Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Topgun on October 26, 2010, 09:19:16 pm
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I am starting to really, really like MW1 interpretation of quantum mechanics, but it has one issue that just keeps bugging me.
It can't be falsified, it also explains things too easily. Like why the universe is almost entirely made up of matter. one solution that MW1 provides is that we can't observe a universe made of equal parts matter and antimatter because then we wouldn't be alive to observe such a universe.
That's too easy.
Now I personally don't care too much if something can be falseified or not but still...
What do you guys think?
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Am I the only one who thought MW1 = Call of Duty 4: Modern Warfare? :nervous:
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Am I the only one who thought MW1 = Call of Duty 4: Modern Warfare? :nervous:
Nope. :p
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That's basically the issue with many worlds - it's a nice fantasy.
It also seems to clash with basic cosmology for me. Depending on how you interpret 'universe'.
Oh and it's wildly overinterpreted as applying at the macroscopic level. Flipping a coin will not split the universe. Something like particle decay will.
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Flipping a coin will not split the universe. Something like particle decay will.
Now, I am not very educated in QM, but I disagree here. The coin is made up of subatomic particles and so is everything around the coin that affects how it lands. Maybe, a long time ago, a radioactive isotope decayed a little in such a way that it would affect the coin toss. Basically its a want for a nail scenario. And since you didn't observe the isotope decaying the universe doesn't split until you made the coin toss, essentially observing the isotope decaying.
At least thats how I understand it.
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well, wouldn't the vigintillions of electromagnetic interactions involved in a coin flip each split the universe?
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On a side note it would be really cool if MW was true and that I could communicate with different version of myself. I could flip a coin to determine if I will do homework or not. the version of me that gets heads will not do homework while the version of me that gets tails will do the homework and then send the other me a copy of the answers
I would only need to do homework half the time :)
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Flipping a coin will not split the universe. Something like particle decay will.
Now, I am not very educated in QM, but I disagree here. The coin is made up of subatomic particles and so is everything around the coin that affects how it lands. Maybe, a long time ago, a radioactive isotope decayed a little in such a way that it would affect the coin toss. Basically its a want for a nail scenario. And since you didn't observe the isotope decaying the universe doesn't split until you made the coin toss, essentially observing the isotope decaying.
At least thats how I understand it.
You understand it wrong. You could argue that the universe splits for the behavior of every constituent particle in the coin that behaves in a probabilistic manner when measured, but particles are constantly measuring each other. The coin itself has no meaning whatsoever as an entity. It does not exist at the quantum level. All that exists is a haze of particles, connected by force carriers.
This is my problem with QM. People forget the Q - it applies only at tiny scales, to tiny things. Macro scale entities are meaningless in all but the most extreme cases.
On a side note it would be really cool if MW was true and that I could communicate with different version of myself. I could flip a coin to determine if I will do homework or not. the version of me that gets heads will not do homework while the version of me that gets tails will do the homework and then send the other me a copy of the answers
I would only need to do homework half the time :)
Flipping the coin is not probabilistic. There is no quantum coherence to the system, so waveform collapse cannot occur and MW is an explanation for waveform collapse. That's all it does.
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But there must be a reality that is exactly the same only with the coin toss result flipped, right?
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But there must be a reality that is exactly the same only with the coin toss result flipped, right?
Yes, just as there is a reality where a high-energy cosmic ray with the kinetic energy of a softball strikes you in the head and kills you as you try to flip the coin. Sheer chance guarantees this. But it will not arise as a result of you flipping the coin; it is not the other branch of your universe that budded off a second ago.
You are making the mistake of thinking the branching would have anything to do with macroscopic events. The branches would (probably) occur at the microscopic level, uncountable gazillions of times in every Planck time length, each time a waveform collapsed.
But bear in mind that Many Worlds is an untestable, meaningless explanation for a total handwave. Waveform collapse itself is an ugly kludge forced onto quantum mechanics.
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But bear in mind that Many Worlds is an untestable, meaningless explanation for a total handwave. Waveform collapse itself is an ugly kludge forced onto quantum mechanics.
I wouldn't say it is untestable, if there was a way to force what reality you end up in or if there was a way to communicate with other versions of ourselves, I would call that evidence. but like I said it can't be falsified.
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Now that I actually know what we're talking about here, for anyone who's into animu, I highly recommend the series Noein, which is essentially centered around a macroscopic application of the many-worlds interpretation. It (loosely) uses a number of the more esoteric (read: crazy) quantum interpretations and concepts, but it's evident that the creators did some research beforehand. Fun stuff.
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But bear in mind that Many Worlds is an untestable, meaningless explanation for a total handwave. Waveform collapse itself is an ugly kludge forced onto quantum mechanics.
I wouldn't say it is untestable, if there was a way to force what reality you end up in or if there was a way to communicate with other versions of ourselves, I would call that evidence. but like I said it can't be falsified.
But the scenarios you're postulating are problematic on their own. What do you mean what reality 'you' end up in? You do not exist at the quantum level. You are a haze of bound particles, each of which would be creating a new universe when it underwent waveform collapse. At any given Planck moment the particles that make up your body are undergoing countless such events.
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Am I the only one who thought MW1 = Call of Duty 4: Modern Warfare? :nervous:
Nope, but I thought it meant Mechwarrior
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does a carbon-dioxide molecule exist at the quantum level?
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Am I the only one who thought MW1 = Call of Duty 4: Modern Warfare? :nervous:
Nope, but I thought it meant Mechwarrior
+1
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does a carbon-dioxide molecule exist at the quantum level?
I dislike people trying to label one size/class of object as existing at the quantum level or not. Quantum mechanics isn't like a form of physics that only applies to one thing. Rather, it applies everywhere, much like special relativity does. Just as you can apply special relativity to every day life and get back to newton's laws, you can also apply quantum mechanics to large objects and still get the correct answers.
Example: Try describing something big, like the moon, with QM and you'll find that the moon can only exist in certain allowable orbits. But you'll find that the difference from one allowable orbit to the next is smaller than the width of a proton. Much too small to be worth worrying about.
So to answer your question, sure, the CO2 molecule "exists at the quantum level", but it's still (mostly, I think) describable through classical mechanics. But if you want to look at the elementary particles within the atoms of that molecule though, then classical physics will not work anymore.
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does a carbon-dioxide molecule exist at the quantum level?
I dislike people trying to label one size/class of object as existing at the quantum level or not. Quantum mechanics isn't like a form of physics that only applies to one thing. Rather, it applies everywhere, much like special relativity does. Just as you can apply special relativity to every day life and get back to newton's laws, you can also apply quantum mechanics to large objects and still get the correct answers.
Example: Try describing something big, like the moon, with QM and you'll find that the moon can only exist in certain allowable orbits. But you'll find that the difference from one allowable orbit to the next is smaller than the width of a proton. Much too small to be worth worrying about.
So to answer your question, sure, the CO2 molecule "exists at the quantum level", but it's still (mostly, I think) describable through classical mechanics. But if you want to look at the elementary particles within the atoms of that molecule though, then classical physics will not work anymore.
*sigh*
The entire point of waveform collapse is a kludge to make QM merge into real-world classical/relativistic behavior.
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To reiterate, general relativity and quantum mechanics cannot both be right.
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To reiterate, general relativity and quantum mechanics cannot both be right.
Sort of. The problem you hit is a divide by zero error when you try to combine the two. But they can both be 'right' in the sense that they are both aspects of a fundamental theory of everything which resolves the problem - in the same way Newtonian mechanics are still 'right' in the scope that Newtonian mechanics generally works in, i.e. low velocities and small masses.
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Am I the only one who thought MW1 = Call of Duty 4: Modern Warfare? :nervous:
I thought it was that too. :(
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This is relevant.
(http://dresdencodak.com/comics/2006-02-13-trouble_in_memphis.jpg)
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argh kimiko is so hot
But see my problem with that **** (and with the Copenhagen interpretation, and with any interpretation that requires a conscious observer) is that particles are constantly 'observing' each other. The system as a whole can never be isolated enough to be coherent because even if the cat is inside the box all the quanta that make it up are getting all busy with each other.
Plus saying that a human is a 'conscious observer' and a cat isn't invokes dualism and that ain't science honey.
and yes i know the schrodinger's box is a metaphor buuut
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argh kimiko is so hot
But see my problem with that **** (and with the Copenhagen interpretation, and with any interpretation that requires a conscious observer) is that particles are constantly 'observing' each other. The system as a whole can never be isolated enough to be coherent because even if the cat is inside the box all the quanta that make it up are getting all busy with each other.
Plus saying that a human is a 'conscious observer' and a cat isn't invokes dualism and that ain't science honey.
and yes i know the schrodinger's box is a metaphor buuut
Unless there can only be one observer for every universe but thats metaphysics territory.
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argh kimiko is so hot
But see my problem with that **** (and with the Copenhagen interpretation, and with any interpretation that requires a conscious observer) is that particles are constantly 'observing' each other. The system as a whole can never be isolated enough to be coherent because even if the cat is inside the box all the quanta that make it up are getting all busy with each other.
Plus saying that a human is a 'conscious observer' and a cat isn't invokes dualism and that ain't science honey.
and yes i know the schrodinger's box is a metaphor buuut
Unless there can only be one observer for every universe but thats metaphysics territory.
Yes, yes it is. And it's what I really dislike about discussing QM without using math, because that's basically just religion.
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or the central plot point of Noein...
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The universe is just full of weird ****
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The universe is just full of weird ****
Yes, but it is full of mathematically defined weird ****, and the definition of 'observer' you are using is not one of them.
Conscious beings are not observers.
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what is the mathematical definition of "observer"?
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what is the mathematical definition of "observer"?
From the new-mostly-abandoned Copenhagen interpretation, an explanation that it's simply a placeholder for an outside system interacting with the quantum state, whether a human being or a billiard ball (in fact it's the act of interaction that's important, not the interactor):
Of course the introduction of the observer must not be misunderstood to imply that some kind of subjective features are to be brought into the description of nature. The observer has, rather, only the function of registering decisions, i.e., processes in space and time, and it does not matter whether the observer is an apparatus or a human being; but the registration, i.e., the transition from the "possible" to the "actual," is absolutely necessary here and cannot be omitted from the interpretation of quantum theory.
—Heisenberg, Physics and Philosophy, p. 137
In modern QM the act of observation is no longer considered to be of any importance since the 'observer' - whether human or any other system - is also a quantum system and what results is simply a vast entangled quantum system.
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Am I the only one who thought MW1 = Call of Duty 4: Modern Warfare? :nervous:
I thought it was that too. :(
Add one to that....
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an outside system interacting with the quantum state, whether a human being or a billiard ball (in fact it's the act of interaction that's important, not the interactor):
ok, so could an "object" (anything consisting of more than one molecule) observe it's self? what differentiates the observer from the observed? how do we know we are not in a super-state and will only have our wave functions collapse when some scientist in France takes a measurement of some subatomic particle which therefore interacts with his instrument which then interacts with him and his lab which then interacts with the planet which then interacts with everything on the planet?
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an outside system interacting with the quantum state, whether a human being or a billiard ball (in fact it's the act of interaction that's important, not the interactor):
ok, so could an "object" (anything consisting of more than one molecule) observe it's self? what differentiates the observer from the observed? how do we know we are not in a super-state and will only have our wave functions collapse when some scientist in France takes a measurement of some subatomic particle which therefore interacts with his instrument which then interacts with him and his lab which then interacts with the planet which then interacts with everything on the planet?
Nobody knows, because the actual, elegant mathematical part of QM doesn't include any kind of provision for waveforms to collapse; that's a feature tacked on by necessity in a kind of hackish way, and nobody really understands it. This is why multiple different interpretations (Copenhagen, many-worlds, instrumentalist, the awful awful awful consciousness causes collapse) exist.
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So why is the Copenhagen interpretation of Quantum Mechanics "mostly abandoned"? What problems does it suffer from?
I'm currently taking an introductory course in Quantum Mechanics so much of this stuff is still rather new to me.
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So why is the Copenhagen interpretation of Quantum Mechanics "mostly abandoned"? What problems does it suffer from?
I'm currently taking an introductory course in Quantum Mechanics so much of this stuff is still rather new to me.
Well TBH I'm not sure myself. I've read it's fallen from primacy. It may be that physicists have simply gone back to the 'shut up and calculate' instrumentalist approach, which makes no interpretation at all.
The problem with all the interpretations is that so far they cannot be distinguished testably. It's not even clear what they mean.
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So if I understand correctly, it sounds like it's not so much that the interpretation is "wrong" as it is that it's not a good scientific practice to be looking at these quantum mechanical principles in a non-mathematical way in the first place?
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So if I understand correctly, it sounds like it's not so much that the interpretation is "wrong" as it is that it's not a good scientific practice to be looking at these quantum mechanical principles in a non-mathematical way in the first place?
It's...well, to my understanding, basically the question of which interpretation of QM you endorse right now is one of hunches and belief, rather than evidence.