Quantum Measurements Leave Schrödinger's Cat Alive 210
First time accepted submitter Walking The Walk writes "Your co-workers who keep using Schrödinger's cat metaphor may need to find a new one. New Scientist reports that 'by making constant but weak measurements of a quantum system, physicists have managed to probe a delicate quantum state without destroying it – the equivalent of taking a peek at Schrodinger's metaphorical cat without killing it. The result should make it easier to handle systems such as quantum computers that exploit the exotic properties of the quantum world.'"
I want a refund, Slashdot (Score:4, Funny)
The SchrÃdinger's Cat [thinkgeek.com] I bought from Think Geek keeps dying half the time.
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I prefer Schrödinger's Fridge. [angryflower.com]
I don't know if everyone is joking (well, the cartoonist who drew that linked cartoon isn't serious) or everyone misunderstands the concept that whoever does the Bob cartoons is poking fun at. It simply means "you don't know unless you test". The idea that a cat is both alive and dead is ludicrous.
The cat is alive... (Score:4, Funny)
and extremely pissed off about your experiment.
http://afternoonsnoozebutton.com/post/9395842065/breaking-news-schrodingers-cat-is-alive-and [afternoons...button.com]
The BEST related animation (Score:5, Interesting)
Not my Work! - HEX
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The drawings were decent (except for the hands, the mark of a great cartoonist), but I hate shitty animations that bounce around. The story itself was a simplistic revenge story and uninteresting.
The real representative line from TFA (Score:4, Informative)
So, in essence, the main thing they found out is how to do more stuff with qbits without triggering a collapse of the wavelength function.
Real summary:
Obscure need which is somehow quantum computing, but not in any way feline, related gets obscure advance.
Shachar
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Can I have my Nobel prize now please?
Quantum cryptography? (Score:5, Interesting)
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Came here to see this point made, was not disappoint.
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What? Isn't the proven destructiveness of measuring a quantum system the bedrock of quantum key distribution [wikipedia.org]?
I thought I remembered a recent story saying that researchers had found a method to "peek" at an quantum-encoded message without tipping Bob and Alice off to the fact that they had an eavesdropper. I wonder if this story is related to that.
Re:Quantum cryptography? (Score:4, Informative)
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I thought at this point is had become obvious that quantum cryptography was just a nice scam to fund fundamental physics research?
We shouldn't need to scam anyone to fund fundamental physics research.
But we do...politicians (Score:3)
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If an object the mass of a cat and composed of normal matter can exist as a quantum superposition, then mass and particle complexity are not fundamental limits. If the cat is possible, the Planet Jupiter can also exist in a Schrodinger's Cat like state.
Then there's the question of what constitutes an observer. Mystical models assume something that is itself aware. The extreme antropomrphic end of observer definitions is "a being capable of understanding the implcations of
The cat is dead (Score:2)
If the cat isn't dead now, it will be eventually. So you might as well assume it's dead and move on.
We have to name it... (Score:5, Funny)
Can we PLEASE call it a Heisenberg Compensator?
whodathunkit? (Score:3)
every time ... (Score:5, Funny)
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Every time they take a peek, God kills a kitten.
Only if the kitten is entangled with the cat in the box.
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He entangles us all in His noodley appendages.
Looks like Schrodingers Cat stayed alive (Score:2, Offtopic)
just long enough to be eaten by Pavlov's Dog
Entangled Garments (Score:4, Funny)
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Go, look in your closet. Did you buy all those hangars? No! Most of them used to be your socks.
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Two words: Bertlmann's socks [cdsweb.cern.ch].
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It works out when you take into consideration socks come in pairs. CP violation states that you will get back a full pair most of the time, but occasionally, you will only get one.
Copenhagen Interpretation (Score:2)
Re:Copenhagen Interpretation (Score:4, Insightful)
1. Stop being a jerk
2. Look up the work on collapse of interference in the double slit experiment.
3. If you can determine conclusively what constitutes an observation of a quantum system, you will be in line for a big prize.
4. Ignore any discussion of cats. It is a joke that everyone has fallen for.
New Scientist? (Score:5, Informative)
http://www.nature.com/nature/journal/v490/n7418/full/nature11505.html [nature.com]
Observing, Not Avoiding (Score:5, Interesting)
From the abstract:
"The act of measurement bridges the quantum and classical worlds by projecting a superposition of possible states into a single (probabilistic) outcome. The timescale of this 'instantaneous'process can be stretched using weak measurements usuch that it takes the form of a gradual random walk towards a final state. Remarkably, the interim measurement record is sufficient to continuously track and steer the quantum state using feedback..."
The way I read this, they aren't claiming they prevented collapse, nor that they can predict which state it will collapse to; rather, they have (1) increased the time of the collapse of the wave function (via feedback) and (2) been able to "watch" the electron collapse to whichever state it goes to. [N.B.: I am totally open to correction. I haven't paid the $32 for a copy of the paper.]
So, no Heisenberg compensator here.
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That said, IANA Physicist
Unfortunately... (Score:2)
Does this imply FTL comms? (Score:2)
If the state of an entangled set of quantum bits can be known in advance and their states observed without collapsing them, then it stands to reason that a remote communications station with a pre-delivered set of pre-entangled bits could receive a message by observing the collapse the instant the 'transmitter' causes it to happen.
I wonder if this research provides this possibility, or if there is something inherent to the entanglement/observation process that prevents this.
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i believe the problem is that it might be possible to know what it will collapse into, but we still can't influence how it will collapse.
so the receiver will know it will likely collapse into state X before actually measuring it...how does that really help anything? you are just sort of measuring it earlier.
Headline? (Score:3)
Quantum Measurements Leave Schrödinger's Cat Alive
Shouldn't that be "Quantum Measurements Leave Schrödinger's Cat In A Superposition Of Alive And Dead"? If it's decidedly alive then the waveform has collapsed, and isn't that what they're avoiding? (did not read TFA)
Who cares? (Score:2)
This is interesting, but the title is misleading. (Score:3, Insightful)
Schrodinger's Cat (Score:2)
Yep, completely rewritten! (Score:3)
If you're leaveing it alive ... (Score:2)
And for that matter, opening the box does not kill the cat, it just allows you to observe its state. We know that when you open the box there is a set probability of the cat being dead.
ITT Quantum Misconceptions (Score:2)
I barely understand Quantum Physics myself and I can tell that TFA makes all kinds of wild leaps in logic. Most of these thi
Re:Equivalent of peeking without killing it ?! (Score:5, Insightful)
Why is it equivalent of peeking without killing it ?!
The cat might already be dead when you peek. Now, apparantly you simply can peek at the cat's state.
I think you missed the whole point of the thought experiment. No, the cat is decidedly not already dead when you peeked. It is the moment of your peeking that picks a state for the cat.
Which, of course, means that the summary is meaningless. I'll go read TFA, and, more likely, then consult with a Physics Phd I know to try and make (relative) sense of this discovery.
Shachar
Re:Equivalent of peeking without killing it ?! (Score:4, Insightful)
I think perhaps you may be the one confused. The point of the thought experiment is that you cannot know whether the cat is alive or dead before opening the box. It's 50/50. In one interpretation of quantum mechanics that means that the cat exists in a combination of both states prior to observing it. Observing it causes one or the other of the states to prevail.
Re:Equivalent of peeking without killing it ?! (Score:5, Interesting)
No, that is not the experiment's point. That is its premise.
It is the only interpretation that I am aware of (though its precise phrasing varies). In fact, it is the only reason that anyone hopes qbits will work. Hence me not being confused.
Unlike what the original poster said, the cat is not already dead when you open the box. That is the whole point of the experiment. The cat is neither alive nor dead until the point in time in which you look, at which point it has already been alive/dead all along.
This principle is the one that drives the quantum computing research. The idea is that you create 512 qbits signifying a number. Since they are in their base form, they each can be either 1 or zero, which means that they are, potentially, all 2^512 possible numbers. You then pass them through a series of filters that, essentially, force them to multiply with another set of 512 qbits and form a known result. Only then do you check what each of the qbits is. You have just factored a 1024 bit integer in zero time by letting quantum mechanics test all possible combination concurrently.
Shachar
Re:Equivalent of peeking without killing it ?! (Score:5, Insightful)
It's 50/50. In one interpretation of quantum mechanics that means that the cat exists in a combination of both states prior to observing it. Observing it causes one or the other of the states to prevail.
It is the only interpretation that I am aware of (though its precise phrasing varies).
There are many other interpretations. The one where it exists in a combination of the possible states is the Copenhagen interpretation.
Another popular one is the many words interpretation. Instead of the cat being in a combination of the possible states, there are multiple universes with each universe containing a different possible history (dies at T=1, dies at T=2, still alive, etc.) and there is a different version of the observer in each universe coming to a conclusion based on which universe he's in.
In the relational interpretation observer 1 could take a peek, and know the cat is dead, while for observer 2, who hasn't peeked, the cat is still in both states.
In the ensemble interpretation the cat is definitely either alive or dead, you just don't know which before making the observation. The probability distribution does not apply to a single cat, but rather to an ensemble of cats. Repeat the experiment 1000 times and you'll get about 500 alive and 500 dead.
Unlike what the original poster said, the cat is not already dead when you open the box. That is the whole point of the experiment. The cat is neither alive nor dead until the point in time in which you look, at which point it has already been alive/dead all along.
That interpretation is different from "the only interpretation [you] are aware of." As I said above the interpretation Schrodinger was discussing has the cat in a combination of both states. Not that it's not in "neither" state. It's in a combination of them. The AC above was pointing out that you might not be keeping the cat alive while peeking. You might be peeking while keeping the cat dead. Or as the article rather than the headline actually says, you get to peek and keep it in the superposition without collapsing it.
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These interpretations all are similar in their measurable outcomes. That's why we have these interpretations instead of focusing in on one of them.
The many worlds postulate, for instance, doesn't split the universe into many until the observation is made. So the cat is in a multi-state until that point in time. In all the interpretations, there is a multi-state until the measurement is made and then something happens, depending on the interpretation.
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Does this method of observing really change anything? To me, it doesn't unless they can actually measure it, find it dead, measure again, the find it alive. If the observation is still fixing the state, in what way does this help? I will add here that I an not a quantum physicist,I did not RTFA, and it's 06:00. (That sounds like the SlashDot equivalent of that line towards the end of the "Blues Brothers").
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Re:BOO BEAR of peeking without killing it ?! (Score:2, Funny)
""The probability distribution does not apply to a single cat, but rather to an ensemble of cats. Repeat the experiment 1000 times and you'll get about 500 alive and 500 dead.""
The whole point of these experiments is to front the whimsical idea of someone, somewhere performing them 1000 times. "What did you do today, honey?" "Number 782." "Alive or dead?" "I'd rather not discuss it." "Oh really--does that mean this cat is in an undetermined state?" "Yeah--for you, now shut up and pass the peas."
Or you go
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Ma
Re:Equivalent of peeking without killing it ?! (Score:4, Informative)
No, you don't get to peek at the cat's state. You can peek at some other property, like how fast it's transitioning between (quantum) states, but you can't see the cat's state.
To use the analogy of the thought experiment, maybe you could peek in the box and determine whether there is a cat in the box at all, or what colour it is, but if you look long enough to determine whether the cat is alive or dead then you'll destroy the superposition.
Re:Equivalent of peeking without killing it ?! (Score:5, Interesting)
It is the only interpretation that I am aware of (though its precise phrasing varies).
That is the Copenhagen interpretation. There are several others: In the many-world interpretation, there are universe in which the cat is alive, and universes in which the cat is dead. Until you open the peek, you can interact with both. Ones you have peeked, the versions of you in the universe where the cat is dead and the versions of you in the universe where the cat is alive diverges, and cannot interact anymore (roughly). Then there is the de Borglie-Bohm [wikipedia.org] interpretation, where the cat is either dead or alive (particles have a definite, deterministic position), but until you have observed it, you can only interact with the wavefunction, which is the same for dead and alive cats (I think, but I might have horribly misunderstood it). In fact, there a quite a lot different interpretations of quantum mechanics [wikipedia.org]
In fact, it is the only reason that anyone hopes qbits will work.
Qubits works because of quantum mechanics, that is, because the equations are as they are. That have nothing to do with the interpretation, which is how we understand the equations. Interpretations are not scientific, as they make exactly the same predictions as the underlying model, but are more complex. They are not really needed, but the human mind doesn't like thinking in equations, it prefers to have something that behave like something physical, so we like having them.
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Qubits works because of quantum mechanics, that is, because the equations are as they are. That have nothing to do with the interpretation, which is how we understand the equations. Interpretations are not scientific, as they make exactly the same predictions as the underlying model, but are more complex. They are not really needed, but the human mind doesn't like thinking in equations, it prefers to have something that behave like something physical, so we like having them.
The equations are derived through observation of physical reality. The equations are a construct of our minds that allow recognized patterns to provide predictions of physical reality. The interpretations are arguably more accurate than the equation, as they can possibly identify conditions the math has yet to be 'adjusted' to account for. To discount the source of these equations - our perceptions of the universe - is foolish.
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That doesn't make sense. The equations of quantum mechanics describe the world, they don't create it (otherwise the world would only be a century old). We've found equations that work, but just like any equations they only tell us what's happening, not why. Newton's or Einstein's equations or the ideal gas law are no different.
Re:Equivalent of peeking without killing it ?! (Score:4, Insightful)
Not exactly. A cat in such a situation would of course be dead or alive, regardless of whether you observe it or not. You may not know *whether* the cat is alive or dead, but you know *that* the cat is alive or dead. The measurement of the state to choose whether or not to kill the cat would in itself collapse the waveform.
Schroedinger developed the thought experiment to describe what he considered the absurdity of the Copenhagen interpretation of quantum mechanics. It's not meant to be taken as literally as it is tended to be.
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Not exactly. A cat in such a situation would of course be dead or alive, regardless of whether you observe it or not. You may not know *whether* the cat is alive or dead, but you know *that* the cat is alive or dead.
The experiment doesn't work, so you are right. But had the experiment worked, then that claim would be incorrect. The point in time in which the universe decides whether the cat died or not is when we test it, not before. If we never test the cat, it is neither alive nor dead.
The measurement of the state to choose whether or not to kill the cat would in itself collapse the waveform.
Exactly. It is uncollapsed before the measurement.
Schroedinger developed the thought experiment to describe what he considered the absurdity of the Copenhagen interpretation of quantum mechanics. It's not meant to be taken as literally as it is tended to be.
But that interpretation prevailed. That is the whole point of ESR. It is not possible to extend a wavelength function, uncollapsed, to the size of a cat, but when actual atoms are invol
Re:Equivalent of peeking without killing it ?! (Score:4, Informative)
What would be wrong about it ?
You put a coin in a box, shake the box. surely, it is either head or tails, you just know what it is when you open the box
So why do you think there is such a buzz around the Schrödinger’s cat ?
Precisely because, the experiment is setup so that the cat is not either alive or dead, but in a special state
Schrödinger put together this thought experiment to show how silly the Copenhagen interpretation was (to his eyes)
The experiment is there to say "according to you, the cat is both dead and alive (which we can all agree on is ridiculous)"
Except it's not that simple, and then, there is entanglement and there indeed are "weird mixed states"
Actually it is right but also wrong (Score:2)
Re:Equivalent of peeking without killing it ?! (Score:5, Insightful)
In one interpretation of quantum mechanics that means that the cat exists in a combination of both states prior to observing it.
The only thing in any sort of superposition is the measuring device. The hammer which breaks the beaker of cat poison, the beaker breaking and the cat dieing are not part of the superposition. They are all separate events but whatever it all sounds much better if you make mystical claims.
Observing it causes one or the other of the states to prevail.
No it is "disturbing" not "observing" ... just more unecessary mysticism to make understanding basic ideas seem more difficult than they actually are.
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Untrue, and in fact the WHOLE POINT OF THIS ARTICLE is actually to describe why the 'classic' interpretation of the Uncertainty Principle doesn't work, because it doesn't explain how you can perform certain types of measurements on a set of entangled quantum states. This would not be possible if the "changing the state" interpretation was correct. In fact what is being established here is a more exact and in some sense looser type of Uncertainty Principle. Much like Newtonian Mechanics at the limit are indi
Re:Equivalent of peeking without killing it ?! (Score:5, Interesting)
Meh, it's already been done experimentally
Have a look at the Quantum Zeno Effect which is both one of the scariest and most awesome pieces of experimental quantum physics around. Just in case your Google is broken, the experiment stops the random decay of unstable particles by continually measuring their state. Since the cat is just an allegory for these sorts of particles, the experiment has already been done - yes you can prevent a random (quantum) event by taking continuous measurements.
You don't need this thought experiment any more - as *real* physics cruised past these mind games decades ago.
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Geordi La Forge
Re:Equivalent of peeking without killing it ?! (Score:4, Interesting)
But weakly observing it can have value. It would be possible, for instance, to determine whether there is a cat in the box at the moment (perhaps by weighing the box and comparing the finding with a predetermined minimum-weight-of-cat value). This is important because a cat that is not observed in any way may or may not be in any particular place. Anyone who has ever lived with a cat knows this. People who have never been owned by a cat may be incapable of understanding this, and probably should not look for a career as a quantum mechanic.
But that explanation might be too subtle for classical physicists (who likely do not much like cats, ever since Schrödinger soured them on the cute little beasties). So for them the dilemma can be stated in a more gross fashion: how can you even know whether a cat in the box is a part of the device you are trying to build unless you at least look at whether a box is or is not present? It would seem that some degree of weak observation is indeed necessary if anything is to be done.
The underlying problem is of course that quantum mechanics sits in the intersection of physics and semantics. It is not only the case that classical physics is unable to handle what is happening at the quantum level. It is also the case that as a product of this Universe, the human brain is basically incapable of understanding quantum level events. There's something happening here, but what it is ain't exactly clear... and never will be. So sayeth the Copenhagen convention.
I don't expect anyone on Slashdot to accept this on face value. But I do have a citation: check this out. [straightdope.com] One of the more obvious implications is that if you do not have a sense of humor, then becoming a quantum mechanic is not a good career choice for you.
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"50/50" is probability, you need more than one experiment to decide the ratios of the two different states. The problem is, once you have made, say 1000 experiments you have really just moved 1000 steps along a path; there are other paths you could have ended up on. So maybe you come to exactly 50/50 as the ratio, but somewhere out there in the multiverse there is a world where the 1000 experiments led to a 70/30 ratio instead. You just cannot observe it because you diverged at some point: You are not there
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I think you missed the whole point of the thought experiment. No, the cat is decidedly not already dead when you peeked. It is the moment of your peeking that picks a state for the cat.
The worst ever "thought experiment" by far is Schrodinger's cat. To say a living cat was ever in a superposition of alive or dead is wrong and stupid. These words only confuse people unecessarily.
No cat was never a participant in any coherent quantum system only the measuring device which **triggers** death of the cat had anything to do with the quantum system.
Asking if a tree still falls in the forest if nobody sees it is about as instructive as the cat in the box analogy.
Which, of course, means that the summary is meaningless. I'll go read TFA, and, more likely, then consult with a Physics Phd I know to try and make (relative) sense of this discovery.
Nothing at all has been "discov
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The cat is alive or dead and not ever in a state of superposition.
The example was (I hope intentionally) chosen to illustrate how poorly our macro world and macro thinking fail at the quantum level.
If you have any doubt of this and are romantically tied to the "alive and dead" cat, consider this: The cat is capable of making an observation. It is a complex collection of moving parts. If the parts stop moving, that is an observation.
It may be the case that quantum states on small particles do not have any
Failing to understand the concept of system (Score:2)
The inside of the box is a system, it is isolated from the outside of the box. It is irrelevant that parts of the system inside the box can measure other parts. Quantum superposition is a relative state, as far as the insides of the box are concerned there is no superposition, but to the observers OUTSIDE, until they exchange information with the inside, the superposition exists. Moreover these superpositions are NOT just artifacts of insufficient knowledge. Bell effectively proved this back in the 60's, th
Re:Equivalent of peeking without killing it ?! (Score:5, Informative)
This is the equivalent of weighing the box. By not opening the box you don't collapse the wave function. Instead you measure some other property that is independent of the wave function. It is nothing like peeking in the box, nor does it gain any information from the wave function.
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But weighing the box won't tell you anything (no, a cat's soul does NOT weigh 21 grams). I think it's more the equivalent of smelling the box.
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No. You cannot measure whether the cat is alive without causing a determination of that very question. You can measure other things, though.
I should point out that the cat analogy is not a very good one, and TFA chose it only to make the article more appealing.
Shachar
Re:Equivalent of peeking without killing it ?! (Score:4, Interesting)
I always wondered why the cat didn't qualify as an observer to begin with.
This is the justification for the relational... (Score:3)
interpretation. In that interpretation there is no need to consider the question of 'observers'. Quantum states are relative, and to say that a waveform has 'collapsed' is just a statement about its relationship with certain other parts of the system. Thus it is irrelevant that the cat could 'observe itself', this is surely true, but then it is only alive or dead in relationship to itself (and the rest of the inside of the box). To observers outside the box it is in a superposition because that is how they
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My understanding anyway.
'quantum' as a marketing buzzword_and 'no' (Score:2)
Excellent question...I have thought much about it, as it used to be my job. Two electrons entangled in a true quantum state would be a perfect communication device...any change to the state of one would instantly change the other in the same way regardless of distance
In that **truly quantum** scenario, we would indeed have quantum signal transmission at a rate of 1/1...faster than the speed of light...instant over any distance...
That's **kind of** a big deal...Einstein called it "Spooky Action at a Distance
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Two electrons entangled in a true quantum state would be a perfect communication device...any change to the state of one would instantly change the other in the same way regardless of distance
That's mumbo jumbo and simply untrue. Both have a state, peeking at one just tells you what the other is it doesn't change any state.
Quantum "instant" communication is impossible and will therefore never happen.
Look it up & get back w/ me (Score:3)
No, you're just wrong...and you actually agreed with me when you said, "...will never happen."
See, you really need to read up on 'Action at a Distance' because it is *exactly* the phenomenon you, I, and particle physics thinks will not and cannot happen...
Yet, Einstein himself identified it as predicted in his models....seriously look it up
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RightSaidFred chose his words carelessly. You are all correct but talking about different things.
Yes, there is "communication" in the sense of "spooky action at a distance". No, you cannot transmit classical information that way.
Except what we do know is that currently you're simply forbidden from transmitting information faster then light this way. There's nothing that would forbid "spooky action at a distance" from transmitting information at or below light speed, provided some means could be found to allow it to do that.
This would still be a huge discovery in a world where electromagnetic spectrum is highly limited and interceptible, and it's why I find these weak measurement experiments so interesting. You could imagine for exa
Re:first post ! (Score:5, Funny)
Does anyone here RTFA?
Of course! It's about scientists no longer using sledgehammers to check for the existence of cats in a box. Instead they shine a torch inside. Quite obvious really!
Re:first post ! (Score:5, Funny)
Re:first post ! (Score:5, Informative)
Does anyone here RTFA?
Yes, I did. The summary quotes this part line by line: "physicists have managed to probe a delicate quantum state without destroying it – the equivalent of taking a peek at Schrodinger's metaphorical cat without killing it."
This shows a fundamental misunderstanding of the cat experiment, in that the author is assuming that by opening the box the cat gets killed. When in fact the cat can be considered both alive AND dead while the box is unopened, and if you open it it might very well be alive and not dead. Thus it would be equally accurate (or inaccurate, rather) to say "the equivalent of taking a peek at Schrodinger's metaphorical cat without making it LIVE."
And to be even more nitpicky, it does alter the quantum state- it changes the oscillation but does not destroy the superposition. They also have (simply put) found a way to return the oscillation to the pre-observation state within a relatively small timeframe.
So yes, the parent's "???" was justified as the use of the analogy was horrible incorrect.
Re:first post ! (Score:5, Interesting)
This shows a fundamental misunderstanding of the cat experiment, in that the author is assuming that by opening the box the cat gets killed. When in fact the cat can be considered both alive AND dead while the box is unopened, and if you open it it might very well be alive and not dead. Thus it would be equally accurate (or inaccurate, rather) to say "the equivalent of taking a peek at Schrodinger's metaphorical cat without making it LIVE.
I'm not a quantum physicist but If I understand Schrödinger's experiment correctly (feel free to reeducate me), the cat is both alive and dead until you open the box and 'fix' it's state. Until you observe the cat all you can say is that the closer you get to an hour (the radioctive matierial decays one atom per hour) the more likely it is that the cat is dead. So have these scientists managed to observe Schrödinger's cat in it's dual live/dead 'flux' state?
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So have these scientists managed to observe Schrödinger's cat in it's dual live/dead 'flux' state?
They must work for the Umbrella Corporation.
Re:first post ! (Score:4, Interesting)
The Schrödinger's cat is just great marketing for a very straightforward statement. The cat is alive (cat = 1) in 50% of the worlds, the cat is dead (cat = 0) in 50% of the worlds, but you don't know in which world you are until you look at the cat (a.k.a. "collapsing the space of probabilities", big marketing words for a straightforward concept). Schrödinger's merely says that the cat's expected value [wikipedia.org] is: 0.5 * 1 + 0.5 * 0 = 0.5 (but this is a statistics mean, doesn't imply that the cat is both alive and death, just like families never have 1 kid and a half)
The correct way to say it, is that schrödinger's cat is a projection in 3D space of a 4D space problem, where the 4th dimension is the set of "alternate scenarios", and the cat's value at a certain position, is its expected value in that position (a "fuzzy variable").
While you can't get worthwhile info from studying a single cat system without "opening the box", you can discover a lot from a system with many cats; for examples, take a look at nonograms [wikipedia.org].
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Your scenario presumes the cat is alive *or* dead.
I thought this too for a long time, it's only since I recently started reading more on quantum mechanics and the truly baffling experiments that have been done, that I started to understand (or is that, started to confuse) more. In fact, the metaphorical cat is both dead and alive at the same time. It is not in an unknow-but-determined state already. Observing it does not show that it was already dead or already alive. Observing it makes it fall into one of
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That misses the point too though.
The original point of the Schrodinger's cat thought experiment was to highlight an absurdity of quantum mechanics: that if we chained enough causality to a quantum state, the mathematics showed that we ended up with conclusions like a living organism being both alive and dead at the same time (and then as time goes on, both alive and hungry, and dead and decaying, at the same time).
The obvious problem of this becomes more apparent when you consider the proposition that the c
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Yes, but if that happens in a locked and windowless room, to observers outside of the room the entire room plus physicist is still in a super-position of alive and dead until they (or the physicist!) open the door to check. For someone outside the building the system of observers outside and the room are in a superposition until they check. See Wigner's friend [wikipedia.org].
"One atom per hour" (Score:4, Informative)
My dog suggests that this should be tested with a very large number of cats, and a big lump of polonium in each box.
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Not entirely random
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You misunderstand: the statement "Radioactive decay is random" means that "the time between each individual decay event is random." It does not mean "there are no factors that can influence the overall rate of decay."
Re:first post ! (Score:5, Funny)
The cat can be in three states: alive, dead and bloody furious.
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The true state of the cat is that it is not dead yet.
It is not alive in any functional way since like a good cubicle minion it is not interacting with anything outside of its box. And sooner or later it will be dead, for that is the eventual fate of all cats and minions. But since it is possible that the box may be opened somehow before the inevitable death, even though it is not functionally living at the moment we cannot say it is truly dead yet.
There is an equivalent situation in USA Presidential polit
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So it is more like they are checking the cat's box tor signs that the cat is still alive?
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it is more like they are measuring the color of the cat's fur, but don't know if it is alive or dead.
and there seems to be a another consequence of this experiment, if the superposition state is collapsing, they are able to nudge it back into a superposition.
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because then you wouldn't get zombie cats.