Why have so many physicists shrugged off the paradoxes of quantum mechanics? • Hacker News Board

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

#61

Post by ttctciyf » Fri, Apr 19, 2019, 7:28 PM UTC

btilly wrote: post #56

ttctciyf wrote: post #31

Earlier quoted context omitted.

Many Worlds still owes us an explanation of the apparently huge difference between this, the actual, world and all the other apparently not quite so actual ones, does it not? The two most promising ideas (IMO) are the idea that the "wave function collapse" is a non-physical event describing a change in our knowledge, the quantum informatics approach as per Philip Ball's recent RI lecture,[1] and the "Relational" inte…

Many Worlds still owes us an explanation of the apparently huge difference between this, the actual, world and all the other apparently not quite so actual ones, does it not? No. For a start, there is no evidence that the ones you are calling "not quite so actual" are any less actual than the one we share an experience of. Continuing on, the interpretation does not attempt to explain the phenomena of perceived consci…

> For a start, there is no evidence that the ones you are calling "not quite so actual" are any less actual than the one we share an experience of.

Well, there is evidence of the one I'm calling "actual" - if it's evidence you want, there's no evidence at all of the "not so actual" ones - citing the MW interpretation as evidence of these is purely circular.

Regards not explaining perceived consciousness.. If MW is shunting off questions of actuality into something to be resolved by a theory of consciousness isn't it leaving behind centuries of consensus belief in the objective observer-independent existence of a physical world ontologically prior to consciousness?

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

#62

Post by gus_massa » Fri, Apr 19, 2019, 7:30 PM UTC

combatentropy wrote: post #58

It seems to me that the resolution of the quantum mysteries might come from three sources: (1) the Holographic Principle, (2) Dark Matter, and (3) the Planck Length. 1. The Holographic Principle. The universe looks three dimensional but fundamentally it is different. 3-D space is a projection from some 2-D circuit board. If I believe that, then I have no problem hearing about (a) hidden variables or (b) spooky action…

2) As far as I know, Dark Matter is totally unrelated to the quantum mysteries (uncertainty principle, measurement problem, ...)

3) In elementary particles, the magnetic moment is twice the expected value of a fake classical particle of the same mass and charge (for a complete accurate explanation see https://en.wikipedia.org/wiki/G-factor_(physics) ) For elementary particles the number is 2. For non elementary particles, it can be any number.

For electrons/muons/quarks the number is almost 2, and the difference is caused because the elementary particle has a cloud of virtual particles around. We can calculate this correction quite well. So there is a high chance that electrons/muons/quarks are actually elementary particles.

Anyway, I don't understand how the subdivision of the current elementary particles is related to the quantum mysteries. You get the same mysteries with electrons (that are probably elementary) and with protons (that are definitively not elementary).

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

#63

Post by nikofeyn » Fri, Apr 19, 2019, 7:39 PM UTC

dtech wrote: post #48

nikofeyn wrote: post #23

Earlier quoted context omitted.

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.

A model with a paradox is usually considered a flawed model, as it a logical contradiction, and from a logical contradiction anything can be proven. "Proof by contradiction" is a proof that the opposite is true, and is constructed so that if the thing you try to disprove would be true, you could create a paradox/contradiction.

> A model with a paradox is usually considered a flawed model

that is the critique at hand, is it not? my understanding of the paradoxes in quantum mechanics stem from things, like measurement, being unspecified or at least being specified or interpreted without consensus.

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

#64

Post by david927 » Fri, Apr 19, 2019, 7:52 PM UTC

Sylos wrote: post #35

gus_massa wrote: post #2

> 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…

> This is a common error. Macroscopic "everyday" objects don't have a definite position and momentum. Macroscopic objects are quantum objects. But when the mass is big enough, the position and momentum can be defined simultaneously with an error that is so small that you can just ignore the uncertainty and approximate them as classical objects. To put this into simpler terms: Whenever we measure something, we need to…

That's a nice explanation but doesn't it give the impression that if we could find a better way to do that experiment, we could find a way around the problem, when instead it's a fundamental limit on what we can know about a quantum system?

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

#65

Post by atq2119 » Fri, Apr 19, 2019, 11:34 PM UTC

philipov wrote: post #43

atq2119 wrote: post #36

Earlier quoted context omitted.

To be more precise, we are in all of them, but our consciousness only perceives one of them. So the real problem isn't in quantum mechanics, it's in what the hell consciousness is and why it works the way it does. However, note that you can have observations performed by a computer which e.g. counts events, and the counter will exist in all "worlds" (branches of the universal wave function, really), while each incarn…

Why is it necessary for consiousness to be any different from that computer counter? It seems to me that the paradoxical idea is not quantum mechanics, but rather conciousness.

I actually agree with you. If you can accept that consciousness is basically a computer, then there isn't really anything mysterious going on. I probably could have phrased that better.

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

#66

Post by gus_massa » Sat, Apr 20, 2019, 3:13 AM UTC

david927 wrote: post #64

Sylos wrote: post #35

Earlier quoted context omitted.

> This is a common error. Macroscopic "everyday" objects don't have a definite position and momentum. Macroscopic objects are quantum objects. But when the mass is big enough, the position and momentum can be defined simultaneously with an error that is so small that you can just ignore the uncertainty and approximate them as classical objects. To put this into simpler terms: Whenever we measure something, we need to…

That's a nice explanation but doesn't it give the impression that if we could find a better way to do that experiment, we could find a way around the problem, when instead it's a fundamental limit on what we can know about a quantum system?

I agree with both. This explanation is easier to understand, but it makes it look like a technological problem that can be solved, instead of a fundamental property of the universe.

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

#67

Post by q_revert » Sat, Apr 20, 2019, 9:03 AM UTC

because it's really hard, and they need to publish :)

-- phd in physics

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

#68

Post by atomack » Sat, Apr 20, 2019, 9:10 AM UTC

gus_massa wrote: post #66

david927 wrote: post #64

Earlier quoted context omitted.

That's a nice explanation but doesn't it give the impression that if we could find a better way to do that experiment, we could find a way around the problem, when instead it's a fundamental limit on what we can know about a quantum system?

I agree with both. This explanation is easier to understand, but it makes it look like a technological problem that can be solved, instead of a fundamental property of the universe.

I think david927's intuition is more correct here. The uncertainty in the position and momentum is intrinsic to quantum mechanics - it's built into the 'wave function'.

The suggestion that if one pushes away something by throwing something else builds on a purely classical intuition and wouldn't require quantum mechanics to explain if this was all we observed. The uncertainty in quantum mechanics is fundamental (to quantum mechanics) and emerges through a different, as yet unknown, mechanism.

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

#69

Post by lou1306 » Sat, Apr 20, 2019, 9:15 AM UTC

throwawaymath wrote: post #53

ttlei wrote: post #51

Correct me if I am wrong, the "paradoxes" described here are due to our lack of understanding of the theory right and not because the theory is inconsistent.

In what circumstance does that not describe a paradox?

For instance, Russel's paradox arises from an inconsistent naive set theory.

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

#70

Post by atomack » Sat, Apr 20, 2019, 9:22 AM UTC

It's a bit ungenerous to physicists to suggest they've simply shrugged off the paradoxes of quantum mechanics. The first couple of paragraphs outline reasons why quantum mechanics has gained so much traction. The various attempts to understand its more difficult results have turned out to be notoriously difficult to substantiate or disprove experimentally.

I don't actually dispute the socialogical forces the author describes as they apply to physics research but I don't think apparent lack of progress is due to lack of concern amongst the physics community.