Quantum uncertainty, and Schrodinger's cat

[Angra Mainyu]

And the camera sn't, because you choose not to say that it is?

No. I'm saying that the camera isn't because you and Unter- suggested putting it in the box to record for later playback. Which incidentally shows that neither of you understood what the thought experiment was intended to be about.

I didn't make that suggestion, but replied to your reply about it.
But regardless, a key question is: what determines what is part of the system under observation? But I already raised that question and corresponding objections in much greater detail, and you replied dismissively, failing to see the problems in your interpretation of the CI.

So, let's say that there are two cats in the box, Garfield and Felix (replace them by humans if you doubt cats can be observers)
Will they be dead/alive?
Your reply seems to imply that if they're both part of the system under test, then yes, they would both be dead/alive. But if only Felix of them is a part of the system under test, then no, because the Garfield collapses the wave function.

But of course, they can be both part of the system labeled "under test" by Bob, but not part of the system labeled "under test" by Alice. And the point is that what set of objects Bob or Alice labels "under test" has nothing to do with what the cats are experiencing, if anything - nothing if they're dead -, or whether they're dead or alive.

For that matter, let's say that Jack and Jill are now in the box. So, you say that the system under test includes Jack and Jill, so they're both dead/alive. But - alas - Jill decided to consider only the system including the rest of the box but herself, so she became and observer, collapsed the wave function, and died - despite the fact that you would keep committed to the belief that she's dead/alive, as your system includes Jill.

For that matter, go back to the single-cat experiment. You say that the cat is part of the system under test. Suppose the experiment is actually carried out, and no one opens the box, but I just declare that the cat is no longer part of the system under test. Then, by what you seem to be saying, I ought to conclude that now the cat collapses the wave function, so it's either dead, or alive.

All illustrating that you still don't understand what the thought experiment is intended to say about quantum uncertainty.

No, your reply illustrates your failure to address my questions and objections, and provides good grounds for believing you don't understand them (see below). I'm not even talking about the original experiment. I'm talking about the claims in your posts (if you didn't mean to make claims about what actually would happen, then fine: I'm talking about your claims about what CI claims would happen).

They are not my claims. Personally, I don't particularly care for the Copenhagen interpretation. What I was saying is what the those who do claim would happen in the thought experiment.

Alright, then that was a misunderstanding. But then my replies work as questions and/or objections to your interpretation (based on the part of your interpretation you explained) of the Copenhagen Interpretation (CI).

Again you are showing that you don't understand the thought experiment and its purpose.

Again, you fail to address decisive objections to your claims. Perhaps, because you don't understand how my questions and objections challenge your interpretation of the Copenhagen Interpretation (based on your description).

The designer of the thought experiment determines what the system under test is. In this thought experiment, the designers specifically designed the test for the purpose of having the cat as part of the system under test.

That replies simply misses my point entirely.

Suppose that someone actually makes those devices. Who or what determines what counts as part of the "system under test"?

Furthermore, we may stipulate that the box, etc., was not designed for a single purpose. One of the people making the device wanted to make it so that the camera, Jill and Jack were all part of the sytem under observation. Another one of the people making it, did so intending to make it so that Jack and Jill were, but not the camera. A third designer/maker didn't intend that Jill be part of the system under observation.

So, are Jill and Jack in a state of dead/not dead, according to your interpretation of CI?

For example, let's say that Jill and Jack and a camera are inside the box - let's say it's a real box.
So, Linda declares that all three objects are part of the system under test. George declares that Jill and Jack are, but not the camera. Dick says that Jill is not part of the system under test.

After Linda, George and Dick have made their statements, are Jill and Jack dead/alive - their state is indeterminate - or are they not? (side note: if you tell me it depends on the experiment or something like that, I will ask you what you claim is really going on: are Jill and Jake experiencing things, or are they perhaps not (because they died after collapse)?).

I have no idea what the fuck you are talking about but it has nothing to do with the thought experiment or its intent.

The first part of your sentence appears to be correct: given your responses and your failure to see the force of my objections even after all this time, it appears likely that you have no idea what I'm talking about.

Well, I'm asking questions and raising objections to what you described as [part of] the Copenhagen Interpretation. I make no claims that any of my points does any damage to the actual Copenhagen Interpretation, or that your interpretation of the Copenhagen Interpretation is correct or incorrect. I'm just debunking what you described as such.

I have made no personal claims, only described what the thought experiment is about.

Okay, so there was a misunderstanding with regard to whether you were making claims about what would happen to the cat. But that aside, if you only gave your description of the thought experiment (and of the relevant part of the CI), then I have asked several questions and raised several objections to what you described as [part of] the Copenhagen Interpretation. But in light of your replies, it seems very probable that you have not understood my objections, or the point of my questions (i.e., how the questions would lead to decisive problems).

 

[skepticalbip]

............blather.................

Until you gain some understanding of the interpretations held by physicists of quantum uncertainty, this seems like a complete waste of time.

But to get to the bases of your ramblings, if you introduce an observer then the quantum event will be different than if there is no observer. An "observer" is anything that would allow the experimenter to see quantum events like the path of a particle, etc. as in the double slit experiment, etc. So when you throw in people to observe, cameras, brain scans, etc. anything to let the experimenter determine what quantum uncertainty is hiding from him then you will change the event and what he wanted to see, he won't. (again read up on the double slit experiment)

The cat in the box was a thought experiment to illustrate entangled superposition between a quantum event and a macro object. If there is anything, ANYTHING, introduced (an observer) to verify or disprove this then there will be no superposition because the observer will collapse the wave function.

All your ramblings are based on what you would expect to see in our everyday world so have nothing to do with quantum weirdness or physicists attempts to understand it.

 

[Kharakov]

I strayed from MWI, and was speculating that specific branches (worlds) are trimmed when an observer witnesses something (cat is dead or alive, 2 branches). Definitely not a full MW interpretation- instead there are MWs until a specific branch is forced to be chosen by observation.

Isn't every branch of the MW universe supposed to be an expression of every possible outcome regardless of any particular observer? In other words, all of the versions of 'you' being the subjects (or is that articles) of all possible combinations of each and every event in your lifetime?

Yup. I was thinking of a MW that was steadily trimmed, like someone trimming a tree to cause it to grow in a desired way instead of letting it grow wild. In other words, not every potential W exists, because certain branches are steadily trimmed off.

 

[Angra Mainyu]

............blather.................

Until you gain some understanding of the interpretations held by physicists of quantum uncertainty, this seems like a complete waste of time.

But to get to the bases of your ramblings, if you introduce an observer then the quantum event will be different than if there is no observer. An "observer" is anything that would allow the experimenter to see quantum events like the path of a particle, etc. as in the double slit experiment, etc. So when you throw in people to observe, cameras, brain scans, etc. anything to let the experimenter determine what quantum uncertainty is hiding from him then you will change the event and what he wanted to see, he won't. (again read up on the double slit experiment)

The cat in the box was a thought experiment to illustrate entangled superposition between a quantum event and a macro object. If there is anything, ANYTHING, introduced (an observer) to verify or disprove this then there will be no superposition because the observer will collapse the wave function.

All your ramblings are based on what you would expect to see in our everyday world so have nothing to do with quantum weirdness or physicists attempts to understand it.

Your derogatory language (e.g., "ramblings", "blather") is quite insulting, but doesn't change the fact you don't even understand what I'm talking about, and fail to realize the problems for your interpretation of the Copenhagen Interpretation.
My arguments are not based on what I would expect to see in our everyday world, and your claim that they are (while calling them "ramblings") is unjustified because - again - you don't even understand my arguments. In fact, my arguments are based on what you described as the CI. What we would expect to see doesn't matter. You're still failing to understand the points, even though I made them clear enough so that someone actually paying attention instead of dismissing them beforehand would get them - and if some part is unclear, asking for clarification would help. But you're not even engaging my arguments. Whatever.

 

[barbos]

Isn't every branch of the MW universe supposed to be an expression of every possible outcome regardless of any particular observer? In other words, all of the versions of 'you' being the subjects (or is that articles) of all possible combinations of each and every event in your lifetime?

Yup. I was thinking of a MW that was steadily trimmed, like someone trimming a tree to cause it to grow in a desired way instead of letting it grow wild. In other words, not every potential W exists, because certain branches are steadily trimmed off.

I understand your thought process, but you you have to ask yourself who is doing the trimming?
Beauty of MWI is that it is both deterministic and nondeterministic. By proposing trimming you effectively reduce MWI to Copenhagen Interpretation with its wave-function collapse (trimming=collapse)

 

[Testy Calibrate]

"Those who are not shocked when they first come across quantum theory cannot possibly have understood it."
~ Niels Bohr.

Whether a cat can be both alive and dead is a matter for biology not physics.

But all one has to do is produce a cat that is both alive and dead to demonstrate my error.

http://www.newscientist.com/article...ects-seen-in-visible-object.html#.VQvY_I4XutM

 

[Testy Calibrate]

https://medium.com/the-physics-arxi...record-for-wave-particle-duality-462c39db8e7b

 

[Speakpigeon]

For example, I don't think that QM explicitly tells you that there is just one cat (in two incompatible states), or even that there is any cat (for example, there are maybe two wave functions but no actual cat). In all the descriptions and explana-tions I have looked at, not one scientist ever insisted that, actually, there would be one cat in two incompatible states. This formulation seems to appear as a sort of sloppy short-cut for saying that there are two wave functions. In other words, the "one cat, two states" is not science, it's just sloppy wording from scientists.

A Mr. Serge Haroche, the 2012 Nobel prize for physics for his work on Quantum Physics--so somebody presumably who knows something about QM--in a March 2013 interview on Nicolas Gisin's crucial experiment in Geneva where two macroscopic bits of neodymium crystals (10⁶ atoms) were effectively entangled--says, and I quote, "un atome peut être à la fois dans un état excité et non excité comme le chat dans l'expérience de Schrödinger : celui-ci peut se trouver dans un état où il est à la fois mort et vivant." See!?

Oops, solly, that is French!

Ok, so here is my translation for the ignoramus here who don't speak French:

"An atom can be both in an excited and a non-excited state like the cat in Schrödinger's experiment, which can be in a state where it is both dead and alive."​

No wonder the public gets confused. Confused about science in general.
EB

 

[Speakpigeon]

I don't claim to understand quantum weirdness. I just recognize and acknowledge that it is there. If either of you can explain the double slit experiment and/or quantum weirdness, in general, then there is a Nobel Prize waiting for you. Refusing to accept quantum weirdness because you don't understand it (no one does yet) is only refusal to accept reality.

There is double slit weirdness with particles and then there is interpretation on how that weirdness will effect something on the scale of a cat.

People can consider weird the result of the double slit experiment but it is still the case that there is no logical problem with it whatsoever: Different experimental conditions produce different results. No big deal. The fact that some people do make logically problematic claims about these results doesn't imply anything about them.

All we have is interpretation, not evidence.

We can have acceptable evidence like in other scientific experiments by putting a camera inside the box, as already suggested. When we open the box, if the cat is dead we will see that the death of the cat has been recorded by the camera at some time before the opening of the box. If the cat is still alive when we open the box, all that the camera recording will show will be a cat alive until the box is opened (once the box is open the cat will bolt). A camera cannot help.
EB

 

[untermensche]

There is double slit weirdness with particles and then there is interpretation on how that weirdness will effect something on the scale of a cat.

People can consider weird the result of the double slit experiment but it is still the case that there is no logical problem with it whatsoever: Different experimental conditions produce different results. No big deal. The fact that some people do make logically problematic claims about these results doesn't imply anything about them.

The double slit experiments are called weird because on our scale we don't see these kinds of effects. We evolved to survive on this scale and respond to the world as it appears on this scale.

And yes, logic does not apply to the workings of nature. It is not "logical" that a ball falls to the earth when dropped. It is just the way it is.

All we have is interpretation, not evidence.

We can have acceptable evidence like in other scientific experiments by putting a camera inside the box, as already suggested. When we open the box, if the cat is dead we will see that the death of the cat has been recorded by the camera at some time before the opening of the box. If the cat is still alive when we open the box, all that the camera recording will show will be a cat alive until the box is opened (once the box is open the cat will bolt). A camera cannot help.
EB

I think you meant to say we can NOT have evidence.

The question is really about limits. With the speed of light we at least, so far, see a limit on the natural world.

Is there a limit on Quantum superposition and other Quantum effects? To what scale do they extend? All scales?

 

[skepticalbip]

There is double slit weirdness with particles and then there is interpretation on how that weirdness will effect something on the scale of a cat.

People can consider weird the result of the double slit experiment but it is still the case that there is no logical problem with it whatsoever: Different experimental conditions produce different results. No big deal. The fact that some people do make logically problematic claims about these results doesn't imply anything about them.

Logic isn't the problem. The problem is understanding. Science seeks to understand that which we don't yet understand. Exactly how is it that the electron in a double slit experiment behaves as a particle when we try to watch it and like a wave when we don't? The Nobel committee is waiting for someone to answer that question. Obviously there are quite a few pretty sharp physicists trying to answer this question so any "obvious" answer has likely already been tested.

All we have is interpretation, not evidence.

We can have acceptable evidence like in other scientific experiments by putting a camera inside the box, as already suggested. When we open the box, if the cat is dead we will see that the death of the cat has been recorded by the camera at some time before the opening of the box. If the cat is still alive when we open the box, all that the camera recording will show will be a cat alive until the box is opened (once the box is open the cat will bolt). A camera cannot help.
EB

Putting a camera in the box as an observer voids the thought experiment. The thought experiment is all about quantum weirdness, which changes when there is an observer (see the double slit experiment above). Your logical solution in this case is assuming that it doesn't

 

[Kharakov]

Yup. I was thinking of a MW that was steadily trimmed, like someone trimming a tree to cause it to grow in a desired way instead of letting it grow wild. In other words, not every potential W exists, because certain branches are steadily trimmed off.

I understand your thought process, but you you have to ask yourself who is doing the trimming?

Some consciousness that is aware of possible outcomes. Like when you decide to eat food from a beat up taco truck...

Beauty of MWI is that it is both deterministic and nondeterministic. By proposing trimming you effectively reduce MWI to Copenhagen Interpretation with its wave-function collapse (trimming=collapse)

Trimming != collapse, it specifically represents that only so many worlds of the MWI are allowed to grow. It's a lesser infinite than the full set of MWI.

Focus on one set of circumstances from the MWI and you'd get this conversation. blerg bloop blurp.

 

[DBT]

As I think I understand it, MWI doesn't involve wave collapse, all possible/probable outcomes are played out in split off universes...branches forming branches, forming branches, ad infinitum.

 

[barbos]

I understand your thought process, but you you have to ask yourself who is doing the trimming?

Some consciousness that is aware of possible outcomes. Like when you decide to eat food from a beat up taco truck...

That's too complicated, unnecessary and really not an explanation at all.

Beauty of MWI is that it is both deterministic and nondeterministic. By proposing trimming you effectively reduce MWI to Copenhagen Interpretation with its wave-function collapse (trimming=collapse)

Trimming != collapse, it specifically represents that only so many worlds of the MWI are allowed to grow. It's a lesser infinite than the full set of MWI.

OK, trimming=partial collapse (by some other consciousness )

Focus on one set of circumstances from the MWI and you'd get this conversation. blerg bloop blurp.

What?

 

[DBT]

What about the physical evolution of the universe before the existence of a mind/observer? Or is someone proposing quantum consciousness?

 

[Underseer]

Schrodinger's cat is a criticism of the Copenhagen interpretation. Since cats obviously can't be both alive and dead, the thought experiment is meant to highlight why the Copenhagen interpretation is silly.

Of course, I think it's a bad analogy because in the thought experiment, the "observer" is either the petri dish or the cat, not the human who opens the box.

 

[bilby]

Schrodinger's cat is a criticism of the Copenhagen interpretation. Since cats obviously can't be both alive and dead, the thought experiment is meant to highlight why the Copenhagen interpretation is silly.

Of course, I think it's a bad analogy because in the thought experiment, the "observer" is either the petri dish or the cat, not the human who opens the box.

Oh, really? Then why didn't the cat get the Nobel Prize, if she was the observer?

Honestly, bloody sexists. It's Lise Meitner all over again.

 

[skepticalbip]

Schrodinger's cat is a criticism of the Copenhagen interpretation. Since cats obviously can't be both alive and dead, the thought experiment is meant to highlight why the Copenhagen interpretation is silly.

Of course, I think it's a bad analogy because in the thought experiment, the "observer" is either the petri dish or the cat, not the human who opens the box.

The Copenhagen interpretation has nothing to do with cats or entanglement. It is an interpretation of the meaning of quantum uncertainty. It takes Schrodinger's wave function literally as meaning that all possible states exist simultaneously while Schrodinger meant it as a mathematical tool to calculate the probability of the state.

Schrodinger’s thought experiment was intended to show the absurdity of that interpretation. However, the supporters of the interpretation said that, since the state of the cat was solely dependent on the state of the decay process, the state of the cat was entangled with it. If the quantum uncertainty says that the state of the decay process exists in all possible states (superposition) then, since the cat’s state is entangled with it, the cat’s state is in all possible states, a state of entangled superposition.

ETA:
It is a thought experiment that can not be actually carried out. It is like Einstein's thought experiment of riding on a photon to see what the universe looks like from that perspective. Such experiments allow us to mentally test ideas to see where they take us. Einstein's led to the theory of relativity. Whether this one will lead anywhere is, as yet, not known.

 

[Kharakov]

Someone explain to me again how the detector, which observes whether the atom decayed, does not detect whether the atom decays and collapse the state of the whole system...

 

[Underseer]

Schrodinger's cat is a criticism of the Copenhagen interpretation. Since cats obviously can't be both alive and dead, the thought experiment is meant to highlight why the Copenhagen interpretation is silly.

Of course, I think it's a bad analogy because in the thought experiment, the "observer" is either the petri dish or the cat, not the human who opens the box.

The Copenhagen interpretation has nothing to do with cats or entanglement. It is an interpretation of the meaning of quantum uncertainty. It takes Schrodinger's wave function literally as meaning that all possible states exist simultaneously while Schrodinger meant it as a mathematical tool to calculate the probability of the state.

Schrodinger’s thought experiment was intended to show the absurdity of that interpretation. However, the supporters of the interpretation said that, since the state of the cat was solely dependent on the state of the decay process, the state of the cat was entangled with it. If the quantum uncertainty says that the state of the decay process exists in all possible states (superposition) then, since the cat’s state is entangled with it, the cat’s state is in all possible states, a state of entangled superposition.

ETA:
It is a thought experiment that can not be actually carried out. It is like Einstein's thought experiment of riding on a photon to see what the universe looks like from that perspective. Such experiments allow us to mentally test ideas to see where they take us. Einstein's led to the theory of relativity. Whether this one will lead anywhere is, as yet, not known.

I have to disagree.

When we take a measurement, it's not the scientist that is the observer, it's the measuring device. The measuring device is interacting with whatever it is you're measuring, and that's what causes the collapse of the wave function. The scientist reading the dial is not what causes the collapse of the wave function. So in the Schrodinger's cat example, once a quantum state starts a chemical reaction in the petri dish, then the damn petri dish is the measuring device that causes the collapse of the wave function. By the time the chemical reaction starts, the chain of events has entered the macroscopic world. The person opening the box is the equivalent of a scientist looking at a dial on a measuring device.