look into the various self-consistent conditions of the Yang-Mills equation!" Professor Witten said with a smile.

"You're saying you're interested in the first of the directions I've come up with, right?" Jun Xin couldn't help but marvel in his heart, Professor Witten was worthy of being the leader of the study of superstring theory in his previous life, and he still embarked on the original path.

"Well, I think this direction is the most likely!" Professor Witten said with a smile.

"Professor Candela, what about you?" Jun Xin stopped talking, but asked Professor Candela again.

Professor Candela shook his head and said, "I still have my own research work, and I haven't thought about the next research direction of superstring theory for the time being. In the future, I will probably focus on the existing superstring theoretical model to solve some physics problems with the superstring theoretical model. ”

Without waiting for Junxin to ask, Professor Strominger, who had not spoken much, said: "My idea is actually similar to Witten, but the slight difference is that the development of superstrings may be a little too fast, and some basic research on superstring theory may not be too good, I want to work with Professor Schwartz to engage in the research of basic work on superstring theory, what do you think?" ”

Jun Xin smiled and waved his hand: "I don't have anything to say here, in fact, I have already started to study this problem, but the difference is that my research direction probably started from mathematics." Whatever these three directions of research are, at heart, the future of theoretical research will probably be the same as the Yang-Mills equation, which will focus on mathematics, and these are my strengths. ”

Professor Witten smiled and said, "It seems that the division of labor between the few of us is still very clear, so it's okay, we can talk to each other in the future and ask if there is one." This may speed up the progress of our research. After a pause, Professor Witten continued, "Then let's discuss the problems we have encountered during this period of time and the ideas for solving them!" Professor Candela, how about starting with you? ”