The first stage is to supplement basic professional knowledge. Such as advanced quantum mechanics, group theory and quantum optics. This stage is mainly about absorbing knowledge, almost eclectic. Avoid questioning book knowledge, just like a child, you can concentrate on listening to adult stories and listen with relish.

The second stage is to use the knowledge flexibly. For example, many people have studied calculus and complex function, but whether they can skillfully apply it in the future depends on whether the knowledge learned at this stage is flexible and profound.

The third stage is asking questions. Generally speaking, the proposal of a brand-new question has no logical connection with previous theories and knowledge, so the question itself belongs to the category of creation, which is different from the rational thinking of the general causal chain and usually shows as an inspiration. After the above two stages, graduate students have acquired sufficient professional knowledge background and the ability to use knowledge flexibly. What they need is a clear sense of problems. Being able to question and discover new problems is the embodiment of their ability.

The fourth stage is enlightenment. How to see the essence from the phenomenon and how to abstract the theory to solve the problem from the specific problem? This is even more necessary to have an epiphany. After finding a solution to the problem, the situation was completely new. It is a feeling of sudden realization, and all previous knowledge can be applied here. However, this kind of knowledge has taken on a new look at this time, and it is full of flowers.

The fifth stage is the promotion from point to surface. State, refine, abstract, simplify knowledge and reveal beauty.

The sixth stage is to return to ignorance.