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Why have so many physicists shrugged off the paradoxes of quantum mechanics?

thenewatlantis.com

21–30 of 132 posts

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#21
post #7

> Bohr postulated a distinction between the quantum world and the world of everyday objects. A “classical” object is an object of everyday experience. It has, for example, a definite position and momentum, whether observed or not. A “quantum” object, such as an electron, has a different status; it’s an abstraction. Some properties, such as electrical charge, belong to the electron abstraction intrinsically, but other…

I thought the current fad was to use holography to explain it. The problem is that to measure something in quantum mechanics requires separating the world into two systems. To make exact measurements, the observing system has to be infinitely large to avoid quantum fluctuation, and the experiment has to be repeated infinitely often because it is probabilistic. To deal with the infinite size, particle physicists push…

A route other than "dividing the world into two categories," has been available since the early days of quantum mechanics, if you believe in many worlds you don't have that problem. It is important to recognize that we are not talking about physics here, we are talking about philosophy.

If anything, the greatest shock of quantum mechanics is how it shows that "questions we naturally want to ask about the natural world" and "totally unresolvable philosophical disputes" are not completely disjoint.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#22
post #14

Earlier quoted context omitted.

you could say that about any paradox. it other words, it isn't a helpful position because it doesn't give any insight. why even have the word paradox? plus, our intuition is just as much a part of reality as your "reality".

Your definition of reality here is unrelated to the OP's point. Quantum mechanics will work the way it does regardless of what your intuition on how it should work thinks. Also the emergence of an apparently paradox is a great heuristic that raises the question of whether our intuition and understanding is wrong or correct.

It's not a matter of intuition, it's a matter of incompleteness or inconsistence in the theory. There is no theoretrically testable explanation of what happens when states transition in quantum mechanics.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#23
post #18

Earlier quoted context omitted.

you could say that about any paradox. it other words, it isn't a helpful position because it doesn't give any insight. why even have the word paradox? plus, our intuition is just as much a part of reality as your "reality".

A paradox is essentially a logical contradiction. As far as we know such contradictions don't occur in nature. Paradoxes indicate that there is a flaw in either our theory or our understanding of our theory.

right. but saying there aren't paradoxes in quantum mechanics isn't helpful and is probably just wrong. quantum mechanics isn't a physical thing and isn't reality. it is a model. of course it can have paradoxes, and does.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#24

They aren't paradoxes of quantum mechanics. They are a paradox between how we intuitively expect the world to work and reality. Our intuition is wrong.

you could say that about any paradox. it other words, it isn't a helpful position because it doesn't give any insight. why even have the word paradox? plus, our intuition is just as much a part of reality as your "reality".

Bingo. Sufficiently unintuitive reality is indistinguishable from paradox.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#25
post #15

Earlier quoted context omitted.

No, there is not. The Everett aka many-worlds interpretation demonstrates that you can explain the observed effects of measurement without invoking "collapse" of the wave function, and without reference to anything outside of QM.

To further build on what you're saying, by bringing in the concept of a measure-er we have already entered the domain of philosophy, because the special class "measure-er" belongs to the Copenhagen interpretation and the interpretation of quantum mechanics is a philosophical issue by virtue of the fact that it will never be decided experimentally.

Philosophical issues mean that the theory is wrong and new physics will come from their resolution, and thus philosophical issues can be decided experimentally.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#26
post #12

Earlier quoted context omitted.

Yes there are. Even without invoking any philosophical issues, quantum mechanics admits it's not self-contained. It takes measurement - the act of an outsider interacting with a system, which collapses the wavefunction, as a postulate. Measurement is not described by quantum mechanics.

Yes it is. Measurement is entanglement between the observed system and the observing system. Wave function collapse is an illusion caused by the two systems no longer being separable. They have entered a mixed state. It looks like information is lost in the observed system only because you are ignoring the observer.

You've just replaced the problem of collapse with the problem of which universe we transition to. We are only in one.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#28

> Bohr postulated a distinction between the quantum world and the world of everyday objects. A “classical” object is an object of everyday experience. It has, for example, a definite position and momentum, whether observed or not. A “quantum” object, such as an electron, has a different status; it’s an abstraction. Some properties, such as electrical charge, belong to the electron abstraction intrinsically, but other…

Well put.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#29
post #7

Earlier quoted context omitted.

I thought the current fad was to use holography to explain it. The problem is that to measure something in quantum mechanics requires separating the world into two systems. To make exact measurements, the observing system has to be infinitely large to avoid quantum fluctuation, and the experiment has to be repeated infinitely often because it is probabilistic. To deal with the infinite size, particle physicists push…

A route other than "dividing the world into two categories," has been available since the early days of quantum mechanics, if you believe in many worlds you don't have that problem. It is important to recognize that we are not talking about physics here, we are talking about philosophy. If anything, the greatest shock of quantum mechanics is how it shows that "questions we naturally want to ask about the natural worl…

And that is exactly why it isn't a paradox in quantum mechanics. Quantum mechanics is consistent for the domain of questions it was designed to ask: particle scattering experiments. It's when people push it into philosophy or other unintended domains that they run into problems.

Re: Why have so many physicists shrugged off the paradoxes of quantum mechanics?

#30

Earlier quoted context omitted.

can we measure that imprecision of momentum/position relation even though small?

No. It would take far more digits of accuracy than we can measure. For example, here's an object of 1 kg mass. The product of the uncertainty of its position and momentum is h-bar / 2, or h / 4 pi, which is about 5e-35 kg m^2/s. We're going to measure the position to one wavelength of visible light (say, 500 nm wavelength, so 5e-7 m). That means that we need to be able to measure the momentum to an accuracy of 1e-28…

Good reply.
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