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Reimagining of Schrodinger's Cat Breaks Quantum Mechanics -- and Stumps Physicists (nature.com)
In a multi-'cat' experiment, the textbook interpretation of quantum theory seems to lead to contradictory pictures of reality, physicists claim. New submitter Lanodonal shares a report: In the world's most famous thought experiment, physicist Erwin Schrodinger described how a cat in a box could be in an uncertain predicament. The peculiar rules of quantum theory meant that it could be both dead and alive, until the box was opened and the cat's state measured. Now, two physicists have devised a modern version of the paradox by replacing the cat with a physicist doing experiments -- with shocking implications.
Quantum theory has a long history of thought experiments, and in most cases these are used to point to weaknesses in various interpretations of quantum mechanics. But the latest version, which involves multiple players, is unusual: it shows that if the standard interpretation of quantum mechanics is correct, then different experimenters can reach opposite conclusions about what the physicist in the box has measured. This means that quantum theory contradicts itself.
The conceptual experiment has been debated with gusto in physics circles for more than two years -- and has left most researchers stumped, even in a field accustomed to weird concepts. "I think this is a whole new level of weirdness," says Matthew Leifer, a theoretical physicist at Chapman University in Orange, California. The authors, Daniela Frauchiger and Renato Renner of the Swiss Federal Institute of Technology (ETH) in Zurich, posted their first version of the argument online in April 2016. The final paper [PDF] appears in Nature Communications on 18 September.
Quantum theory has a long history of thought experiments, and in most cases these are used to point to weaknesses in various interpretations of quantum mechanics. But the latest version, which involves multiple players, is unusual: it shows that if the standard interpretation of quantum mechanics is correct, then different experimenters can reach opposite conclusions about what the physicist in the box has measured. This means that quantum theory contradicts itself.
The conceptual experiment has been debated with gusto in physics circles for more than two years -- and has left most researchers stumped, even in a field accustomed to weird concepts. "I think this is a whole new level of weirdness," says Matthew Leifer, a theoretical physicist at Chapman University in Orange, California. The authors, Daniela Frauchiger and Renato Renner of the Swiss Federal Institute of Technology (ETH) in Zurich, posted their first version of the argument online in April 2016. The final paper [PDF] appears in Nature Communications on 18 September.
I don’t think it’s possible to KNOW precisely at any given moment whether quantum mechanics is broken, and to what degree it IS broken if indeed it is. That’s kind of the point of quantum mechanics.
OR...
If a mechanic breaks your quantum, he should have to fix it, theoretically.
I cant decide which joke to go with, so I've decided on a quantum superposition of both:
If don’t mechanic it’s your to he preciesly have any fix...
Hehehehe... quantum humor... simultaneously both really funny, and not funny at all, but you won’t know WHICH it is unitl you read the joke and collapse the wave-function.
Our reign has gone on long enough. Indeed. Summon the meteors.
Yeah, this isn’t so much a quantum mechanics problem as an illustration of how journalists, bloggers, and the like can fall into the trap of thinking understanding some extremely simplified model of something means they also understand the complex underlying system.*
In the end it’s a nonsensical self-contradiction by definition; sort of like when you were an 8-year-old kid and became fascinated with the conundrum “Can an omnipotent God make a stone too big for him to lift?”
* Like putting too much air into a balloon!
#DeleteChrome
No, the whole point was to point out the absurdity of the Copenhagen interpretation. Unfortunately, most people tend to miss this part and think that SchrÃdinger espoused the point of view that he was actually arguing against.
And the Copenhagen interpretation is the new "Bohr atom model" - almost no one believes it this century, but it's still widely discussed and often taught in intro-level classes, out of simple tradition.
Anyhow, measurement devices collapse the wave state, removing this sort of uncertainty at the point of measurement.* It was never a very good thought experiment in the first place. The fact that you can't scale up quantum uncertainty to the macro scale in any straightforward way is the answer to SchrÃdinger's question.
* That's usually explained very early on even in describing "quantum weirdness" in lay terms. The two slit experiment stops giving a diffraction pattern as soon as you measure which slit the photons/electrons/whatever go through.
Socialism: a lie told by totalitarians and believed by fools.
Schrödinger's point about the cat thought experiment is that that cat is NOT in two separate states at the same time. That was his expressing his aggravation about the contradiction of the results of his work and reality.
The question remains, "How does potential get resolved?"
I think they're trying to talk about boundaries across which things have NOT been interacting (in a quantum-state destructive way) yet.
No matter how complex the thing inside a boundary is, you could in principle (t least in a thought experiment) have the whole thing not entangled in any way with the observer and their entangled environment. So can that complex but isolated thing be in a quantum state/superposition, FROM THE PERSPECTIVE of the outside observer?
I suspect that was the idea of the box concept.
Where are we going and why are we in a handbasket?
The whole point of Schrodinger's cat experiment [phys.org] was to show that trying to apply certain quantum physics theories to reality resulted in absurd results.
No, it is more subtle than that. It was designed to show that one interpretation of the results of QM was wrong by showing that it leads to an absurd explanation for every-day scale objects like cats. Nobody ever believed that the cat was in some weird superposition: that was indeed the entire point. The interpretation of QM, called the Copenhagen interpretation, was clearly wrong which is why nobody believes it today. However, everyone believes in quantum mechanics itself and that it works when describing reality (it's the second most precisely tested scientific theory that has ever existed). The problem is trying to get brains that are used to a world that works in the large-scale limit of QM to really grasp the rather different underlying reality.
Do you not know how to read? Read the actual link you linked to; there is basically one person who claims this orthodox interpretation is "now widely felt to be unacceptable." Given how wrong Einstein turned out to be about quantum mechanics, it wouldn't be surprising at all if this one Nobel laureate also turned out to be wrong.
The farthest you can go (and not be laughably wrong) is that there is broad consensus that there is something to be fixed in Copenhagen interpretation—but there is no other interpretation that is more broadly accepted than Copenhagen interpretation.
Anyhow, measurement devices collapse the wave state, removing this sort of uncertainty at the point of measurement
Yeees. And it only requires probability wave states that "collapse" at literally infinite speeds... nothing can possibly go wrong with this final, slayer-of-all-others, supreme, holy "interpretation", no-seree-bob, nothing, I tell ya!
Many worlds makes quick work of this whole thing. Referencing original explanation, 3 subsets of multiverse: AA,AB & B. In subsets starting with A, Alice in her box sets up spin sideways, in B, spin down. In AA, Bob measures spin up, in AB & B, spin down.
The contradiction is supposed to be in AB Alice is in superposition to Bob, but not to herself. But in many worlds, everyone was always in AB, but they couldn't know that until diverging from copies of themselves in parallel worlds, which they only do when information about choices occurs. It's all beautifully consistent.
-The art of programming is the pursuit of absolute simplicity.
Well, the original Copenhagen thing referred to an "observer" and everybody jumped to the absurd conclusion that it must be a conscious human observer. As opposed to a cat, or indeed a Geiger counter.
These days, only popular science-mangling magazines (and some stupid schoolbook authors) still perpetrate that both-alive-and-dead-superposition nonsense.