After the lightning and thunder, the rain outside the window lessened considerably.
The incandescent light stabilized and no longer flickered.
The eyes of the hundred-plus Rhine cats that had reflected the lightning also grew gentle, as if the horror just now had only been a joke.
“Hey, hey.”
Qin Feng was the first to break the silence.
“Aren’t you scaring yourself a little too much? Caution is right, but being overly cautious really isn’t necessary.”
“If you get frightened with every step you take, then nothing can move forward.”
“In the end, this is just like those mysterious numbers from before. It’s all baseless delusion, even persecution paranoia.”
Jiang Ran smiled.
“I didn’t say it was definitely the case. I’m only making a guess.”
“The reason I have so many concerns—isn’t it because we can’t find answers to these two questions right in front of us?”
Sigh.
Problems like this, which could neither be proven nor disproven, were the most annoying. Jiang Ran was wavering back and forth, unable to make up his mind.
Cheng Mengxue looked from one of them to the other.
Then she carefully raised her hand.
“Um…”
Both of them looked at her. Cheng Mengxue pointed her index finger toward the small blackboard.
“Since Teacher Zhang Yang talked about worldline theory in class, and we also heard the term ‘worldline transition’ from his class…”
“Then why don’t we ask Teacher Zhang Yang about these two questions now?”
Jiang Ran blinked.
He looked back at the small blackboard.
Worldline transition…
His gaze focused on that term.
Indeed, this term was not something he had coined himself. It was something Teacher Zhang Yang had mentioned in general education class, something like Parallel Worlds and Worldline Theory.
He simply felt the term described his own situation very aptly, so when he had explained the issue to Cheng Mengxue, he had used it directly.
Teacher Zhang Yang was quite famous at the university.
It was not because he himself was especially outstanding, but because his teacher’s name was truly renowned. His teacher could be said to be one of the top veteran academicians in the Longguo Academy of Sciences in both seniority and ability.
As that veteran academician’s final disciple, after Teacher Zhang Yang graduated with his PhD, he returned to his alma mater, Donghai University, to take up a post. This year, he had just been promoted to graduate supervisor.
Looking at it that way, Teacher Zhang Yang could be considered someone who had come into contact with the very top of the physics world. He should know many cutting-edge theories that had yet to be made public.
Cheng Mengxue was right.
Since they had no clues at the moment, they might as well consult Teacher Zhang Yang, who was more professional than them, broader in experience, and deeper in knowledge.
“Xiao Xue has a point.”
Jiang Ran stood up.
“The problem we’ve encountered now just so happens to coincide with Teacher Zhang Yang’s research direction.”
“He talked about the knowledge point of ‘worldline transition’ in class. Although it was only a theoretical hypothesis, since we can’t find an answer, we might as well go hear his opinion. Perhaps there really will be some unexpected gain.”
“Of course, confidentiality is still necessary. We can’t mention the spacetime text messages, the positron cannon, or the experiments we’ve conducted. We’ll only ask hypothetical questions based on the class material.”
Qin Feng also agreed.
“Teacher Zhang Yang’s academic level is very high, and he studied under an academician from the Longguo Academy of Sciences. Maybe he really does have some profound insight.”
“Then it’s settled.”
Jiang Ran opened his phone and glanced at the class schedule.
“Although there’s no general education class with Teacher Zhang Yang tomorrow, he has a specialized course at the School of Physics. We’ll go ask him for advice when his class ends.”
…
The next day.
The three of them arrived early at the teaching building of the School of Physics and waited.
After Teacher Zhang Yang’s specialized course ended and the students left the classroom in twos and threes, the three of them went to the lectern and explained their purpose to Teacher Zhang Yang.
“Oh~ hehehe.”
Teacher Zhang Yang smiled as he unscrewed his thermos.
“I’m truly glad you came to see me. I’ve always thought the students in general education courses only came to coast for credits, and that not many listened seriously… There are even many students who treat my class like science fiction.”
“I didn’t expect there really would be students who listened and thought carefully about it. Wonderful, wonderful. Seeing the three of you truly gratifies me as your teacher. Go on, what do you want to ask? I don’t have class next period, so let’s have a proper chat here.”
Sure enough, as Qin Feng had said, Teacher Zhang Yang was a very nice person.
Cheng Mengxue was the first to raise her hand.
“Teacher Zhang, we’re very interested in the concept of ‘worldline transition’ you mentioned before. At the same time, there are some questions we don’t quite understand.”
“Oh? What don’t you understand?”
“It’s about the process of transition—the things that happen at the instant a worldline changes… We don’t quite understand it.”
Cheng Mengxue proceeded step by step and did not head straight for the main point from the beginning.
“Oh, oh. That is indeed a little complicated.”
Zhang Yang took a sip of tea and screwed the lid back onto his thermos.
“After all, what I taught you was a general education course, not a specialized one, so I didn’t explain it too thoroughly. Since you’re so interested, I’ll explain it to you again.”
He picked up a piece of chalk and drew a straight line on the blackboard. Then, at the end of the line, he split it into a fork, extending two parallel lines, one above and one below.
“To make it easier to understand, I’ll use my own life as an example.”
Teacher Zhang Yang pointed at the straight line in front.
“This straight line represents my life from birth to the age of eighteen. When I was eighteen, I failed the college entrance examination for the first time. At that moment, I faced two choices in life.”
“The first choice was to repeat a year of senior high school, then continue taking the college entrance exam… In my second year, I successfully got into Donghai University, then went on to pursue a PhD at the Longguo Academy of Sciences, then returned to my alma mater to teach, becoming your teacher.”
As he spoke, his finger slid across the fork in the straight line and moved onto the upper branch.
“This is the life I chose back then, which is also my current life. This worldline can be called Worldline A.”
Jiang Ran and the other two nodded.
This concept was not difficult to understand, especially since they had already discussed it countless times in private.
“However, when I failed the college entrance exam at eighteen, there was still a second choice in life.”
Teacher Zhang Yang moved his finger back to the fork in the straight line.
“I might also have chosen not to repeat the year and instead gone straight into society, or gone south to work.”
“Who knows? Maybe I would have seized the internet opportunities of those years and become the CEO of a listed company, an internet tycoon, a financial crocodile, or something like that.”
Cheng Mengxue was amused by Zhang Yang’s humor and laughed.
But anything was possible. Who could predict what the path not taken back then would have been like? What kind of life it would have led to?
This time, Teacher Zhang Yang’s finger did not move upward, but went toward the lower parallel line.
“Then, this worldline that Teacher Zhang did not choose—that is, the worldline in which I did not become your teacher, but instead became the CEO of a listed company—can be called Worldline B… You can understand this, right?”
The three of them nodded again.
Having experienced several worldline changes, they naturally could understand how different choices would branch into different worldlines.
“However.”
Teacher Zhang Yang’s tone shifted.
“These two worldlines cannot exist simultaneously.”
“Or rather, any two worldlines cannot exist simultaneously. Our world can only operate fixedly on a single worldline.”
His tone grew heavier.
“It’s just like the hypothetical experiment of Schrödinger’s cat. The cat in the box is either dead or alive. It is absolutely impossible for it to be ‘both dead and alive,’ or to be in some laughable ‘superposition of dead and alive.’”
…
Schrödinger’s cat.
It was a widely known thought experiment.
In the 1930s, the Copenhagen school led by Niels Bohr proposed the “quantum superposition state,” meaning that a quantum could be in multiple positions or multiple states at the same time.
Einstein and Schrödinger, however, believed this view to be absurd.
Einstein once wrote to Schrödinger and pointed out that for an unstable barrel of gunpowder, its state containing a superposition of exploded and unexploded was absurd.
Schrödinger thought the same.
To further elaborate on this absurdity, he proposed the famous thought experiment “Schrödinger’s Cat”—
A cat, a bottle of poison, and a radioactive source are sealed inside a box.
Whether the poison is released—meaning the cat’s life or death—depends on the state of the radioactive atom.
According to the Copenhagen interpretation of quantum mechanics, then, before the box is opened and artificially observed, the cat is in a superposition of life and death.
This was clearly ridiculous.
Even if the box was not opened, the cat inside could only be dead or alive. It could not be both dead and alive.
Just as Teacher Zhang Yang had said just now, he could not choose both to repeat the year and not to repeat the year at the same time, nor could he set foot on two worldlines at once.
But.
An even more ridiculous thing came afterward.
Schrödinger’s “Schrödinger’s Cat” experiment was originally intended as criticism, even mockery, of the Copenhagen school.
But in the end…
Because this experiment was easy to understand and spread widely, this seemingly self-contradictory experiment has now become part of the basic picture of contemporary quantum mechanics.
Who knew whether Schrödinger himself, if he saw this situation today, would feel speechless and helpless?
“Now, next comes the key point.”
Teacher Zhang Yang tapped the blackboard.
“Since different worldlines cannot exist simultaneously, if we, who are currently on Worldline A, want to jump over to Worldline B, we must employ some unconventional method.”
He smiled faintly and looked at the three of them from side to side.
“Now, the three of you, try to imagine—”
“What kind of action, exactly, would trigger a worldline change?”
“What would cause our world to jump from Worldline A… to Worldline B?”