Slashdot Mirror
Study Says Quantum Wavefunction Is a Real Physical Object
cekerr writes with this excerpt from an article in Nature
"The wavefunction is a real physical object after all, say researchers. ... the new paper, by a trio of physicists led by Matthew Pusey at Imperial College London, presents a theorem showing that if a quantum wavefunction were purely a statistical tool, then even quantum states that are unconnected across space and time would be able to communicate with each other. As that seems very unlikely to be true, the researchers conclude that the wavefunction must be physically real after all. David Wallace, a philosopher of physics at the University of Oxford, UK, says that the theorem is the most important result in the foundations of quantum mechanics that he has seen in his 15-year professional career. 'This strips away obscurity and shows you can't have an interpretation of a quantum state as probabilistic,' he says."
One of the stumbling blocks for learning this stuff at school was the people were hung up on the idea of "this-space", "that-space". It was a revelation to me that when they said "probability space" it was only a space in the mathematical sense (ie, something with N dimensions that could be graphed if N were not too large).
The way I saw it, people were prejudiced to believe that these were real spaces, the prejudice being that physics is strange at that level, thus there must be strange bizarre types of space. Nope. They were just things with N numerical characteristics.
Now you're telling me there really are strange spaces? That sucks.
"Abstract objects" or "mathematical objects" don't exist in general, so this suggestion is rather plausible. Of course, the reality of the wave function had been proposed before, but new arguments are sorely needed in philosophy of quantum mechanics.
--exa--
is that assault?
I swear they give me mod points to shut me up.
It's not ridiculous at all, it's just counterintuitive. But then, intuition about such things is difficult at best.
That there is uncertainty in the amplitude of the wave function too ?
Nullius in verba
This is what they have proven:
If a quantum wavefunction is purely a statistical tool, then quantum states that are unconnected across space and time are able to communicate with each other.
The rest is speculation.
IMO one observer's wavefunction is the other observer's statistical tool, where an observer is any ensemble of particles.
By the way, the wikipedia article on Bell's inquality stated something similar years ago.
Hey don't blame me, IANAB
Yes yes... Some amazing American innovation done at the ... Imperial college of... London?
They mean London, Arkansas, right?
I don't remember covering 'proof by claiming that something is unlikely' in my Physics degree.
Wasn't this hinted at by those oil-droplet-on-vibrating-medium experiments that partially reproduced the wave/particle duality?
dare step on my wavefunction, mister! Or I'll have to send my engevectors at you!
Where is that guy who'd die defending what I had to say when I need him?
Lolz.
And your brain is just a switching device for different states of reality. This sentence branches into a hydra of different endings, including this one (this one) (this other one) (this other one). Maybe everything you imagine is actually image from realities;
THis MaGiC MoMent.
Sorry for this freaky post-- this version of me can't help but do what it does.
watching The Big Bang Theory?
by TheSpoom (715771) Uncaring Linux user here. I have nothing to add to this but please continue. *munches popcorn*
now that's meta
Yawn. Did these guys ever read Prince de Broglie?
http://galileo.phys.virginia.edu/classes/252/Bohr_to_Waves/Bohr_to_Waves.html
http://en.wikipedia.org/wiki/Louis_de_Broglie
A particle is a wave is a particle-wave; all we can say about the universe, is what we can say about the universe; there's no such thing as a "real physical object."
I would bounce this paper as a reviewer. It appears to be a recasting of Bell's Theorem, but it doesn't reference ANY of that work.
What's the difference? What is the difference between something being a "mathematical description of reality" and being real? I mean you can go back and forth between if numbers are real, etc. Have they discovered something "more real" than they previously thought?
Democracy Now! - your daily, uncensored, corporate-free
Nothing unreal exists
That's an uninteresting tautology.
Everything is physically real.
This, on the other hand, is not true. Plenty of things have no physical reality: like abstract concepts. There is no physical quantity of "good" or "evil", for example. There's not even a physical quantity of "red" (not counting the unrelated color charge from QED). There are physical properties that make things red, but "redness" is not by itself physical.
One class of things that is not physically real is probability distributions. They describe information we possess about a real quantities, but the distribution itself is not real. They're common in statistical mechanics as well.
So does this support or refute the contention that reality is made up of a very very large number of universes constantly being created at each quantum step? Isn't that what the Copenhagen interpretation implied?
The universe is made from block transfer computations?
Because if the "wave function" is a real object, then there is no probabilistic nature to quantum shit - it just means we are currently unable to directly measure the "wave function" without "collapsing" it. If it's not probabilistic, all the fuzziness of quantum physics goes away. Schrodinger's cat is dead, Einstein was right when he said God doesn't play dice, entanglement is horse shit, everyone who works with string theory is a moron, etc.
So, if I throw wavefunctions equations at friends is that assult?
No. They'll just give you a funny look and ask what kind of drugs you are on.
"We are just a war away from Amerikastan. When god vs god the undoing of man." Dave Mustaine
This, on the other hand, is not true. Plenty of things have no physical reality: like abstract concepts.
Nope, the concept is physical real. Its a collection of organized molecules stored in various places in the universe which we interpret into thoughts. Those thoughts are the results of chemical reactions in the brain ... all very real things.
Just because it isn't a specific object you can grab without killing yourself doesn't make it any less real. You're trying to define it out of existence, which is a logical impossibility. It exists because you define it, Ergo Cognito Sum. There is a physical item backing your existence just like there are physical objects backing abstract concepts. Those physical objects just also happen to be part of your mind.
Is your consciousness not real?
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
An instance of considering an abstract concept -- which is what the collection of molecule is -- and the concept itself are different.
It's like people on Slashdot don't even know basic philosophy. I suppose that would explain why so many people thought The Matrix was interesting.
Oh grow up. This kind of bullshit philosophy drives me nuts. Just because the idea is stored somewhere in a physical arrangement only makes that specific instance of the idea as pertains to a human being able to recall it real. It does not make the subject of the thought real, which is what we're talking about. Nobody is denying thoughts manifest in physical ways, but just because I can think about a unicorn doesn't make the unicorn itself physically real, just the thought of it is physically real. If you don't understand the difference, you think too highly of your own intelligence.
If I can just reach out with my words and touch a butthole, just one, it will all be worth it.
I think you fail to understand what the term "abstract" means. My mind's conception of a circle may have a physical manifestation in my brain, but my mind's conception of that circle is not the abstract circle.
Before you start quoting Descartes, perhaps you need to revisit your Plato.
----
Not to be confused with Col.
I think the other possibility is just as fascinating, and possibly more impactful. The idea that all quantum states are related, even when not entangled. I'm certainly not a quantum physicist, but that seems like it would open amazing possibilities.
Ladies and gentlemen please look to the to the AC above. Observe the unrelated statements, the illogical statements, and the excessive long list of names being laid out for no particular reason, in a very non-slashdotesque manner.
Gentlemen, and ladies, we have ourselves an employee of the misinformation industry.
Gotta love quantum news posts: meaningless and meaningful at the same time, like a newspaper written by Schroedinger's Cat.
Copernican theory was picked up fairly quickly because it offered a simpler view of the cosmos. Astronomers bought into it largely because of its simplicity -- in effect, following Occam's Razor. It took until the early twentieth century for Einstein to say "you're all a bunch of doofuses: Ptolemaic theory is just as valid as Copernican, it all depends on your frame of reference." Thanks to relativity we now know beyond any shadow of a doubt that Ptolemaic epicycles are equally valid: they're just more complex. There is no privileged frame of reference. It is as true to say the Earth circles the Sun as it is to say the Sun circles the Earth -- it's just that the equations are neater in one frame of reference, not that they are correct. This bears repeating: according to special relativity, there are no privileged frames of reference.
Naively applying Occam's Razor to the question leads people to a false sense of certainty: they tend to think, "I've applied Occam's Razor, therefore I am likely choosing the better answer," without ever thinking, "did I formulate the question correctly in the first place?"
Don't get me wrong, I like Occam's Razor. But when people use Copernican-versus-Ptolemaic theories as an example of Occam's success, well... that tells me a quick lesson needs to be given on how Occam's Razor utterly fails in that case.
Sheldon Cooper is going to be pissed.....
http://motls.blogspot.com/2011/11/nature-hypes-anti-qm-crackpot-paper-by.html
"Whatever way you choose to read the text [of the paper by Pusey et al], it makes no sense whatsoever. How they suddenly jump to the conclusion that there is a problem with the probabilistic meaning of the wave function remains completely mysterious."
I always suspected he would end up working under Pusey.
SJW: Someone who has run out of real oppression, and has to fake it.
To every physicist it is immediately clear that this paper is complete nonsense. I don't want to waste time disproving it here and will simply refer you to this explanation.
Wave function is a real object? You gotta be kidding. Next thing you will say "corporations are people". Oh! wait..
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
So, what I'm not getting is this: If a waveform is a real physical object and not just a conceptual statistical function, what is the physical nature of this object? Is it a half-dead Schodinger's Cat? Or is it a world where the Cat lived superimposed on a world where it died? Is it (gulp) both?
The result of the wavefunction is a correlated outcome within everything embarked within it.
It should be obvious this behavior can not be explained by an abstract statstical statement as it would not include correlated outcomes.
I have no idea what if anything useful TFA is trying to say.
Not quite; the paper hinges on having in existence a lambda that is a complete physical state that is the superset of the various properties defined by the wavefunction. That seems, at first, like a hidden-variable theory, which would come back to your statement. However, all they are saying is that the statistical interpretation allows for a generator of a pure state may yield a physical state that can "collapse" into the other state.
I am not very happy with at least the first argument (have not worked my way through the second) since the initial assumption breaks the preparation, as I see it, because having lamba be compatible with either of two unequal, pure, non-orthagonal states implies that the only part of lambda that can yield independent measurements is the set of properties not in the intersection of |phi_0> and |phi_1>. That would seem to imply that lambda cannot be generated by either a generator of pure state |phi_0> or |phi_1>, unless I am missing something important.
I could go back a couple of centuries and make the same flawed logical argument - "as it is unlikely that the earth moves, therefore it MUST be the center of the universe."
The funniest thing is that this paper is coming out in the midst of the discussion of faster-than-light neutrinos. According to the interpretation presented in the article blurb at top, FTL neutrinos should be forbidden. If they actually exist, however, then that means that the quantum wave function really is a stastical thing and not a physical thing.
Because if the "wave function" is a real object, then there is no probabilistic nature to quantum shit - it just means we are currently unable to directly measure the "wave function" without "collapsing" it. If it's not probabilistic, all the fuzziness of quantum physics goes away. Schrodinger's cat is dead, Einstein was right when he said God doesn't play dice, entanglement is horse shit, everyone who works with string theory is a moron, etc.
Wrong. (And yes, I am a physicist working in quantum information)
The canonical formalism contains the "collapse" of the wave function on observation, and this collapse is probabilistic. And there are interpretations of quantum mechanics with real wave function and real collapse (e.g. the Ghirardi–Rimini–Weber theory). Now there also exist deterministic interpretations of quantum mechanics which also include the wave function as real object (such as Bohmian mechanics). In other words, the wave function being real is completely independent of the question whether the world is fundamentally deterministic or not.
By the way, the paper does not really prove that the wave function is real. What it proves is that if you assume that there is something like a real state of the quantum system at all (and assuming quantum mechanics is actually right) then that real state must include the full wave function. There are some physicists who claim that quantum systems don't have physical states at all (an idea known as Quantum Bayesianism). That assumption is not refuted by this paper.
And entanglement is a property of wave functions, therefore if wave functions are real, then obviously entanglement is real.
The Tao of math: The numbers you can count are not the real numbers.
Because then wave-particle duality are really just the same thing? I don't know much about this subject, but it seems that we have to rethink light rays... ?
We can measure light as both a wave and a particle. But they are both physical? So is the particle a dot which waves? Or springs back to a dot and out again to a wave?
Who knows...
Here be signatures
In the Nature blurb, there's a bit of discussion at the end that quantum states might all be linked, entangled or not.
In most physics classes, you learn quantum mechanics by calculating the interactions between isolated states. This thought process is natural and useful for certain areas of physics, but you end up worrying about hidden variables and how particles which are essentially in different universes can possibly communicate. This view does not need the wave function to be real, it can just be a statistical tool.
An alternative way of thinking about things is the idea that there are no isolated states (and no measurement apparatus which can exist outside the quantum system). From that point of view, one wave function is sufficient to describe the entire universe, traced back to the big bang. You don't need to worry about spooky action, everything obeys causality just fine assuming the wave function is real. There are some cosmological issues still, and it's not clear such a unified state is possible in an infinite universe.
At least we're starting to all agree wave functions are real and not just a statistical tool.
"Concepts" cannot exist at all without some form of persistence. The persistence relies on physical objects (though I won't limit that to "chemical reactions" nor "in the brain" as per the parent post).
If a civilization develops the concept of boolean algebra, and then that civilization is completely destroyed and all record of the concept of boolean algebra is lost, "boolean algebra" ceases to exist. If another civilization arises and redevelops a concept that is in all respects similar, it is still not the same concept.
One could pretend to be an "outside observer", and compare the two concepts and call them the same concept, but then you have violated to conditions -- you have kept a record of what the concept from the destroyed civilization was, and that record exists in some physical form in order to get it from timespace A to timespace B.
Now it is tempting to say that since concepts like boolean algebra are developed methodically with a set of indisputable rules from axioms that they are "real" without being physical, but that presupposes that even stating the axioms does not rely on physical phenomena.
In other words, "mathematics" is really a verb when you get right down to it.
Someone had to do it.
Stand by to see which theory Schrodinger's cat buries in his litter box.
Have gnu, will travel.
It's like people on Slashdot don't even know basic philosophy. I suppose that would explain why so many people thought The Matrix was interesting.
The Matrix had bullet time, Carrie-Anne Moss, and Kung-Fu fighting. I don't recall philosophy being much more than filler between those things.
I think it's great.
I think the wave function is a physically real object(*), and the randomness is not intrinsic or magically special but comes from thermodynamics and chaos, and, yes, Einstein was right: Copenhagen is a nonsensical load of bollocks.
More specifically that dice are not actually random in an ineffable sense, but their practical use has a sufficiently high Kolmogorov-Sinai entropy rate (roughly average amount of chaos generated per time) that they're random enough. In other words, quantum mechanics is regular physics, not mystical Copenhagen mumbo jumbo. Copenhagen works for computation, but that's because it's a very useful approximation for experimentally relevant circumstances, just like Fermi's "Golden Rules". Einstein was right, at least about the problem. His proposed solutions weren't, but the experimental evidence wasn't available until after he died and obviously he would have changed his mind given new results, because he was a physicist foremost and not a mystical philosopher.
Entanglement and uncertainty principle are not horse shit, because the central mystery of QM, that everything is operating in a Hilbert space still remains.
(*) To me, physically real means "acts as a source term in gravitation". This pretty clearly distinguishes "electrons/protons/photons" from "set of all sets of sets" crap and is as useful as any other description I know. Of course we don't have quantum gravity working yet but when we do it's pretty likely something like the wavefunction will be in there.
The alternative was to treat the wave function as a purely mathematical object, and to interpret it purely in that way.
The difficulty here is what happens when you measure the position/momentum of an object? Does the wave function "collapse" to a point? What happens after you measure? Does it become a wave function again? What?
If the quantum spectral representation or orbitals something real, or is it just a mathematical convention analogous to Fourier series, or decimal digits? Should we see an electron as something like 0.333333333... or 1/3? This study suggests that we should see the wavefunction as we see 1/3, and not as the collection of place value numerals which we see in 0.33333....
May the Maths Be with you!
The persistence relies on physical objects
You are confusing the concept with the implementation. There's the abstract concept of a song. That abstract concept could be implemented as a videoclip, as a set of guitar chords, or in many other ways. But in the end it's the same concept. Different physical implementations, same abstract concept.
"We can measure light as both a wave and a particle. But they are both physical? So is the particle a dot which waves? Or springs back to a dot and out again to a wave?"
The problem is more complicated than that, but it has been solved completely satisfactorily now with the proper application of quantum mechanics to electromagnetic fields, known as quantum optics, and verified experimentally.
Very toughly, light is a quantum mechanical superposition of the electromagnetic modes. A 'wave function of functions', and the 'particles' are the elementary excitations of the modes, meaning there is an operator which can count them and give an integer.
Note that photons, unlike normal matter we otherwise come in contact with (protons + electrons + neutrons) does not have a conservation law. In 99.999% of our interactions, protons/electrons/neutrons are not destroyed or created, but with photons that happens really easily. So the practical experience is very different, though some fundamental properties are similar.
I saw the paper when it originally appeared on the arXiv. They claim to randomly prepare a pure state. This is a contradiction in itself, as von Neumann and others have already shown decades ago that random ensembles of states (or local parts of a globally pure state) have to be described by mixed states. If one uses the proper mathematical concepts, their results vanish immediately.
OS Reviews: Free and Open Source Software
The fact you called MWI "scientifically plausible" should be the first sign you don't have the first clue what you're going on about.
For MWI to be "scientifically plausible" it would have to make predictions which could be confirmed or falsified via experiment. That is, in essence, what science is: the subjecting of ideas to experimental test. (Go ask Zombie Feynman if you don't believe me.)
I've yet to hear any testable predictions MWI makes that would allow us to differentiate it from, say, Copenhagen. Maybe that's changed since I last dove into things (and if it has changed, I hope you'll tell me so), but I kind of doubt it.
David Deutsch is famous for saying that MWI is the only interpretation that gives any kind of sense to quantum computation. And, you know, I'm inclined to agree with him. That doesn't mean MWI is correct, though: it just means that the other interpretations do not satisfactorily explain those phenomena, not that MWI is the only possible interpretation that could give sense to quantum computation.
Also, given Copenhagen was first developed by Werner Heisenberg, it's kind of crazy to claim that Copenhagen is a "superstitious and completely nonsensical" interpretation. If I have to choose between exa on Slashdot being right when he says Copenhagen is superstitious and completely nonsensical, and Zombie Werner Heisenberg being right when he says that exa on Slashdot is misunderstanding Copenhagen, well... I'm going to side with Zombie Werner Heisenberg, you know?
Wrong. Bell's theorem's implication is that there are no local hidden variable theories which can explain quantum mechanics. Non-local hidden variable theories are not excluded by Bell.
The Tao of math: The numbers you can count are not the real numbers.
Those are things that make it entertaining, not interesting. Although I probably should have clarified that people seemed to think the ideas in The Matrix were interesting, when in fact they were simple, rehashed philosophy.
All they proved is that the simple statistical model is inadequate to describe why spooky-action-at-a-distance is not more commonplace.
David Deutsch is famous for saying that MWI is the only interpretation that gives any kind of sense to quantum computation. And, you know, I'm inclined to agree with him.
His understanding of quantum computation is also astoundingly flawed.
I'm sorry have I missed something, what does the term exists mean in this context?
Don't all ideas and mathematical constructs , including dreams exist? If they didn't we would not have words to describe them, because no one would ever have experienced them.
Is there some definition for the word exists that doesn't require recourse to metaphysics for it's definition?
I mean you might say occupies objectively measurable space time , but isn't that a pre-requisite for experimentally derived data?
âoeTolerance applies only to persons, but never to truth. Intolerance applies only to truth, but never to persons.
To make a simple analogy: Say you have two machines named "psi" and "phi" producing badges with numbers from 1 to 10 on it. Now it happens that the "psi" machine only produces even numbers, while the "phi" one only produces multiples of three. Other than that, the number produced by each of the machines is completely random. Now if you know you have a badge from machine "psi", but can't see the number, you still know that it might be a 2, a 4, a 6, an 8 or a 10, but you don't know it. So if you know the badge is from machine "psi", you call the bedge a "psi badge". "psi badge" is now the "quantum state" of your badge system. Similarly, if the "phi" machine produced it, you know that the badge contains one of 3, 6 or 9. You call that a "phi badge". Now the assumed physical state in this picture is the actual number on those badges. If that happens to be the number lambda=6, the badge could have been produced either by the "phi" machine or by the "psi" machine, you cannot tell just from the number on the badge which machine produced it (while e.g. if the badge contains the number 4, you know for sure it wasn't the machine phi because 4 is no multiple of 6).
The Tao of math: The numbers you can count are not the real numbers.
> If a civilization develops the concept of boolean algebra, and then that civilization is completely destroyed and all record of the concept of boolean algebra is lost, "boolean algebra" ceases to exist.
That is mostly correct, but you're forgetting one little fact -- the universe is a giant mind, so nothing is "truely" lost.
> If another civilization arises and redevelops a concept that is in all respects similar, it is still not the same concept. ... 9, and identical '+' processes, the concepts are the same. How they are implemented and thought about, may be very well different, but the concepts themselves are identical.
That may be false; if they come up with the same boolean "laws" then it is the same concept.
i.e.
If two people on either side of the universe come up with the concept of 0,
What a crappy summary and crappy article. The wavefunction is no more a real object than any other mathematical function. The statement: "f(x)=x^2 is a real object" has no valid meaning whatsoever. To even call it a theorem is ridiculous. Likewise goes for the wavefunction. It is a tool to model our "real" world. Some models are exact and precisely describe the "real" world. Other models only work under certain assumptions and/or reference frames.
If you actually read the research paper, the authors consider the question of whether a quantum state is a physical property attached to a system. Said another way, do quantum systems actually exist? Or are they purely theoretical? From the article:
"The statistical view of the quantum state is that it merely encodes an experimenter's information about the properties of a system. We will describe a particular measurement and show that the quantum predictions for this measurement are incompatible with this view."
The gist of it is that they have produced a result (didn't read the whole thing to actually figure out what their result was) which relied mainly on three assumptions:
Since their result is incompatible with the statistical view of quantum states, it must due to one of the assumptions above. They don't actually make the claim that quantum states are physical properties (like length, width, height, mass, etc. are). In fact, they conclude with:
"More radical approaches are careful to avoid associating quantum systems with any physical properties at all. The alternative is to seek physically well motivated reasons why the other two assumptions might fail."
What it proves is that if you assume that there is something like a real state of the quantum system at all (and assuming quantum mechanics is actually right) then that real state must include the full wave function.
I've not dug deeply into the paper yet, but I don't understand their measurement apparatus (I'm an experimentalist but not in this field.) Their various states look to me like perfectly ordinary linear polarization states, so their "00/0+/+0/++" apparatus ought to be some kind of linear polarimeter, like a sequence of polarizing beam-splitters with ones at 45 degrees on the arms of one is vertical/horizontal, probably, ultimately, I guess with a recombining of the beams as in a Mach-Zedner interferometer...
But since there is no (apparent) interaction between the two photons I don't see what they mean by a "joint measurement" in this context. Can you give some insight into what kind of measurement apparatus they are actually talking about in the ideal case that would allow them to make the kind of "joint measurement" their argument depends on?
Blasphemy is a human right. Blasphemophobia kills.
Sure, but so is everybody's. I'd be a very happy man if my successes were half as brilliant as Deutsch's mistakes!
The problem is more complicated than that, but it has been solved completely satisfactorily now with the proper application of quantum mechanics to electromagnetic fields, known as quantum optics, and verified experimentally.
Right, so a photon, which is a light particle, is actually a electromagnetic pocket? And electromagnetism is bound by gravity, which then causes waves? And this soup, as shown with the double slit experiment, results in wave-particle patterns to the observer....
Very toughly, light is a quantum mechanical superposition of the electromagnetic modes.
Either a photon or a wave.
Note that photons, unlike normal matter we otherwise come in contact with (protons + electrons + neutrons) does not have a conservation law.
Because photons are formed by fundamental stuff that is bound by conservation. Same as if Lego bricks are conserved, but the car or crane they resemble is not conserved if the Lego bricks are disconnected?
Am I getting it, or totally not?
Here be signatures
Nothing exists in our minds apart from the information we have been given by our senses or that which is a product of the biological processes of our brain. All thought exists physically within our brain as neurochemical interactions, to say otherwise is to presume that there is some as yet unobserved action that does not depend on physical forces going on inside our heads. You cannot say that a concept, abstract or not, exists entirely divorced from physical reality. To do so would be to assume the existence of a reality (if you could call it that) not related to any known physical process and in no way connected to our own, in which case you might as well be talking about the existence of God.
An instance of considering an abstract concept -- which is what the collection of molecule is -- and the concept itself are different.
"Basic philosophy" is nothing but an ongoing argument between ignorant people over things they know nothing about. For the past three hundred years those people haven't just been ignorant, they've been willfully ignorant. For the past thirty years they haven't just been willfully ignorant, they've been more-or-less criminally ignorant.
Starting from a stone-age conception of the way the world ought to be and armed with nothing but the known-to-be-inadequate-to-comprehend-reality set of "common sense" impressions they have of the world around them, they fail to distinguish between different things, ignore facts that don't conform to their beliefs and then insist that the rest of us are ignorant when our thinking doesn't conform to their ridiculous presumptions.
The very claim you make is a highly contentious one that any genuine student of "basic philosophy" knows has multiple answers depending on which more-or-less criminally ignorant person you ask. Some more-or-less criminally ignorant people will tell you that there are no "abstract concepts" at all. Others--like Plato and Descartes--will tell you some gibberish about "abstract concepts" having a kind of existence that transcends the physical. Of course, asking their opinion on such a question would be like asking, say, an extremely bright high-school student brought up in a deeply religious family and educated by monks who taught only things known before 1600. Why anyone would want to do that is beyond me, but such a student would have precisely as much epistemic authority as Descartes or Plato.
Blasphemy is a human right. Blasphemophobia kills.
Bell's theorem's implication is that their are not "hidden variable" theories that can explain quantum mechanics.
Wrong. Bell's theorem's implication is that there are no local hidden variable theories which can explain quantum mechanics. Non-local hidden variable theories are not excluded by Bell.
I'd even go one further -- it isn't clear what Bell's theorem implies as soon as you make quantum mechanics properly relativistic and time reversible within a closed physical universe, so that the measurement process it relies on no longer involves entropy in the form of an uncontrolled interaction with a classical measuring apparatus in an unknown microstate. In other words, Bell's theorem is completely meaningless as far as the nature of the actual state or nature of the Universe is concerned; it at best describes a theory of time-ordered, entropy based, projective measurements on open quantum subsystems.
As far as that is concerned, how could one NOT interpret the wavefunction as being "real" (given that a rather lot of it is imaginary if not quaternionic or a number in a generalized geometric division algebra of higher grade:-). It's no more real or less real than any model of a postulated external reality based on our sensory impressions and data, reinforced by reason-based statistical inference.
rgb
(Yeah, yeah, I get it, they are really just trying to say that "time-ordered phenomena apparently exist so the wavefunction must be real", but why bother?. Did any physicist for the last sixty years or so ever doubt this? Should they have, any more than they doubt that reality itself is real and we aren't really all power units in The Matrix?)
Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
The have a new test for the old interference patterns that can't be explained by ading the probability of the individual particles. They get the same result you'll find on any QM book, using a different test.
It is newsworth, but the news is wrong. The authors by their turn didn't help explain anything, the article does have almost the same claims people are repeating, not in a calm tone.
Rethinking email
I blame the trend in the 90's of feeling it was unfair to the stupid children to point out they're stupid.
Now an entire generation thinks their beliefs are facts because their dimwit parents and teachers never pointed out to them that they were idiots.
I'm serious. Shows like Mythbusters dumb down the science, jump to conclusions left right and center, and re-enforce the belief that real science is boring so you need big explosions to keep people interested. Done right it would be brilliant - talking about the limits of their experiments and what other experiments would be needed to more confidently state whether something is a myth or not. Instead they do some limited testing and generalise, jumping to a conclusion as often as possible when there is nothing definite and reserving "plausible" for the rarest of rare cases when they really can't decide what's right or wrong.
Of course people here love Mythbusters and I'll be modded into oblivion, but the truth is when you teach that science is boring when it's not definite and things don't go boom, you get redneck generation.
These posts express my own personal views, not those of my employer
No, I mean his comments about quantum computation indicate that he really doesn't know what he's talking about compared to people who actually study quantum computation. He makes statements that are flat-out false.
Quantum computation isn't really that hard to understand. Quantum mechanics is somewhat unintuitive, but within the context of quantum mechanics, quantum computation is tricky, mathematically, but not difficult to understand.
The fact you called MWI "scientifically plausible" should be the first sign you don't have the first clue what you're going on about.
the wavefunction may or may not be real...But it appears that Dr. Sheldon Cooper is real!!
"For MWI to be "scientifically plausible" it would have to make predictions which could be confirmed or falsified via experiment. "
That is a step in science. Something Feynman taught me when I was much younger.
""superstitious and completely nonsensical""
do you not understand what 'unwittingly' means?
The terms they used invoke a level of mystic thinking; which has spawned a whole field of woo.
BTW: It's starting to look like we will be able to test MWI. Which would bring use to the second step of the scientific process
The Kruger Dunning explains most post on
Plenty of things have no physical reality: like abstract concepts. There is no physical quantity of "good" or "evil", for example. There's not even a physical quantity of "red" (not counting the unrelated color charge from QED). There are physical properties that make things red, but "redness" is not by itself physical.
Red is in principle, observable, measurable and quantifiable and hence it is physical.
All red objects definitely share certain physical qualities that all non-red objects lack, and whatever those qualities are, those are the qualities towards which the word 'red' refers.
I agree about 'good' and 'evil'. there are no physical qualities that all good things can be said to possess which are distinct from non-good things.
No one has a right to their *own* opinion. They have a right to the TRUTH.
What it proves is that if you assume that there is something like a real state of the quantum system at all (and assuming quantum mechanics is actually right) then that real state must include the full wave function.
I've not dug deeply into the paper yet, but I don't understand their measurement apparatus (I'm an experimentalist but not in this field.) Their various states look to me like perfectly ordinary linear polarization states, so their "00/0+/+0/++" apparatus ought to be some kind of linear polarimeter, like a sequence of polarizing beam-splitters with ones at 45 degrees on the arms of one is vertical/horizontal, probably, ultimately, I guess with a recombining of the beams as in a Mach-Zedner interferometer...
But since there is no (apparent) interaction between the two photons I don't see what they mean by a "joint measurement" in this context. Can you give some insight into what kind of measurement apparatus they are actually talking about in the ideal case that would allow them to make the kind of "joint measurement" their argument depends on?
The joint measurement is basically a Bell measurement. I'm no experimentalist, so I don't know how a bell measurement is done in practice, however it seems that linear optics is not sufficient for it. But then, the scheme doesn't demand that the states are states of photons anyway. If you can do arbitraty operations (e.g. you are able to transfer the states into any two-qubit quantum computing setup), you can just transform that basis into a product basis and then measure that. I'm now too lazy (and too tired) to figure it out in detail, but basically you transfer the basis into the standard Bell basis (which needs only local operations; this could even be done with local optics), then you apply a controlled NOT (that's the hard part, but CNOTs have already been implemented in various systems; this is also where the interaction you missed happens), then a local Hadamard on the control qubit. Now you can just measure in the standard basis.
However I'd not be surprised if that would not be the optimal scheme (actually I'd be surprised if it was), and there are better ways to more directly do a Bell measurement. But for that you better ask an experimentalist. :-)
The Tao of math: The numbers you can count are not the real numbers.
A photon is neither a particle nor a wave. A photon is a photon.
Thanks for explaining. One thing I think is what confused me in the first place: Would not an "even number" state be unable to be considred a pure state, though, since it is the combination (with some distribution) of states 2, 4, 6, 8, 10?
I'm unaware of these statements: can you give me a couple of examples, along with references that show these statements are false? I'd appreciate it a lot if you could.
Yes.
The Tao of math: The numbers you can count are not the real numbers.
A theory that does not make testable predictions is not well formulated, but that does not make it "implausible." There is no law of nature that guarantees that everything that is true must be testable by experiment. After all, mathematics allows for the existence of true statements that cannot be shown to be true. There is no reason why this could not be the case for physical reality.
It is reasonable to say that two theories that are reducible to the same mathematical description (in which case there is provably no experimental test than can distinguish them) should be regarded as the same theory, however different their verbal description might sound. And it can also be argued that a "theory" that has been proved mathematically to make no predictions at all (i.e. to be consistent with every possible outcome of every possible experiment) is meaningless (which is still not quite the same thing as implausible). On the other hand, it is important to distinguish between a theory that provably makes no testable predictions and one for which you have not yet managed to think of an experimental test.
No, I'm not, and that's the point. If all videoclips and guitar chords are destroyed, but the song remains in some person's memory, even that memory consists of real physical things.
Someone had to do it.
I must admit I was confused too. The parent seems to be suggesting that the only thing that exists is matter (which is fine), then talking about arrangements as though they are real things. Arrangements can reasonably be argued to not be matter. I would have asserted that only the matter whose physical arrangement is correlated with what I label my thoughts is real, not the arrangement itself. Dismissing the idea of real abstractions only to assert the existence of real abstract arrangements seemed absurd to me.
"Plenty of things have no physical reality: like abstract concepts"
You seem to assume the brain is some sort of magical device. It physically exist in your brain.
The Kruger Dunning explains most post on
They would not be pure states of the (hypothetical) underlying theory, yes. They would still be pure states of quantum theory because quantum theory doesn't know about the badge numbers, only about the machines (and the state "psi badge" belongs to 100% certainty of being produced by the "psi" machine).
The Tao of math: The numbers you can count are not the real numbers.
Because if the "wave function" is a real object, then there is no probabilistic nature to quantum shit - it just means we are currently unable to directly measure the "wave function" without "collapsing" it. If it's not probabilistic, all the fuzziness of quantum physics goes away. Schrodinger's cat is dead, Einstein was right when he said God doesn't play dice, entanglement is horse shit, everyone who works with string theory is a moron, etc.
I don't know if this is a stupid question or not, but: What's the practical difference between something having a state before you measure it but you can't know what it is until you do the measurement, and the state being decided only when the measurement is taken? In what way, other than in contemplating the answer to a purely philosophical question, does it change anything? Is there something the laws of physics allow me to do that I couldn't do with the alternative interpretation?
I suspect the answer is no, because otherwise we would seem to have an experiment available that could prove it one way or the other. But if that's the case then I guess the real question is, why does it matter? Can't we just pick one and use it until such time as its veracity is experimentally disproven? (And wouldn't it make more sense to pick the one that better matches our intuitions, rather than confusing the crap out of everyone with probabilistic non-determinism?)
I found it amazing and eye opening when i looked at a vibrations book and noticed the same basic equations as in my fields and waves class. That is when it hit me. Its all the same stuff! Why wouldn't it act in a similar manner. With that thought in mind, and with everyone talking about reality and thought. I would like to play with a thought experiment. Look at the similarities between thought that generates physical behavior and quantum physics. In my mind I can be anywhere and nowhere at once. Time distorts when in deep thought. Human nature can be as complex as anything I have ever experienced and can only be governed through probability. (if you don't believe me get married and have kids) I do not know if this has any real meaning, but getting out of the box once and a while is helpful.
A macroscopic particle (a drop) is bounded to a dynamic and local wave, both make an object which has exactly what de Broglie's theory is talking about.
I think you have confused "basic philosophy" with religion. Many of your complaints may be valid when it comes to religion, but none of them seem to be actual problems with philosophy.
It's no more real or less real than any model of a postulated external reality based on our sensory impressions and data, reinforced by reason-based statistical inference.
Are sense impressions (or neural states in our visual cortex) objects of perception, or are they means of perception?
Surely this is London, Ontario.
Seven puppies were harmed during the making of this post.
This comment spawned a universe where MWI isn't real!
It's no more real or less real than any model of a postulated external reality based on our sensory impressions and data, reinforced by reason-based statistical inference.
And how do you get sense impressions without sensor cells? And are the sensor cells "external", or is our awareness of them just a model of a postulated external reality?
.... if it can (maybe) be measured: Direct measurement of the quantum wavefunction
But I am fairly certain that they forgot to carry a 1 somewhere.
Vote monkeys into Congress. They are cheaper and more trustworthy.
So "red" does not refer to electromagnetic radiation within a certain range of frequencies?
I guess you are trying to pursue an argument from authority. The only authority I respect is knowledge and intellect, and I don't think you have demonstrated much of either (by making an argument from authority most notably!).
Copenhagen interpretation is not favored much among physicists despite your claims. Maybe 50 years ago.
Copenhagen interpretation posits a hitherto unexplained event: "wave collapse", and even implies that this event is inexplicable, that it rests beyond the domain of physics. Thus, this is just a metaphysical farce. Bohr and Heisenberg probably were simpletons per philosophy, they must have held dualist views or they would not put forward this nonsense. Their interpretation is invalid scientifically prima facie, metaphysical statements can never be scientific.
As for your knowledge of philosophy of science, I don't think you know much either. Falsification is not necessarily required. Verification is sufficient to pursue a theory (induction). Falsifiable cases are icing on the cake in my opinion, and controlled experiments as such are very valuable in practice. Has testable predictions of any kind come from MWI meta-theory? I think it'd be fantastic to have it, but I don't think that this meta-theory, which seems roughly at the level of an interpretation or mathematical theory yet, is not logically unfalsifiable. How did you reach that conclusion, one wonders. And I don't think you've followed the recent publications on MWI either. It has far more credibility among physicists than you think.
On the other hand, if MWI is true (And I did not say it is, but it *can* be true unlike Copenhagen or the ultra-stupid Von Neumann interpretation which makes the dualism in Copenhagen explicit, again Von Neumann was a great mathematician and engineer, but unfortunately he was a frakking moron when it came to philosophy). Then, the wave function of the multiverse would be real, if *this* is true, and then, I think, this would mean that the world-line branches in the Everett multiverse would *not* be disjoint. In other words, perhaps this implies that the observations are not quite real, which would have strange consequences in interpretations.
Anyway, I am not an expert on the subject, but I happen to know the philosophical aspects quite well. You are welcome to offer a proof that MWI meta-theory is fundamentally unverifiable. So far, you have merely asserted such a thing with no citation, no argument, nothing at all. Is this how you conduct all your arguments? They are non-sequitor or very weak.
But yes, you would be a hero among the stupid dualists for defending such a mysticist interpretation, and since most people are idiots who believe in dualism, I think you would even find a fair audience! But to convince an actual philosopher, you have to do better than appealing to the idiocy of the masses.
Before you answer you might want to read this FAQ:
http://www.hedweb.com/manworld.htm
http://www.hedweb.com/manworld.htm#detect
Logically, if there is one thought experiment test of the theory, then, it is also possible to design a more feasible test. At least this seems to show that the theory is not logically untestable. I don't think an AI should be needed, Deutsch is probably flying too high there.
I sometimes like smartasses, but not always. Now, did you actually have an argument, or were you just regurgitating stuff you heard from your dim-witted friends at the faculty?
--exa--
It's an argument from Bayesian statistics, actually. Werner Heisenberg has a long, distinguished track record of highly creditable contributions to physics.
Your track record is unknown, but is exceedingly unlikely to match Heisenberg's. Doesn't take a genius to figure out which side I'm going to side on.
But, hey, being a philosopher makes you much better than a Nobel Laureate physicist who invented quantum mechanics, I guess, so -- bully for you.
With respect to Copenhagen having fallen out of favor, per Max Tegmark's paper "The Interpretation of Quantum Mechanics: Many Worlds or Many Words?", Copenhagen is the overwhelmingly preferred interpretation among working physicists, with MWI coming second. This is from a 1997 survey, so -- your claim that it's been out of favor for 50+ years is simply not true.
(Yeah, yeah, I get it, they are really just trying to say that "time-ordered phenomena apparently exist so the wavefunction must be real", but why bother?. Did any physicist for the last sixty years or so ever doubt this? Should they have, any more than they doubt that reality itself is real and we aren't really all power units in The Matrix?)
Or, apparently, holograms on the edge of an event horizon?
I feel fantastic, and I'm still alive.
Einstein and Schrödinger also regarded the Copenhagen solution as effectively superstitious and nonsense. Bohr and Heisenberg won that round but they are loosing now, this paper shows that the Copenhagen interpretation is of necessity non-local something Einstein tried to prove with the EPR thought experiment. David Bohm and his supporters were prepared to loose locality to provide a hidden variables/quantum potential alternative to the Copenhagen interpretation, however I doubt the supporters of the Copenhagen interpretation and its modern variants are about to embrace non-locality.
Everett and quantum reality rules.
Whether Copenhagen is correct is not at issue. What's at issue is whether it's nonsense. The overwhelming opinion of working physicists, as evidenced by surveys asking which interpretation they subscribe to, is that Copenhagen is not nonsense.
The professor who taught me quantum mechanics summed it up like this: interpretations are our attempt to pretend that we know what the structure of knowledge is, and that we can use that metaknowledge to interpret the confusing world of quantum mechanics. The history of epistemology gives us very little cause to hope that we know anything useful about the structure of knowledge, though. Frankly, the only reason why physicists can philosophize on par with professional philosophers is that the whole of epistemology is bunk, and everyone operates on more or less the same level of bunk. Physicists should do physics and let philosophy attend to itself.
Now, I'm not saying I agree with his entire position... but I've definitely seen enough to make me sympathize with it. If I had to declare myself as an adherent of one interpretation or another, I'd say I belong to the Epistemology Is Bunk Interpretation.
You're a total moron who obviously doesn't know the first thing about philosophy.
What has philosophy brought us? Formal and symbolic logic, science, mathematics ... just for starters!
Fuck, look at you talking about Plato and Descartes like they're the be-all end-all of philosophical thought! (Fuck again, you don't even understand them! How sad is that?)
Why does every idiot think they know everything about philosophy? It's a complex discipline that extraordinarily rigorous and is heavy on the math. It's not a loose collection of empty pontifications -- that's slashdot.
What is with all these people running around spewing facts others figured out long before they were even born, modding down statements they don't agree with and flaunting their neon encrusted everyone but myself is an idiot sign?
What does calling other people idiots or otherwise disparaging them say about yourself?
That's precognition. Canada wasn't absorbed into the US until the resource wars of 2023.
Help stamp out iliturcy.
For those of you who, like me, have no idea what MWI means.
-- Cheers!
Everything is physically real.
This, on the other hand, is not true. Plenty of things have no physical reality: like abstract concepts. There is no physical quantity of "good" or "evil", for example. There's not even a physical quantity of "red" (not counting the unrelated color charge from QED). There are physical properties that make things red, but "redness" is not by itself physical.
One class of things that is not physically real is probability distributions. They describe information we possess about a real quantities, but the distribution itself is not real. They're common in statistical mechanics as well.
I agree it is an uninteresting tautology just like TFA which was actually my point when I said this question itself is pointless and not worth thinking about in the same way untestable hidden variable theories are not worth thinking about.
The rest of this boils down to word games . I assert concepts are not things. Dillusions of man, redness, distributions...etc are all concepts and not things. Therefore they are not real things.
The wave function provides universal consistancy, OTP sources for quantum cryptography and qbits. The process exists in objective reality independent of human attempts to describe it.
What good does it do to discriminate whether a human concept which predicts reality is a reflection of reality? There are less confusing ways to refine theories to be useful to us than playing word games in spaces that are ultimatly untestable and threfore pointless to occupy.
>>Nothing exists in our minds apart from the information we have been given by our senses or that which is a product of the biological processes of our brain.
The key word there is information. Information has no extension (to use Descartes' terminology - it has no length, width, or height), but it is certainly a real thing in our universe.
>>All thought exists physically within our brain as neurochemical interactions, to say otherwise is to presume that there is some as yet unobserved action that does not depend on physical forces going on inside our heads.
Kinda. Let's say there's just one neuron in my brain (hey, maybe I'm a crayfish) that codes for pain. The faster the neuron fires, the more pain I feel. We can establish under the microscope quite easily in this case the NCC (neural correlate for consciousness) for pain. The real kicker than materialists like yourself have trouble with is the very obvious question: where does the FEELING of pain come from? All you can see under a microscope is a series of action potentials, sometimes triggering more rapidly than others. Unless you are doubting the reality of pain (or other qualia), it's unclear why one specific neuron firing quickly creates a feeling of pain, while other might cause feelings of happiness.
In a nutshell, there's two things that have become quite clear: 1) NCCs exist, and 2) We have absolutely no clue how this creates consciousness, or even have a proposed model by which consciousness could exist under our current understanding of physics. This is why your brand of materialism is not especially popular these days - it needs to posit new forms of elementary particles that cannot be detected by any known means, and hence is functionally equivalent to Descartian Dualism. =)
>>"Basic philosophy" is nothing but an ongoing argument between ignorant people over things they know nothing about. For the past three hundred years those people haven't just been ignorant, they've been willfully ignorant. For the past thirty years they haven't just been willfully ignorant, they've been more-or-less criminally ignorant.
You do realize that things like computer science are essentially Applied Philosophy, don't you? Where the fuck do you think that types, classes, etc., came from?
If you want to live in a society without a basis of philosophy, be my guest and move to Antarctica. I'll hang out in my Enlightenment Philosophy based country with its system of natural rights for men.
>>Red is in principle, observable, measurable and quantifiable and hence it is physical.
700nm wavelength electromagnetic radiation is observable, measurable, and quantifiable.
"Red" is a much trickier concept. Even if you have a fMRI hooked up to your visual cortex and can demonstrate you're processing pure 700nm light in exactly the same fashion as your buddy, you have no idea if his experience of red is the same as yours.
If that's too high level, consider instead the fact that the color you experience when viewing 700nm light changes depending on what other sorts of light you absorb in other parts of your retina. For example: http://boingboing.net/2008/02/08/color-tile-optical-i.html
>>The rest of this boils down to word games . I assert concepts are not things. Dillusions of man, redness, distributions...etc are all concepts and not things. Therefore they are not real things.
So you've never experienced redness in your life? That's not "real"? It takes an enormous amount of hypocrisy from an empiricist such as yourself to deny the most primary of empirical observations - seeing with your own eyes. Our internal life are prima facie "real things".
>>The wave function provides universal consistancy... less confusing ways to refine theories to be useful to us than playing word games in spaces that are ultimatly untestable
Dealing with numeric concepts like "700nm light" and claiming this is equivalent to "red" is well and good, except it's wrong. And experiments with our Cartesian Theatre are done all the time.
At first glance, I see this result as supportive of Mohrhoff's interpretation.
"Politicians and diapers must be changed often, and for the same reason."
it isn't clear what Bell's theorem implies as soon as you make quantum mechanics properly relativistic and time reversible within a closed physical universe, so that the measurement process it relies on no longer involves entropy in the form of an uncontrolled interaction with a classical measuring apparatus in an unknown microstate.
Bell's theorem does raise an interesting question. Assuming two distant particles are quantum entangled, they may become disentangled by some interaction at one of the locations. At this moment the other particle also becomes disentangled from that state. How does this affect simultaneity?
Even if this process is not capable of transmitting FTL information, the fact is that there existed two simultaneous events in one frame of reference. How about the other frames of reference? Could they register non-simultaneous quantum disentanglement of two particles?
We certainly don't want the sitting tenants either.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I struggled to read through the paper (rather than the misleading nature blurb).
The authors consider that either (i) the quantum state, |+> or |->, is equivalent to the physical description of the object, or that (ii) there is some other description which produces the outcomes of the quantum calculations, as if it was |+> or |-> say, statistically. They conclude that in (i) experiments are possible where the quantum magnitudes cancel each other, so say outcome of a certain measurement for <Q|+-> system is zero, while if (ii) was true than such scenario is not possible. Their paper is, basically, reminiscent of saying that, if light diffracted on a hole was a "probability" wave rather than "quantum" wave, then there would be no negative interference fringes, because probabilities cannot cancel.
I am pretty sure this paper will go out to trash after the first round of reviews, if it ever gets there. In a way, they do try to restate the Bell's Theorem, and there are no references to the Bell's theorem AT ALL ! Then yes, the states are prepared independently in their example, but are measured together, so THERE IS *entanglement* in fact ! The writing is very poor - they don't say clearly what the quantum scenario predictions are, what the "statistical" scenario predictions are, neither they even define clearly what the "quantum" or "statistical" scenarios are - their definition of "seismic" theorem basically comes down to "If the coin is flipped only once, there is no way to determine by observing only the coin which method was used. The outcome heads is compatible with both. The statistical view says something similar about the quantum system after preparation." Not to mention, finally, that any self-respecting quantum theory student did a calculation of the sort (probabilistic picture + negative interference of quantum states) in their late university years.
I can only feel sorry for the researchers at the Imperial College of London who apparently had been away from the developments in physics for the past 50 years since Bell's inequalities had been formulated and "hidden variables" and locality debate raged on. I can only suggest them to visit wikipedia before going ahead with submitting this paper, http://en.wikipedia.org/wiki/Bell_theorem. Also it is very frustrating that nature would publish a blurb like that, after the series of scandals regarding pubs in nature, such as about quite recent stem cell research "discoveries" in Korea, it really makes you think twice about what the hell their editors are thinking.
I'm sorry, that's just silly. In case there's some confusion, I wasn't attempting to talk about some fuzzy headed concept of information as an existence unto itself. What I meant by 'information we have been given by our senses' was the collection of impulses that have run along our sensory neurons to stimulate the systems of our brains. This 'information' is very measurable, unfortunately Descartes missed out on that information by a few hundred years. As for pain, I don't doubt the existence of the feeling of pain but I do affirm that it does not exist separate from the physical systems that perceive it. Even emotional pain has been shown to trigger the same sites in the brain responsible for interpreting physical pain. The 'FEELING' of pain is just that interpretation of those signals as processed by particular centers in the brain, as is pleasure and even higher emotions which, while much more complex in some ways, still rely on the same underlying functions.
There are no 'spooky' forms floating around inside our heads however, I am not saying that our perception of the world is not an impressive and wonderous mystery. It is very true that we do not know exactly how consciousness arises from the human brain but we do know that the human brain is necessary to the existence of consciousness. We do not need to rely on any imagined elementary particles just because we do not fully understand consciousness, making such a leap makes no sense and I'm not sure why you're trying to sneak it into the conversation without a proper explanation.
I'm not sure you are following me at all.
1. Have you presented any argument whatsoever that MWI is logically unfalsifiable? Where is that argument?
2. I am actually quite knowledgeable about Bayesian statistics. The mathematical formulation of quantum mechanics does NOT include any interpretation, that's why it's called interpretation in the first place. That you conflate Bayesianism with interpretations of QM is curious, as if Bayesianism supports any particular interpretation of QM, it does not do that! Bayesian vs. Frequentist debate applies to every application of probability theory. However, you seem to be, ignorantly, thinking that the epistemological interpretation in Bayesian statistics means that the probabilities in QM do not have an ontological character. This is wrong on so many levels. First, probabilities in QM are not identical to the wave function. You obtain the probability density function only after finding the square of the magnitude of the wave function right (by multiplying it with its conjugate)?. So, your statement is obviously meaningless, you are just another dualist talking about this religiously. Let me ask you: since you believe that , you also believe that there are non-physical things in the world, right? For Copenhagen and equally banal Von Neumann interpretations boil down to the claim that there are magical, inexplicable, non-physical "things" or "events" in the universe, along with what we consider to be real and physical (observations).
3. And have I said that this study supports MWI, or that MWI is my preferred interpretation? I did not. However, I do think that the notion of decoherence is much more scientifically plausible, as it does not contain vague, and unexplained pseudo-mechanisms like wave function collapse. The way I see it, "wave function collapse" is an inadequate attempt at explaining a real phenomenon, and it posits too much therefore it fails Occam's razor. It seems to be a behavioral description of a class of events actually, without revealing a consistent theory of "how", and that is quite suspicious in itself, however, yes, I anticipate that there would also be things that are incorrectly predicted by "wave function collapse". I do not find the rest of the Copenhagen interpretation problematic.
4. The issue of which interpretation is correct is the key to a GUT, therefore it has scientific significance. Good luck with starting from Copenhagen interpretation and obtaining a GUT! There are several plausible interpretations such as consistent histories, one of them could be true, but not Copenhagen or Von Neumann, which are fundamentally mysticist, it really is just medieval solipsism. Mystical stuff, especially solipsism, isn't physics. According to your celebrated Heisenberg, the particles aren't real but their appearance is real. This is just glorified stupidity, sorry.
5. I am equally suspicious about the everett interpretation of quantum computation, that quantum computers we construct harness the computational power of parallel universes. I suspect that as we build larger quantum computers we ought to be able to measure how much of this is true. Thus, perhaps this issue will be clarified during quantum computing experiments.
6. You also don't seem to understand that the reality of the wave function would not "destroy" Copenhagen interpretation, it would just change it slightly. Both observations and wave functions can be real in an interpretation. That subject is a lot more complex than you seem to think it is:
http://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics#Comparison
Philosophers of physics held many conferences on the subject, with apparently no real resolution, so if you just insist on this mysticist, semi-scientific interpretation go for it in your isolated space, but please stop preaching it to your students, and stick with math and experiments!
--exa--
And if we simply define color optically rather than psychologically?
The parent never referred to redness.
That's the point, if one is inclined to examine the metaphysical philosophy underlying quantum mechanics or any other mental map of a supposed external reality. The questions involved are very old, and the only reasonable path from Humian skepticism to knowledge as a network of reasonably consistent probable truth is that laid out originally by Richard Cox, then emphatically recapitulated by E. T. Jaynes. A great deal of bootstrapping occurs as we seek the optimum solution to this problem -- as in belief in our neural states and visual cortex comes from analyzing sensory impressions that, it appears, occur in our neural apparatus and visual cortex, both objects and means consistently. However, both the "evil genius"/Matrix and the solipsistic solutions exist as an eternal counterexample against assertions that we can be certain of what external reality REALLY is.
Given that, there has never been any good reason (post 1930s) to doubt the "reality" (objective existence) of a wavefunction, any more than there is good reason to doubt the reality of the electron in a wavefunction or the atom made out of the electrons and so on. By this I don't mean that we can't and don't continue to doubt -- I mean that in the near infinity of possible notional "alternative explanations" for all of the experiments and observations we make about "reality", the simplest solution that best fits the facts has long, long been that wavefunctions are as real as anything else -- they are a provisional truth in excellent agreement with experiment and consistently connected with an entire system that works pretty well.
Can we be certain that it is correct? Of course not. But no reasonable person has been able to doubt their reality more than the alternative explanations, as the alternative explanations have little explanatory power and or usually openly inconsistent in one place or another. Most of the objections are predicated upon our essentially classical everyday experience and the fact that our brains are evolved to optimally "think" classically, but it has long been known that quantum mechanics is as logically/mathematically consistent as classical mechanics -- indeed, if you read Schwinger's lovely "Quantum Kinematics and Dynamics" you can see the precise point where the worldview diverge, from the purely common sense description of measurement processes as an abstract algebra.
rgb
Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
An interesting hypothesis indeed, although I remain a wee bit skeptical. But a good provisional explanation, no doubt. Leonard writes very convincingly...;-)
rgb
Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
No, there are multiple ways that there is "redness".
The most biologically direct is that it's an EM response spectrum that one of the cone types in our eyes is sensitive to. You can excite the red cones and perceive redness without EM radiation from the "red" frequency range. (To be more pedantic, really anything our brains perceive as red counts, even if the red cones were not directly excited.)
Then, there is a portion of the EM spectrum that could be called "red".
Then, there are molecules that filter or reflect light such that, with the appropriate lighting, causes it to appear red. "Redness" isn't really an internal property of these molecules, though, since whether they appear red depends (in constructed cases, strongly depends) on the input lighting.
Shor's algorithm is probably the best example.
In The Fabric of Reality, he says:
When Shor's algorithm has factorized a number, using 10500 or so times the computational resources that can be seen to be present, where was the number factorized? There are only about 1080 atoms in the visible universe, an utterly minuscule number compared with 10500. So if the visible universe were the extent of physical reality, physical reality would not even remotely contain the resources required to factorize such a large number. Who did factorize it, then? How, and where, was the computation performed?
His general view is that Shor's algorithm is performing the classical factorization computation but in parallel using quantum-mechanical superposition. (His argument from this is that the superposed states must map to alternative universes, but that's not really necessary to go in to.) This is a common but completely incorrect interpretation of Shor's algorithm. As far as I know, the only way to come to this incorrect understanding is to not really be familiar with how Shor's algorithm works, but just what its end result is. Shor's algorithm doesn't even really perform factorization, per se. It happens to be able to perform factorization in modular arithmetic space (which is the kind that is cryptographically relevant) because it turns out that you can turn modular factorization into a period-finding problem. Shor's algorithm is really just an efficient quantum-mechanical period-finding algorithm, kind of like a quantum-mechanical Fourier transform. None of what it does is mysteriously parallel. (I think Mermin's quantum computation book is a good source for understanding how Shor's algorithm operates. He also addresses, at least in some of the talks I've been to on the subject, common misinterpretations of quantum computation.)
Again, wrong perspective. Particles never "become" entangled. This is a local view that directly contradicts relativistic quantum field theory and is inconsistent. Particles -- and I mean every particle in the universe, at least indirectly, if one views it as a manifold -- are always entangled. There is just one "Universal" wavefunction, and it either must be stationary (closed Universe) or it else we have to work very hard to understand information conservation as we observe it in the part of the Universe we can see. The only approach, either way, is to follow the general derivation of the Generalized Master Equation, the partition of a presumed stationary universal wavefunction into a "system" and a "bath". The system is treated as an internally deterministic time evolution, but the bath is treated statistically not because it isn't really quantum mechanical, but because we cannot know its initial state any better than probablistically, we cannot prepare it in a known pure state, its state is known classically. Hence a diagonal trace and the introduction of projection valued operators. This is where Bell's theorem appears, and where the whole dogma of the measurement of quantum SUBsystems appears, where an effective random phase approximation appears, where quantum indeterminacy in the subsystem appears. It's all smoke and mirrors -- it doesn't exist in the proper original statement of the problem, it only appears at a certain point where we make necessary approximations due to our IGNORANCE of the state of the bath.
It's all about information.
Describe to me the "time evolution of entanglement" otherwise. You can't. "Entanglement" occurs only when you mentally prepare the system initially in a product state, and then allow time evolution to carry you into a matrix representation. But this is a false dilemma -- the system was NEVER really in a product state -- it was at best in a diagonal state in the matrix representation in the first place, and ANY interaction with the outside world suffices to move you out of it. That interaction with the outside world cannot ever be turned off, right? It is merely -- incorrectly -- ignored. Hence Schrodinger's Cat is a quantum paradox only if you presume COMPLETE ADIABATIC DECOUPLING of the box and infernal device from the rest of the Universe, which is of course absurd.
rgb
Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
He's just conflating "concrete" and "real". I think that's a stupid position, but then we'd just be arguing philosophy that was covered by the Greeks.
And if any of those multiple ways is correct, then DM9290 is correct. But I would claim that the optical definition is more fundamental physically.
I cannot add anything more insightful than what Matti P. has written at http://matpitka.blogspot.com/2011/11/are-quantum-states-only-figments-of.html er, maybe I could add to it, but I'm working on other theories... reality or non-reality does not matter...
DM9290 was citing that in a previous post, but did not say it (him/her)self.
Apart from seeming like a play with words, I always thought that argument had a logical hole...
Let's define the property P as 1) being a unicorn, and 2) existing.
Now let's look at a hypothetical object p with the property P. Does p exist? Yes, obviously, since it follows from the definition of P. Therefore, there exists at least one unicorn.
What did we do wrong? Well, by defining the property P as both being a unicorn and existing, we are implicitly assuming that it's possible to have those two properties, i.e, that there is an object which both exists and is a unicorn.
In the same way, by defining the property G as "being God", and defining God in such a way that it implies existing, we're implicitly assuming that there exists an object which fulfils the definition of God.
If the wavefunction is a physical object, what are its physical dimensions?
Actually, it remains probabilistic and we keep the cat and entanglement. The probabilistic view claims that there's a there there but we cannot see it clearly. The realist view says that there's no there there.
That is, in the probabilistic view, a particle has a definite position and a definite momentum but we cannot know both at once. The realist view says that the particle actually doesn't possess those traits at all until we collapse the waveform. More and more evidence suggests the latter view even though mainstream thought resists going that way because it's just so odd.
>>And if we simply define color optically rather than psychologically?
Sounds easy, please explain. =)
It is easy for pure hues. We can define them in terms ranges of frequencies of electromagnetic radiation. Something like brown would be harder to define.
I think it is pretty clear what Bell's inequality shows. First of all, Bell showed that von Neumann's proof that you couldn't have hidden variables was wrong and he showed where it was wrong (von Neumann had assumed 'no distrubance'). Secondly, he showed that only non-local hidden variable theories, like Bohm's, could reproduce quantum mechanics (QM). Finally, he showed that QM predicts correlations that cannot be explained by a classical picture of objects and attributes. These correlations have since been measured and confirmed, leading to Alain Aspect's Nobel prize. These results are not conclusive because such as small number of correlations are found. It is possible that just the results that would give a classical result are missing, though no-one has an explanation for why this might be.
Bohm's hidden variable theory is not relativistic and so needs more work to be a credible contender for a realist interpretation of the wave function. In the meantime, the Born interpretation says that the wave function is just a probability distribution, the Many Worlds interpretation says that the wave function is real but split across many parallel universes while the Copenhagen Interpretation explicitly says that the wave function is not real. This is why finding a reason to think the wave function real is so important.
John F Schlesinger Temenos UK
>>It is easy for pure hues. We can define them in terms ranges of frequencies of electromagnetic radiation.
There's two problems with that:
1) Sorites - sure, maybe 700nm light is "red", but is 701nm? 702nm?
2) The perception of redness is only tangentially related to the EM wavelength of light being received. In other words, 700nm can be perceived as yellow or orange under various circumstances.
That's why it's hard to equate wavelength with color perception.
Thanks... that clears up my basic confusion. I didn't see how it could be done with linear optics either, but not being in the field wasn't sure if there wasn't something I was missing.
Having read the paper in more detail I'm not overwhelmed by their argument.: "That is, 'Preparing a photon in the same quantum state will sometimes result in photons in different physical states' does not imply 'Preparing a photon in different quantum states will sometimes result in photons that are in the same physical state'. The former proposition is the statistical interpretation. The latter is the assumption that the author’s argument depends on."
Blasphemy is a human right. Blasphemophobia kills.
"Red" is a much trickier concept. Even if you have a fMRI hooked up to your visual cortex and can demonstrate you're processing pure 700nm light in exactly the same fashion as your buddy, you have no idea if his experience of red is the same as yours.
Almost no one uses 'red' as to mean the experience of viewing 700 nm light. And words obtain meaning from the way they are used by speakers.
They mean the surface of the car has certain visual qualities (i.e. it reflects the same color as a tomato, or cherry). They are attempting to describe physical properties of the surface without understanding how light works.
We teach children color entirely by reference to physical examples of the color. This is the only way we teach children colors. We point at physical objects and say "Red" and then repeat this over a variety of objects until the chid understands the physical property we are referring to (as opposed to the shape of the object or size).
Interior decorators use color swatches because we need CONCRETE examples to describe color.
In lay-english, color refers to an object's physical properties. (regardless of the fact that science has subsequently determined that these physical properties are emergent, and depend on the object, the ambient light, and the structure of the observers retina).
Something isn't abstract simply because the speaker doesn't understand how it works. It is based on whether or not it is based on concrete examples.
I would argue that "color" is an abstract concept. "red" is a concrete example of a color. 'Red' it is defined by reference to real physical objects which we agree to call "red". Without those concrete examples of 'red', then the word is utterly meaningless.
Lets invent a new color called 'X-Ray'. This is the color of x-rays that you can't see but it is what x-rays look like to super-man when he uses his x-ray vision. I have just created an abstract color. Contrast this with 'red'.
No one has a right to their *own* opinion. They have a right to the TRUTH.
Sure, I guess, but personally I don't know of many physicists who believe, or teach, that the Copenhagen interpretation is correct and everybody is dubious of the many worlds hypothesis because a) there is no obvious way to test it; and b) it causes an explosion of nature to cover not just Leibnitz' (or Dr. Pangloss') "best of all possible worlds" but all possible worlds. One might as well believe in magic as this is a religious assertion until it is demonstrated that there is an experimental observation that not only "can" be explained by many worlds, but REQUIRES many worlds to explain it and of course mathematically that is not only not true it is hardly possible within the confines of quantum theory as we use it computationally.
Besides, it isn't necessary. As noted, measurement is essentially a classical process and most of the "paradoxes" in any theory of quantum mechanics come from e.g. inappropriately separation and diagonalization of the Universe into system and everything else. The simplest explanation that agrees with the observations has ALWAYS been that the wavefunction of an electron is as real as the electron itself, although the idea of a "single electron wavefunction" is a bit of a myth, an idealization that we can basically never realize. Insisting that it be unreal clearly is an a priori assertion without any foundation. Insisting that it is real in an infinite hypervolume of entire spacetime continua with combinatorial/permutative complexity is is an a priori assertion with infinitely less foundation. Assigning it the provisional value of being real unless or until proven otherwise has been the default ever since it was shown that electrons exhibit two slit interference and all other wave phenomena in the appropriate context, since Aharonov-Bohm, since the electron microscope, really since de Broglie.
With that said, I'm quite glad to see that there is MORE evidence confirming my longstanding beliefs -- I'd just assert that it is just more, not the first or only.
rgb
Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
I wasn't trying to relate wavelength to color perception. I simply tried to define color optically; I wasn't claiming that it would hold perceptually. As for the sorites problem, I did mention a range of wavelengths. Of course, setting the boundaries might be tricky.
Thanks... that clears up my basic confusion. I didn't see how it could be done with linear optics either, but not being in the field wasn't sure if there wasn't something I was missing.
Having read the paper in more detail I'm not overwhelmed by their argument.: "That is, 'Preparing a photon in the same quantum state will sometimes result in photons in different physical states' does not imply 'Preparing a photon in different quantum states will sometimes result in photons that are in the same physical state'. The former proposition is the statistical interpretation. The latter is the assumption that the author’s argument depends on."
The authors (as far as I can see) don't claim the latter to follow from the former. However in my understanding their point is that if two different physical states imply two different quantum states then the quantum state is part of the physical state (because the quantum state then is uniquely determined by the physical state). And since that's what they want to prove by contradiction, they of course have to assume that this is not the case, i.e. that the same physical state can be part of different quantum states.
The Tao of math: The numbers you can count are not the real numbers.