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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.
Is this just another way of saying "Number 7 will shock you!"
We replaced the cat with Folgers Crystals. Let’s see if anyone notices.
In the world's most famous thought experiment, physicist Erwin Schrodinger described how a cat in a box could be in an uncertain predicament.
Compared to the second most famous, but ironically similar: "Does this dress make me look fat?"
Where your relationship is also in an "uncertain predicament" -- being both dead and alive -- until the question is answered.
It must have been something you assimilated. . . .
The whole point of the Schrodinger's cat thought experiment was that quantum physics can apply to large scale things like cats and people, indirectly, if you design a mechanism to make it so. It's not about the whole cat decaying. The experiment is that if a geiger counter detects a single atom decaying it triggers the release of a poison to kill the cat. Thus the quantum state of the single atom determines the life or death of the cat.
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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.
The whole point of Schrodinger's cat experiment was to show that trying to apply certain quantum physics theories to reality resulted in absurd results.
To him (and Einstein), it was obvious that the cat could not be both alive and dead, and therefore the people pushing the superposition theory were obviously wrong.
It's a shame that his thought experiment has been taken to mean the exact opposite of what he was originally talking about.
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?"
Until we open up Schrödinger's coffin, we can't know whether he was arguing for or against the Copenhagen interpretation.
This is my signature. There are many like it, but this one is mine.
"Conscious observer" has nothing to do with it. The Geiger counter rigged to the poison is the observer that collapses the wave state.
Socialism: a lie told by totalitarians and believed by fools.
Because he could be spinning in his grave in either direction. (sorry).
Where are we going and why are we in a handbasket?
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?
I believe you are mistaken.
Schrödinger’s point was that the Copenhagen Interpretation led to absurd conclusions. See below.
https://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat#Origin_and_motivation
Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics. However, since Schrödinger's time, other interpretations of the mathematics of quantum mechanics have been advanced by physicists, some of which regard the "alive and dead" cat superposition as quite real. Intended as a critique of the Copenhagen interpretation, the Schrödinger's cat thought experiment remains a defining touchstone for modern interpretations of quantum mechanics.[citation needed] Physicists often use the way each interpretation deals with Schrödinger's cat as a way of illustrating and comparing the particular features, strengths, and weaknesses of each interpretation.[citation needed]
You are correct.
And, by "measurement," we don't mean "humans looking at it."
The "measurement problem" was settled long ago in that there are a shit load of "measuring devices."
When a quantum interacts with anything , that's a measurement.
It little behooves the best of us to comment on the rest of us.
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.
The mathematical equation are still used. What your itnerpret them as MW, copenhagen wave collapse , or angel on a pin is pretty much unfalsifiable. Among my colleague copenhagen is still the majorly used interpretation , just look at QM article they speak of measurement and collapse. Not other world or angel on a pin.
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If you believe that, you haven't taken a single course in quantum mechanics. Copenhagen interpretation is still taught as the orthodox interpretation of quantum mechanics—maybe everyone has an issue with the whole idea of non-local collapse of wavefunction (or what makes up a "measurement"), but it's more widely believed than any of the other cooky theories, including some that Einstein proposed.
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.
Look up Bell's theorem.
FFS the linked article didn't mention the original paper, thank goodness they even mentioned the authors. After tracking down the authors publications, I have located the original paper on arxiv. It's interesting to read, and seems to lend more thought experiment evidence to the many world interpretation.
Copenhagen interpretation is still taught as the orthodox interpretation of quantum mechanics
Perhaps in some of the more backward, remote realities, but it has long been abandoned in the more sophisticated worlds.
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.