1900: A physics genius wandering around Europe

Chapter 595: Light-year thought experiment! Action at a distance! The dispute between locality and non-locality! The whole audience was shocked!
The shock that path integral brings to everyone is no less than the principle of complementarity.

People with good mathematical knowledge, such as Born, Dirac and others, have already felt the uniqueness of this theory.

Compared with wave mechanics and matrix mechanics, it can describe the state changes of electrons more intuitively and is very consistent with human intuition.

The experts firmly believe that there is more to be explored regarding path integrals.

The 4th Bruce Conference will open up new research directions for physics!

The atmosphere of the free discussion became more lively.

Bohr, Heisenberg, Pauli and others all had smiles on their faces.

If nothing unexpected happens, this conference will completely establish the position of quantum mechanics in physics.

The connotation of Bruce's interpretation represents the most profound understanding of the world by quantum mechanics and is the most authoritative orthodox explanation!
It has withstood various doubts from great men such as Einstein, which is a test of the truth.

Even once Professor Bruce achieves a breakthrough in the field of quantized fields, quantum mechanics will usher in a second spring!

“It’s really a quantum heyday!”

Bohr couldn't help but sigh.

As a representative of the old quantum theory, he is qualified to say such things.

However, just as Bohr was excited and imagining the bright future of quantum mechanics.

Einstein stood up again.

And this time, he will launch his last attack!
He smiled and said:

"Bruce, your path integral theory is truly amazing."

"But I would like you to explain one thing again."

"If you can convince me again this time, I will never question this theory again."

Wow!
Everyone in the audience was shocked when they heard this!
Everyone looked at Einstein, with disbelief written all over their faces.

"My God!"

"Professor Einstein hasn't given up yet?"

"Did he discover some crucial problem?"

Everyone admires Einstein very much.

There are only a handful of people who can fight with Professor Bruce.

Although he had failed before, things like the light box experiment were very instructive.

For science, experiences of both failure and success are rare and valuable.

"And judging from Professor Einstein's momentum this time, it's extraordinary."

“I always feel like he’s going to make some big news.”

The enthusiasm of the spectators was instantly aroused.

Li Qiwei smiled slightly and said calmly:
"Einstein, come on."

"After today, I will let you embrace quantum mechanics!"

Wow!
The discussion is about to break out!
Einstein smiled mysteriously, feeling as if his evil plan had succeeded.

He said confidently:

"Bruce, I'm afraid you're going to suffer a Waterloo this time."

Then he walked to the front of the crowd and began to speak:
"What I am questioning this time is the existence of objectivity that is independent of the observer."

"My view remains that quantum mechanics is incomplete."

"I discovered a paradox last night when I was communicating with Professor Schrödinger."

Swish!
Many people looked at Schrödinger, which made the latter very confused.

Heisenberg raised the corners of his mouth, not worried.

"It's just a dying struggle."

At this point, Einstein continued:
“Let me propose a thought experiment, taking the uncertainty principle as an example.”

"In matrix mechanics, the position and momentum of a single electron satisfy the non-commutative property, which leads to the uncertainty principle."

“That is, it is impossible to measure both the position and momentum of a particle at the same time.”

"But for a pair of electrons, the sum of their relative distance and momenta is commutative."

"Thus, the distance and the sum of the momentum between the two electrons can be measured simultaneously at any given moment."

“I think everyone should have no doubt about this.”

Everyone nodded after hearing this.

Although they didn't understand what Professor Einstein wanted to say, they thought his conclusion was correct.

Heisenberg frowned slightly.

The uncertainty principle applies to the position and momentum of a single quantum.

But if the two quantum particles are regarded as a system, the sum of their relative distance and momentum no longer satisfies the uncertainty relationship.

This is generally difficult to know unless you have a deep study of matrix mechanics.

Heisenberg never dared to underestimate Einstein again.

"As expected, he was once as famous as Professor Bruce."

Einstein looked at the crowd, smiled gently, and then said:

"Okay, now let's start the thought experiment."

"Suppose there are two electrons, X and Y. After they come into contact and collide, they move in opposite directions."

"At this point, the momentum between the two electrons is conserved, and the relative distance between them is known."

"Assume that the relative distance between the two electrons is 1 light year."

"Now, if we can accurately measure the momentum of electron X, then we can know the momentum of electron Y based on the law of conservation of momentum."

"This shows that the momentum of electron Y is a [definite] physical quantity that [does not depend on any factors]."

"Similarly, if we can accurately measure the position of electron X, we can know the position of electron Y based on the relative distance."

"This shows that the momentum of electron Y is also a definite physical quantity."

At this time, Heisenberg couldn't help but question:

"Professor Einstein, I think you are overlooking a problem."

"Due to the uncertainty principle, we cannot precisely measure the position and momentum of a single quantum simultaneously."

"When you first measure the momentum of electron X, you perturb it, causing the position of electron X to change."

"When you measure the position of electron X a second time, it is no longer the same value as before."

"Therefore, the position of electron Y calculated based on the relative distance is also inaccurate."

Wow!
Heisenberg's question made everyone nod.

Obviously, Professor Einstein's thought experiment cannot prove that there is a problem with the uncertainty principle.

However, Bohr frowned slightly.

He looked at Einstein, who was smiling and calm, and always felt that things were not that simple.

"Why did Professor Einstein specifically mention the distance of 1 light year?"

“This distance is a bit too big.”

Everyone was talking in low voices.

Only Li Qiwei has seen through everything!
He knew what Einstein wanted to ask.

However, Lao Ai is destined to end in tragedy again this time.

At this time, Einstein smiled and replied:
"Professor Heisenberg's questioning just now is very reasonable."

"However, he overlooked a key factor!"

"That means the relative distance between electron X and electron Y is 1 light year."

"According to special relativity, the speed of any interaction cannot exceed the speed of light."

"And now, when we measure the momentum of electron X first, we know the momentum of electron Y."

"At this time, the position information of electron X has changed."

"But this change will not have any effect on electron Y, which is one light-year away."

"Because the speed of any interaction cannot exceed the speed of light."

"So, the position of electron Y actually has a definite value before measuring the position of electron X."

"In this way, the position and momentum of electron Y are actually definite."

"But the uncertainty principle denies its real existence."

"So I think quantum mechanics is incomplete."

quiet!
Deathly silence!

Everyone was stunned by Einstein's thought experiment!
"My God!"

"I feel like there is nothing wrong with Professor Einstein's experiment this time."

“It seems like there is indeed a problem with the uncertainty principle.”

“Is this the strength of the boss?”

"They keep fighting after repeated defeats, how terrifying!" A heated discussion suddenly broke out in the meeting hall.

Compared with the previous light box experiment, this "light-year experiment" is undoubtedly like a heavy hammer, hitting the vital point of quantum mechanics.

Because this experiment is related to the speed of light which cannot be exceeded.

If God appears, one of the two, saying that the speed of light cannot be exceeded and the uncertainty principle, is wrong.

Then the bigwigs present here will definitely support without hesitation that the speed of light cannot be surpassed.

Now, Einstein cleverly combined the two, creating a contradiction, and thus questioned the uncertainty principle.

What a genius idea!

Schrodinger's face was filled with shock.

The joke he made the night before was actually realized by Professor Einstein.

The other party really found the contradiction between quantum mechanics and relativity.

Moreover, the conclusion that the speed of light cannot be exceeded has long been a consensus in the academic community.

"Professor Einstein is absolutely underrated."

"His gifts and talents have not been fully utilized."

Schrödinger was full of admiration for Einstein.

To be able to come up with such a logical paradox in such a short time, he is definitely a genius among geniuses.

He looked at Professor Bruce and the others, thinking that quantum mechanics was in trouble now.

Sure enough, Heisenberg's face instantly turned the color of liver.

Just now he was dismissive of Einstein's questioning, thinking that the other party had made another common sense mistake.

I didn't expect to be slapped in the face in the blink of an eye.

Einstein had already deeply understood the uncertainty principle and set up the logical trap of 1 light year.

That the speed of light cannot be exceeded is one of the important conclusions of the special theory of relativity.

That is, there is no action at a distance in the world.

Now the uncertainty principle and the fact that the speed of light cannot be exceeded conflict directly confused Heisenberg.

Since the latter cannot be wrong, then the former can only be wrong.

"impossible!"

"Absolutely impossible!"

Heisenberg developed his brain to the extreme, trying to find loopholes in the light-year thought experiment.

Unfortunately, he can't.

This experiment was absolutely perfect.

Bohr still looked calm.

Just as he guessed, Einstein did indeed make use of the issue of light years.

Bohr personally firmly believed that the speed of light could not be exceeded.

So, the logic of this thought experiment is completely correct.

However, the uncertainty principle dictates that it is impossible for a particle to have both precise position and momentum at the same time.

If one is determined, the other will definitely change.

But how can this change be transmitted over a distance of 1 light year?

Bohr thought hard.

"Do we really have to transmit one light year?"

"No! No!"

"This is a thought experiment. If two electrons are 1 million light years apart, will it take 1 million years for the electrons to transmit their energy at the speed of light?"

"There must be something fishy about it."

Bohr couldn't figure it out.

He felt that Professor Einstein's question this time was too fatal.

It is very likely to overturn the foundations of quantum mechanics.

Subconsciously, he looked at Professor Bruce again.

Suddenly, Bohr calmed down.

Professor Bruce in front of him was still calm and composed, with deep eyes.

It seems that nothing in the world can defeat him.

Bohr felt that he could only learn the basics of this temperament and courage.

He did not ask the teacher for help immediately, but tried to solve the problem through his own thinking.

If the big guys have to take care of every problem, what are the little brothers for?

So, Bohr, Heisenberg, Pauli and others continued to ponder or discuss with each other.

Einstein was in high spirits. He felt that he had finally succeeded this time.

"There really is something wrong with quantum mechanics."

He continued:

"My thought experiment is essentially a local hypothesis."

"That is: quantum mechanics is only correct within a specific local area."

"For example, the uncertainty principle is certainly correct at scales much smaller than a light-year."

“Many experiments have proven its correctness.”

“I’m not denying it.”

"However, this correctness requires conditions, just as chemical reactions require various specific conditions."

"Professor Bruce believes that quantum mechanics is [non-local]."

"That is: quantum mechanics is true at every scale."

"Because only such a theory is a truly perfect theory."

"If a theory is local, its importance is greatly reduced."

Einstein raised the experiment to the level of theory, which shocked everyone.

The debate between locality and nonlocality may be the most core debate in quantum mechanics!
At present, Einstein's locality hypothesis still prevails.

At least no one could explain his thought experiment, and they couldn't find any problem at all.

Just when everyone thought that Professor Bruce would take action, an unexpected person spoke.

Gudsmith mustered up his courage and said:
"Professor Einstein, I think your thought experiment can be expanded."

“It doesn’t have to be the uncertainty principle that’s the example.”

Wow!
Everyone was shocked!
Many people think that this thought experiment is specifically aimed at the uncertainty principle.

From what Goudsmit said, are other conclusions of quantum mechanics also local?

"My God!"

“Is quantum mechanics going to suffer a Waterloo today?”

"This is really fun."

The bigwigs present all knew the young man named Goodsmith.

He is one of the discoverers of electron spin, which has great potential.

Ehrenfest looked at his students, feeling deeply moved.

"Young people are still good, they have quick minds."

In a meeting like today, he can only become a spectator.

However, his own students were able to stand up and fight alongside the big guys of the time to challenge Professor Bruce.

Pauli looked at Gudsmit with a fierce look in his eyes, and angrily said in his heart:

"It's like a tiger in plain land being bullied by a dog."

"He even dared to step on a rookie like Goodsmith."

"You really think you are a great ancient."

Einstein was overjoyed when he heard this.

He finally won over his teammates with his own strength.

And it wasn't just Schrödinger who supported him.

This fully demonstrates how amazing his thought experiment was this time, and even the neutrals began to lean towards him.

So he smiled and said:

"Go on, please, Gudsmith."

"Give your opinion."

(End of this chapter)