8 ms·

Real-Life Schrödinger’s Cats Probe the Boundary of the Quantum World

76 points by digital55 8y ago

coldtea 8y ago
From the article... >Schrödinger’s point was not, as often implied, the apparent absurdity of quantum mechanics if extrapolated up to the everyday scale. And a few paragraphs down: >Schrödinger wanted to show how Bohr’s notion that nothing is fixed until it is measured could lead to logical absurdity if we imagined blowing entanglement up to everyday size.
- deleted 8y ago
  [deleted]
- baxtr 8y ago
  That’s Schrödinger’s cat right there in the article!
- deleted 8y ago
  [deleted]
- duxup 8y ago
  https://www.youtube.com/watch?v=t5MohK5FHEY https://www.youtube.com/watch?v=t5MohK5FHEY
- justicezyx 8y ago
  Do you mind to email this to the author and see how they respond?
- empath75 8y ago
  There’s a subtle difference between the two statements that is more clear if you read the entire article. He’s saying that Schrödinger didn’t think that _quantum mechanics_ in its entirety was absurd at everyday scales, only that the indeterminacy prior to measurement led to absurdities.
  - Koshkin 8y ago
    ... except that the cat was the measurement device...
    - blotter_paper 8y ago
      Correct me if I'm wrong, but I think you may be placing special importance on the cat as a measuring device because it is conscious (at least until poisoned). If we assumed that consciousness has nothing to do with measurement, and that two particles interacting is enough for decoherence of one particle relative to another, the cat isn't a measuring device any more than the many constituent atoms in a bucky ball are. If a bucky ball can be in a state of coherence, why not a cat? I know Schrödinger meant for his thought experiment to be obviously absurd, but I think he may have been underestimating the absurdity of the universe and thus accidentally proposing an entirely possible contraption that could not be feasibly built in his own time.
      - AnimalMuppet 8y ago
        The radiation detector is a valid measuring device. The hammer that smashes the vial of poison is a valid output device. The cat is a valid observer. But even the cat and the hammer are redundant - the radiation detector is enough.
- neonate 8y ago
  That's not a contradiction if his point was to criticize Bohr's notion of QM.
- kolpa 8y ago
  Right, Schrödinger’s point was that "wave-function collapse" is an absurd idea, not that macroscopic reality allows apparently-absurd situation.
sebringj 8y ago
Many Worlds helps explain how wave-particle duality could be plausible in some sense. How does one explain non locality????
- krastanov 8y ago
  This statement is a bit confused. The wave-particle duality is just a confusing and pretentious way of saying that both the model of using particles and the model of using waves are incomplete. They are incomplete because the correct (or at least more precise) model to describe nature, is to use quantum fields. This is a model that describe reality exactly at a vast range of scales. This is a model that supercede our old imprecise particle or wave models. The "many worlds" interpretation does nothing more than "interpret" this new confusing model in a way that is more palatable to our intuition.
  - sebringj 8y ago
    Absolutely confused, I agree. I cannot wrap my head around any of this. But to go further into the fog as it were, is there a fuzzy interpretation of non locality, meaning how can one work out "intuitively" how spooky action at a distance works out or is there a story of sorts to explain how a structure could encapsulate that?
    - Filligree 8y ago
      I never understood why non-locality is a problem to begin with. I mean, are we assuming that the universe is implemented on an infinite grid of computers, or what? (...which, before you get any ideas, I don't think would work with relativity.) Is there any reason to filter out nonlocal theories beyond vague notions of aesthetics?
      - kolpa 8y ago
        Einstein's theory of relativity is in large part a simple statement that the Universe has a speed limit (the speed of light), and all the complex and amazing facts that entails. If they Universe doesn't have a speed limit after all, how is that everywhere we look there appears to be a speed limit, except in certain corners? How does the speed limit not hold in non-local action, and what prevents non-local action from making every thing else avoid the speed limit?
monktastic1 8y ago
> If you simply stick a cat in a box and link its fate to the outcome of some quantum event, you’re not likely to put it in a superposition of alive and dead, because decoherence will almost instantly force it into one state or the other. This is a non-sequitur. Decoherence will not force it into one state, but merely prevent us (in practice, but crucially not in principle) from detecting interference between the two states. It is still in a superposition. When am I required to stop treating it as a superposition? When it entangles with me. From the MWI perspective, there are then two copies of me, and each must say that there is no superposition. In other words, from "my" perspective, the superposition ends precisely with me. Which part of "me"? My toe? My nose? No, clearly it has something to do with my consciousness. A materialist might say that consciousness is a strictly physical process, and when the relevant components entangle with the system, that is when the superposition ends (from my perspective). An idealist might say that consciousness is the very fabric of reality, and so it's obvious that "becoming conscious of an outcome" and that outcome becoming real are one and the same event. Nonetheless, once this happens, nobody in "my world" can demonstrate interference, even in principle. In this precise sense, you do occupy a unique role in what you call "your world."
- Koshkin 8y ago
  Even though it is possible to treat macroscopic objects as quantum systems, the science of quantum mechanics finds it necessary to continue to treat them classically; it is an interaction of a quantum particle with a classical object that constitutes "measurement." The cat is merely such a measurement device.
  - monktastic1 8y ago
    But crucially, it is two branches, each evolving classically. It is true that this system will obey the same statistics as a classically indeterminate one, but claiming that it's now a single classical system is disingenuous. It's a great place to sweep the measurement problem under the rug.
5DFractalTetris 8y ago
Ain't this me?
asafira 8y ago
Hey everyone! This is similar to work I do in my PhD. Feel free to ask me any questions! (I believe Ralf, the first author of the paper cited in the article, will likely come to my group for a postdoc)
- dsmithatx 8y ago
  I wonder, is there any science that making conscious decisions could be related to quantum mechanics? The mechanics of both feel similar to me.
  - imh 8y ago
    The connection between consciousness and quantum mechanics is in the same realm as chemtrails and homeopathy.
    - dsmithatx 8y ago
      As were the connections between energy, time, and mass not so long ago.
    - monktastic1 8y ago
      Not quite. The measurement problem only exists because of this recognition that I only experience one outcome. The key word is experience. Contrary to the author's loose writing, Schrodinger's Cat (and environment) is in a superposition before it entangles with me. Decoherence (which is just a name for really complicated entanglement) does not change that; it only makes it hard to demonstrate the superposition. And yet, after I entangle with it, I am no longer free to treat the system as a superposition. If you try to pin down when "I entangle with it," you will notice yourself trying to make precise when "I experience it." Clearly these problems are linked. To quote Ed Witten: > I’m not going to attempt to define consciousness, in a way that’s connected with the fact that I don’t believe it will become part of physics. And that has to do, I think, with the mysteries that bother a lot of people about quantum mechanics and its applications to the universe. > Quantum mechanics kind of has an all-embracing property, that to completely make sense it has to be applied to everything in sight, including ultimately, the observer. But trying to apply quantum mechanics to ourselves makes us extremely uncomfortable. Especially because of our consciousness, which seems to clash with that idea. So we’re left with a disquiet concerning quantum mechanics, and its applications to the universe. And I do not believe that disquiet will go away. If anything, I suspect that it will acquire new dimensions.

76 points by digital55 8y ago

From the article... >Schrödinger’s point was not, as often implied, the apparent absurdity of quantum mechanics if extrapolated up to the everyday scale. And a few paragraphs down: >Schrödinger wanted to show how Bohr’s notion that nothing is fixed until it is measured could lead to logical absurdity if we imagined blowing entanglement up to everyday size.

deleted 8y ago
[deleted]
baxtr 8y ago
That’s Schrödinger’s cat right there in the article!
deleted 8y ago
[deleted]
duxup 8y ago
https://www.youtube.com/watch?v=t5MohK5FHEY https://www.youtube.com/watch?v=t5MohK5FHEY
justicezyx 8y ago
Do you mind to email this to the author and see how they respond?
empath75 8y ago
There’s a subtle difference between the two statements that is more clear if you read the entire article. He’s saying that Schrödinger didn’t think that _quantum mechanics_ in its entirety was absurd at everyday scales, only that the indeterminacy prior to measurement led to absurdities.
- Koshkin 8y ago
  ... except that the cat was the measurement device...
  - blotter_paper 8y ago
    Correct me if I'm wrong, but I think you may be placing special importance on the cat as a measuring device because it is conscious (at least until poisoned). If we assumed that consciousness has nothing to do with measurement, and that two particles interacting is enough for decoherence of one particle relative to another, the cat isn't a measuring device any more than the many constituent atoms in a bucky ball are. If a bucky ball can be in a state of coherence, why not a cat? I know Schrödinger meant for his thought experiment to be obviously absurd, but I think he may have been underestimating the absurdity of the universe and thus accidentally proposing an entirely possible contraption that could not be feasibly built in his own time.
    - AnimalMuppet 8y ago
      The radiation detector is a valid measuring device. The hammer that smashes the vial of poison is a valid output device. The cat is a valid observer. But even the cat and the hammer are redundant - the radiation detector is enough.
neonate 8y ago
That's not a contradiction if his point was to criticize Bohr's notion of QM.
kolpa 8y ago
Right, Schrödinger’s point was that "wave-function collapse" is an absurd idea, not that macroscopic reality allows apparently-absurd situation.

sebringj 8y ago

Many Worlds helps explain how wave-particle duality could be plausible in some sense. How does one explain non locality????

krastanov 8y ago
This statement is a bit confused. The wave-particle duality is just a confusing and pretentious way of saying that both the model of using particles and the model of using waves are incomplete. They are incomplete because the correct (or at least more precise) model to describe nature, is to use quantum fields. This is a model that describe reality exactly at a vast range of scales. This is a model that supercede our old imprecise particle or wave models. The "many worlds" interpretation does nothing more than "interpret" this new confusing model in a way that is more palatable to our intuition.
- sebringj 8y ago
  Absolutely confused, I agree. I cannot wrap my head around any of this. But to go further into the fog as it were, is there a fuzzy interpretation of non locality, meaning how can one work out "intuitively" how spooky action at a distance works out or is there a story of sorts to explain how a structure could encapsulate that?
  - Filligree 8y ago
    I never understood why non-locality is a problem to begin with. I mean, are we assuming that the universe is implemented on an infinite grid of computers, or what? (...which, before you get any ideas, I don't think would work with relativity.) Is there any reason to filter out nonlocal theories beyond vague notions of aesthetics?
    - kolpa 8y ago
      Einstein's theory of relativity is in large part a simple statement that the Universe has a speed limit (the speed of light), and all the complex and amazing facts that entails. If they Universe doesn't have a speed limit after all, how is that everywhere we look there appears to be a speed limit, except in certain corners? How does the speed limit not hold in non-local action, and what prevents non-local action from making every thing else avoid the speed limit?

monktastic1 8y ago

> If you simply stick a cat in a box and link its fate to the outcome of some quantum event, you’re not likely to put it in a superposition of alive and dead, because decoherence will almost instantly force it into one state or the other. This is a non-sequitur. Decoherence will not force it into one state, but merely prevent us (in practice, but crucially not in principle) from detecting interference between the two states. It is still in a superposition. When am I required to stop treating it as a superposition? When it entangles with me. From the MWI perspective, there are then two copies of me, and each must say that there is no superposition. In other words, from "my" perspective, the superposition ends precisely with me. Which part of "me"? My toe? My nose? No, clearly it has something to do with my consciousness. A materialist might say that consciousness is a strictly physical process, and when the relevant components entangle with the system, that is when the superposition ends (from my perspective). An idealist might say that consciousness is the very fabric of reality, and so it's obvious that "becoming conscious of an outcome" and that outcome becoming real are one and the same event. Nonetheless, once this happens, nobody in "my world" can demonstrate interference, even in principle. In this precise sense, you do occupy a unique role in what you call "your world."

Koshkin 8y ago
Even though it is possible to treat macroscopic objects as quantum systems, the science of quantum mechanics finds it necessary to continue to treat them classically; it is an interaction of a quantum particle with a classical object that constitutes "measurement." The cat is merely such a measurement device.
- monktastic1 8y ago
  But crucially, it is two branches, each evolving classically. It is true that this system will obey the same statistics as a classically indeterminate one, but claiming that it's now a single classical system is disingenuous. It's a great place to sweep the measurement problem under the rug.

5DFractalTetris 8y ago

Ain't this me?

asafira 8y ago

Hey everyone! This is similar to work I do in my PhD. Feel free to ask me any questions! (I believe Ralf, the first author of the paper cited in the article, will likely come to my group for a postdoc)

dsmithatx 8y ago
I wonder, is there any science that making conscious decisions could be related to quantum mechanics? The mechanics of both feel similar to me.
- imh 8y ago
  The connection between consciousness and quantum mechanics is in the same realm as chemtrails and homeopathy.
  - dsmithatx 8y ago
    As were the connections between energy, time, and mass not so long ago.
  - monktastic1 8y ago
    Not quite. The measurement problem only exists because of this recognition that I only experience one outcome. The key word is experience. Contrary to the author's loose writing, Schrodinger's Cat (and environment) is in a superposition before it entangles with me. Decoherence (which is just a name for really complicated entanglement) does not change that; it only makes it hard to demonstrate the superposition. And yet, after I entangle with it, I am no longer free to treat the system as a superposition. If you try to pin down when "I entangle with it," you will notice yourself trying to make precise when "I experience it." Clearly these problems are linked. To quote Ed Witten: > I’m not going to attempt to define consciousness, in a way that’s connected with the fact that I don’t believe it will become part of physics. And that has to do, I think, with the mysteries that bother a lot of people about quantum mechanics and its applications to the universe. > Quantum mechanics kind of has an all-embracing property, that to completely make sense it has to be applied to everything in sight, including ultimately, the observer. But trying to apply quantum mechanics to ourselves makes us extremely uncomfortable. Especially because of our consciousness, which seems to clash with that idea. So we’re left with a disquiet concerning quantum mechanics, and its applications to the universe. And I do not believe that disquiet will go away. If anything, I suspect that it will acquire new dimensions.