Prodigy’s Playground

Chapter 22 Zhang Yang

After the lightning and thunder, the rain outside the window eased up a lot.

The fluorescent light’s brightness stabilized and stopped flickering.

The hundreds of Rhine Cat eyes reflecting the lightning also softened, as if the fright from just now had been nothing but a joke.

“Hey, hey.”

Qin Feng broke the silence first:

“Aren’t you kind of scaring yourself at this point? Being cautious is right, but there’s really no need to be overly cautious.”

“If you take one step and then fear the next step, you won’t be able to move anything forward.”

“At the end of the day, this is just like those mystery digits from before—baseless conjecture, even persecution paranoia.”

Jiang Ran smiled.

“I didn’t say it had to be that way. I’m just guessing.”“And the only reason I have so many worries is because we can’t find answers to these two questions right in front of us, isn’t it?”

Sigh.

These problems that you couldn’t prove and also couldn’t falsify were the most annoying. Jiang Ran kept seesawing back and forth, unable to decide.

Cheng Mengxue looked between the two of them.

She cautiously raised her hand.

“Um…”

When both of them looked over, Cheng Mengxue pointed at the small blackboard with her index finger.

“Since Professor Zhang Yang talked about Worldline Theory in class, and we also heard the term Worldline Transition from his class…”

“[Then why don’t we go ask Professor Zhang Yang about these two questions?]”

Jiang Ran blinked.

He looked back at the small blackboard.

Worldline Transition…

His gaze fixed on the term.

It was true—this term wasn’t something he had invented. Professor Zhang Yang had brought it up in a general-education class, something like Parallel Worlds and Worldline Theory.

It was just that Jiang Ran had felt the term fit his situation perfectly, so when he explained the problem to Cheng Mengxue, he’d directly borrowed it.

Professor Zhang Yang was well-known at the university.

Not because he personally was so outstanding, but because his mentor’s name was thunderous—an old academician whose seniority and strength in the Dragon Country Academy of Sciences could be counted among the very top.

As that old academician’s last disciple, Professor Zhang Yang had returned to his alma mater, Donghai University, after completing his doctorate. This year, they had just been promoted to a graduate advisor.

Put that way, Professor Zhang Yang counted as someone who’d been in contact with the very top tier of the physics world. They should know a lot of cutting-edge theory that hadn’t been made public yet.

Cheng Mengxue was right.

Since they had no leads at all, it was better to consult someone more professional than them, with broader experience and deeper learning—Professor Zhang Yang.

“Xiaoxue has a point.”

Jiang Ran stood up.

“The problem we’re facing now just happens to align with Professor Zhang Yang’s research direction.”

“They even talked about the knowledge point [Worldline Transition] in class. Even if it was only a theoretical hypothesis, if we can’t find an answer ourselves, we might as well hear their view. Maybe we’ll actually gain something unexpected.”

“Of course, secrecy is still mandatory. The time-traveling text messages, the Positron Cannon, and everything about our experiments—we can’t say any of it. We’ll only ask hypotheticals based on classroom knowledge.”

Qin Feng agreed as well.

“Professor Zhang Yang’s academic level is high, and they studied under an academician from the Dragon Country Academy of Sciences. Maybe they really do have some insightful view.”

“Then it’s settled.”

Jiang Ran opened his phone and glanced at the timetable.

“Even though we don’t have Professor Zhang Yang’s general-education class tomorrow, they have a specialized course in the School of Physics. We’ll catch them when they get out of class and ask.”

…

The next day.

The three of them arrived early and waited outside the teaching building for the School of Physics.

When Professor Zhang Yang’s specialized class ended and students filed out in twos and threes, the three of them went up to the lectern and explained why they were there.

“Oh~ hehehe.”

Professor Zhang Yang smiled as they unscrewed a thermos cup.

“I’m really happy you came to me. I’ve always thought students in general-education classes are just here to pad credits—there aren’t many who listen seriously… There are even plenty of students who treat my class like they’re listening to science fiction.”

“I didn’t expect there’d actually be students who took it in and seriously thought about it. Very good, very good. Seeing the three of you really makes me feel gratified. Go on—what do you want to ask? I don’t have a class next period. I’ll stay here and have a proper chat with you.”

Just like Qin Feng had said, Professor Zhang Yang was really nice.

Cheng Mengxue raised her hand first.

“Professor Zhang, we’re very interested in the concept of [Worldline Transition] you talked about before. But there are also some questions we can’t figure out.”

“Oh? What can’t you figure out?”

“It’s about the transition process—the things that happen in the instant of the worldline’s change… We can’t quite understand it.”

Cheng Mengxue took it step by step, not rushing straight to the main point at the start.

“Oh, oh. That is a bit complicated.”

Professor Zhang Yang took a sip of tea and screwed the thermos lid back on.

“After all, what I taught you was a general-education class, not a specialized course, so I didn’t go into it too thoroughly. Since you’re so interested, I’ll explain it to you again.”

They picked up a piece of chalk and drew a straight line on the blackboard. Then, at the end of the line, they split it into a fork—one branch up, one branch down—extending into two parallel lines.

“To make it easier to understand, I’ll use my own real life as an example.”

Professor Zhang Yang pointed at the first straight line.

“This straight line represents my life from birth to age eighteen. When I was eighteen, I failed the college entrance exam for the first time. At that point, I faced two life choices.”

“The first choice was to repeat a year and redo senior year of high school, then take the exam again… The second year I got into Donghai University successfully, then did my doctorate at the Dragon Country Academy of Sciences, then returned to my alma mater to teach—becoming your professor.”

As they spoke, their finger slid over the fork in the line and moved along the upper branch.

“This is the life I chose back then—my current life. So this worldline, we can call it Worldline A.”

The three of them nodded.

The concept wasn’t hard to understand—especially since they’d already discussed it privately countless times.

“But when I failed the exam at eighteen, there was also a second choice.”

Professor Zhang Yang’s finger returned to the fork.

“I could also have chosen not to repeat a year. I might have entered society directly, or gone south to work.”

“Maybe I would’ve caught the internet opportunities of those years and become the boss of a listed company, some internet giant, some financial predator, something like that.”

Cheng Mengxue laughed at Professor Zhang Yang’s humor.

But anything was possible. Who could predict what the road you didn’t choose would have become—what kind of life it would have led to?

This time, Professor Zhang Yang’s finger didn’t go upward. It moved toward the lower parallel line.

“Then this worldline—the one Teacher Zhang didn’t choose, the one where I didn’t become your professor but instead became the boss of a listed company—we call that Worldline B… You understand that, right?”

The three of them nodded again.

Having already experienced multiple worldline changes, they naturally understood that different choices could branch into different worldlines.

“But.”

Professor Zhang Yang’s tone shifted.

“[These two worldlines cannot exist at the same time.]”

“[Or rather, any two worldlines cannot exist at the same time. Our world can only run fixed on one worldline.]”

They emphasized their words.

“Just like the hypothetical experiment Schrödinger’s Cat. The cat in the box is either dead or alive. There absolutely cannot be something ridiculous like ‘it’s dead and alive at the same time,’ or some ‘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 “quantum superposition”—meaning a quantum could be [simultaneously] in multiple positions or multiple states.

Einstein and Schrödinger, however, believed that viewpoint was absurd.

Einstein once wrote to Schrödinger and pointed out that the state of an unstable gunpowder barrel containing a superposition of “exploded” and “not exploded” was ridiculous.

Schrödinger thought the same.

To further illustrate that absurdity, he proposed the famous thought experiment Schrödinger’s Cat—

A cat, a bottle of poison, and a radiation source were sealed inside a box.

Whether the poison was released—meaning whether the cat lived or died—depended on the state of a radioactive atom.

Then, according to the Copenhagen interpretation of quantum mechanics, before the box was opened and a human observed it, the cat existed in a superposition of life and death.

That was obviously laughable.

Even if the box wasn’t opened, the cat inside could only be dead or alive. It couldn’t be dead and alive at the same time.

Just as Professor Zhang Yang had said: they couldn’t have simultaneously chosen to repeat a year and not repeat a year. They couldn’t have simultaneously stood on two worldlines.

But—

Something even more laughable came after.

Schrödinger’s Schrödinger’s Cat experiment had originally been meant as criticism, even mockery, of the Copenhagen school.

Yet…

Because the experiment was easy to understand and spread widely, today this seemingly self-contradictory experiment had instead become part of the basic imagery of modern quantum mechanics.

Who knew whether Schrödinger himself, seeing how things turned out today, would feel speechless and helpless.

“Now then, the key point is next.”

Professor Zhang Yang tapped the blackboard.

“Since different worldlines cannot exist at the same time, then for us—who are currently in Worldline A—to jump to Worldline B, we must adopt some unconventional means.”

They smiled slightly and looked from left to right at the three of them.

“Now, you three imagine this—”

“What kind of action would trigger a worldline change?”

“What would make our world jump from Worldline A… to Worldline B?”