Translator: Henyee Translations Editor: Henyee Translations
Time passed by quickly.
On April 20th, Professor Lu Shenjian returned to the University of Jin Ling from a meeting in Shanghai and called Lu Zhou to his office.
When Lu Zhou walked in, the old man smiled and asked, “How’s the preparation going?”
Lu Zhou replied, “Almost… Please give mercy.”
Professor Lu Shenjian, “Almost? Okay then, I’ll test you a few questions.”
He pulled out his drawer and took out an A4 paper. He then placed the paper on the desk.
“Write on this.”
Lu Zhou took a pen and when he looked at the question, his eyebrows twitched.
There were three questions on the paper.
They all looked difficult…
Professor Lu Shenjian smiled and asked, “What, you don’t understand?”
Lu Zhou smiled and looked at the questions as he said, “No of course not, it just doesn’t look easy.”
Professor Lu Shenjian smiled and did not respond. Instead, he crossed his legs and waited patiently.
Easy?
It wouldn’t be interesting if it was easy.
After all, he was an academician.
This question was not intended for master’s students, it was for PhD students.
If Lu Zhou could solve two questions, it would count as a pass. If he could solve all three, that would be excellent.
His four PhD students could solve all three questions.
While Professor Lu Shenjian was waiting for Lu Zhou to do the test, Lu Zhou quickly skimmed through the three questions. The first question looked the easiest.
It was about group theory.
However, it was not mathematics group theory, but the application of group theory in quantum mechanics.
Since the “group theory” branch of mathematics was created independently by mathematicians long before the emergence of “quantum mechanics”, it was unlike “calculus” which was founded by physicists and mathematicians. Therefore, group theory was an “important product” for physicists. It was difficult to learn and not easy to use.
For a “mathematician” like Lu Zhou, however, it was not too difficult.
[A group theory explanation of the accidental degeneracy of hydrogen atomic energy levels]
The question was short, but it contained a lot of information.
The phenomenon of degeneracy in hydrogen atoms higher than ordinary atoms was called “accidental degeneracy.” However, traditional quantum mechanics cannot explain the phenomenon of accidental degeneracy without the use of group theory.
Lu Zhou closed his eyes and recalled his quantum mechanics knowledge.
Then, he built a mathematical model in his head…
Lu Zhou opened his eyes and after taking a deep breath, he picked up the pen and started to write on the paper.
[Let the hydrogen atom Hamiltonian be H=P2/2μ-Ze2/r…]
[In the case of Coulomb potential, there is a Runge vector in the system, recorded as M’=…]
[The eigenvalue of the group Casimir operator C=…]
[…]
When Professor Lu Shenjian saw the speed of Lu Zhou answering the question, he was surprised.
He thought that Lu Zhou would take at least 20 minutes to do the question.
Moreover, Lu Zhou answered it correctly.
He planned to insult Lu Zhou when he could not solve the question, but that was no longer needed.
[For the energy level E(n+1) and the quantum number (n, 1), the degeneracy is Σ2(l+1)=n2…]
When Professor Lu saw the answer, he nodded in his mind.
First question, correct!
Lu Zhou did not notice Professor Lu’s expressions as he was focused on doing the second question.
The second question was about the problems of Dirac’s cavity theory in quantum field theory. It tested his understanding of Dirac’s equation and some theoretical knowledge about field theory.
Lu Zhou was not afraid of this kind of pure theoretical question. With the help of the focus capsules, he remembered all of his textbook readings.
For him, this question was free marks.
Lu Zhou quickly picked up the pen and answered the question.
When Professor Lu saw Lu Zhou answering the question, a slight smile appeared on his face.
He was right.
This kid was talented in theoretical physics, even more than his four PhD students.
If the University had not given Lu Zhou a personal talent development plan, he would have wanted Lu Zhou to study a PhD with him as well.
Of course, he still supported Lu Zhou’s talent plan.
Lu Zhou solved the second question and quickly moved on to the third question.
When he saw the third question, he was stunned for a second.
The third question was about “string theory”.
The so-called string theory tried to solve the two main physics theories of incompatibility. It was the contradiction between quantum mechanics and general relativity. The string theory wanted to describe the whole universe, and it was known as the legendary “Grand Unified Theory”.
This theory had a lot to do with mathematics.
Venezzino, who worked at CERN 1 , originally wanted to find a mathematical formula that described the strong forces in the nucleus. As a result, he found the Euler formula in an old maths book. This formula unexpectedly successfully described the strong force.
Even though it sounded fake, it was just a weird coincidence.
Like this, string theory was born.
The later wave of string theory such as superstring theory and the famous M theory of “unification of rivers and lakes” as proposed by Edward Witten were also developed.
The ultimate goal of physics was to establish a “Grand unification theory”.
However, China’s research on string theory was at an awkward stage.
Condensed matter physics itself stood on the opposite side of theoretical physics. The theoretical physics community was reluctant to accept this “mathematics freak”.
Even the leader of China’s theoretical physics and one of the most influential physicists in the world, Mr. Yang Lao, expressed his disapproval of string theory. On the contrary, the Chinese mathematics community accepted the proposal of string theory.
However, what confused Lu Zhou was that the third question asked him his opinion on string theory.
Opinion?
Opinion toward the theory? Or opinion toward the development of the theory?
Is this a subjective question?
Lu Zhou paused for a long time, he felt lost.