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The article seems interesting but I am afraid I do not understand quantum physics well enough to understand it fully - could someone more knowledgeable please t

by honzzz 12y ago

The article seems interesting but I am afraid I do not understand quantum physics well enough to understand it fully - could someone more knowledgeable please try to explain it like I am five? How would quantum mechanical perception of the world for common people look like?

hliyan 12y ago
I explain quantum physics (or at least the underlying principles) to myself this way: 1. Quantum fluctuations are the random number generator function of the universe. Without which, the universe will be utterly uniform and lacking detail. All detail (or information) is born through quantum fluctuations. 2. The universe has a finite resolution -- you zoom in enough and you reach a point where you 'see' the 'pixels' of the universe and see no further. This applies to matter, energy, space and time. I may be oversimplifying or even understanding it wrong, but to me, denying either (1) or (2) eventually leads to a reductio ad absurdum -- 1) a universe that is a uniform, featureless soup, or 2) infinite information density. * As a side-note, denying (1) also results in denying free will -- all future states of the universe becomes classically predictable, including the thoughts and behaviors of conscious beings in it. EDIT: sorry, I know you asked about perception. I've never quite been able to explain waveform collapse to myself. Intuitively, it feels like the universe does lazy evaluation -- all variables are in flux until read?
- mangeletti 12y ago
  Worth noting is that this idea of quantum randomness has recently been all but proven wrong in an experiment involving water ripples[1]. Einstein had this idea of "hidden information" (i.e., just because we're not advanced enough yet to observe something doesn't mean it doesn't exist), but it has always been regarded as ludicrous. In other words, the resolution of the universe may not be finite, but since the parts involved in infinity are impossible to comprehend or list in a peer reviewed paper, this drives mathematicians bananas. In the end, the human ego might prove to be the real Strong Force in the universe. [1] http://www.pbs.org/wgbh/nova/blogs/physics/2014/09/quantum-physicists-catch-a-pilot-wave/ http://www.pbs.org/wgbh/nova/blogs/physics/2014/09/quantum-p...
  - semi-extrinsic 12y ago
    Sorry, but I have to correct this. 1) It's very far from proven that water pilot wave experiments say anything at all about the quantum world. Most physicist believe they don't tell us anything about it, they just provide a simpler system that "looks quantum". This quote is from the article you linked: “It is not by itself capable of representing very much physics,” Oxford University physics philosopher David Wallace told Quanta earlier this year. 2) Physicists have no problems with handling/removing infinities, just see regularization or renormalization in quantum field theory. 3) In general, this comic applies to anything you read in popsci sources: https://xkcd.com/1240/ https://xkcd.com/1240/
    - mangeletti 12y ago
      Good points. Pertaining the 1st and 3rd points though, an important thing to keep in mind is that a lot of big scientific ideas come from philosophers and even science fiction writers, and I wouldn't be shocked if a few thoughtful comic strips joined the club. Most scientists are just technicians, applying existing knowledge to test existing theories. This means that a scientist doesn't necessarily have more qualified of opinions than any other person does.
      - lgas 12y ago
        While technically correct (the best kind of correct!) your final sentence seems to be a fairly ludicrous position to me -- in general scientists spend (quite a lot) more time learning about biases and other flaws in rigorous thinking and how to avoid them, studying and discussing all of that existing knowledge, learning how to perform experiments, performing them, interpreting the results, etc. all of which lead directly to them having a much more qualified opinion than "any other person" does.
      - semi-extrinsic 12y ago
        Re: your second-to-last sentence: it may well be that many scientists appear as if they are technicians applying existing knowledge to test theories. But that is partly because the only way to go beyond accepted theories is often to find where those accepted theories start breaking down, and then see how they break down.
- diogofranco 12y ago
  "As a side-note, denying (1) also results in denying free will." Denying (1) clearly denies free will since we are talking about a purely deterministic universe. But notice that (1) holding true doesn't really open up any space for free will anyway. With (1) you now have randomness as well as causality in the universe, but how does that mix produce free will? If the conscious beings thoughts and behaviours are stuck in determinism/randomness, there is no free will. I've seen that quantum argument for free will thrown around, but random events in the brain giving rise to our thoughts and actions is still the antithesis of free will. Whether you're doing something because of a chain of cause and effect, or because of random fluctuations in the very small, you're not doing it because you want to do it.
  - hliyan 12y ago
    True. Since we are on the subject of perception, what if I were to postulate (as a lot of people have done before) that what we call free will is just our perception of randomness in the brain ex post facto? Some studies have shown that decision neuron clusters fire a fraction of a second before the subject appears to make the conscious decision. Anyway, apologies for potentially derailing the thread by throwing free will into the discussion.
- onetimeuser98 12y ago
  I don't agree but beware - non-educated unscientific rant ahead, personal view only You can only measure nature with nature ..or universe with the same universe, - or - universe can only measure it self with/by itself; now measurement is an interaction - you have to interact(either directly or indirectly) with what you are trying to measure to get some information. Since you are using "parts" of the universe(like photon/electron beams, stones, chopsticks) to measure other parts of the same universe, of course there are limits on your precision and artifacts within those measurements. Lets do a gedankenexperiment; imagine that you just entered a porcelain shop but your vision is based on arbitrary-sized plastic projectile gun and a (smart)detector wall that detects all projectiles that bumped of a scanned surface within a certain angle. Now there is only a range of momentums(velocity/weight combinations) that would let you scan that environment within an acceptable resolution - the point is that you can't have an arbitrary resolution(either there is air-resistance or unavoidable damage to the environment or or).. I'll jump ahead a few steps and go right to the underlying question, and that is whether the universe is deterministic or not - which in context of the above is actually pretty straight-forward(again, personal view) - since as "inhabitants" of the universe we want to measure we are bound to use parts of the universe to do our measurements, newtons predicable clockwork universe indeed has its limitations(and I really don't see why this is such an issue when c is accepted without friction, if you have no problems dealing with c why on earth do you have such problems with this which directly follows). Regardless of whether we live in a deterministic universe or not we can't have arbitrary resolution so from practical point of view - for us - its the same as if the universe "at-its-core" was not deterministic(there is no way to get that probability line under control when time increases). Now as a pure philosophical question, whether our universe is really deterministic or not depends on the model we use(in "bubble-like-multiverses" there is no interaction between universe-bubbles possible hence deterministic, in eternal inflation models it gets spread from deterministic to non-deterministic but for all models with interacting universes - only your imagination is the limit, seriously, very potent drug) All in all, one thing is sure - we are the universe experiencing it self sooo enjoy
  - hliyan 12y ago
    > "you are using "parts" of the universe(like photon/electron beams, stones, chopsticks) to measure other parts of the same universe" That's a very insightful way to put it. To me, that completely and intuitively explains uncertainty -- every form of perception is a form of interaction. So our brains have just evolved to treat them as two different concepts because we perceive using very weakly interacting mechanisms (such as light and sound) and that gives the illusion of pure perception. However, that does not invalidate my points about the other two aspects of quantum physics -- fluctuations and quantization -- does it?
- malka 12y ago
  > I've never quite been able to explain waveform collapse to myself. Intuitively, it feels like the universe does lazy evaluation -- all variables are in flux until read? There are many interpretation. This page could be relevant to your interest : https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics https://en.wikipedia.org/wiki/Interpretations_of_quantum_mec...
- altrego99 12y ago
  Also, the random numbers generally interact like 2-dimensional vectors when not observed, and in a different way, like probabilities between 0 to 1, the moment they are observed.
- heed 12y ago
  All experimental evidence points to space being continuous, not discrete.

by honzzz 12y ago

hliyan 12y ago

I explain quantum physics (or at least the underlying principles) to myself this way: 1. Quantum fluctuations are the random number generator function of the universe. Without which, the universe will be utterly uniform and lacking detail. All detail (or information) is born through quantum fluctuations. 2. The universe has a finite resolution -- you zoom in enough and you reach a point where you 'see' the 'pixels' of the universe and see no further. This applies to matter, energy, space and time. I may be oversimplifying or even understanding it wrong, but to me, denying either (1) or (2) eventually leads to a reductio ad absurdum -- 1) a universe that is a uniform, featureless soup, or 2) infinite information density. * As a side-note, denying (1) also results in denying free will -- all future states of the universe becomes classically predictable, including the thoughts and behaviors of conscious beings in it. EDIT: sorry, I know you asked about perception. I've never quite been able to explain waveform collapse to myself. Intuitively, it feels like the universe does lazy evaluation -- all variables are in flux until read?

mangeletti 12y ago
Worth noting is that this idea of quantum randomness has recently been all but proven wrong in an experiment involving water ripples[1]. Einstein had this idea of "hidden information" (i.e., just because we're not advanced enough yet to observe something doesn't mean it doesn't exist), but it has always been regarded as ludicrous. In other words, the resolution of the universe may not be finite, but since the parts involved in infinity are impossible to comprehend or list in a peer reviewed paper, this drives mathematicians bananas. In the end, the human ego might prove to be the real Strong Force in the universe. [1] http://www.pbs.org/wgbh/nova/blogs/physics/2014/09/quantum-physicists-catch-a-pilot-wave/ http://www.pbs.org/wgbh/nova/blogs/physics/2014/09/quantum-p...
- semi-extrinsic 12y ago
  Sorry, but I have to correct this. 1) It's very far from proven that water pilot wave experiments say anything at all about the quantum world. Most physicist believe they don't tell us anything about it, they just provide a simpler system that "looks quantum". This quote is from the article you linked: “It is not by itself capable of representing very much physics,” Oxford University physics philosopher David Wallace told Quanta earlier this year. 2) Physicists have no problems with handling/removing infinities, just see regularization or renormalization in quantum field theory. 3) In general, this comic applies to anything you read in popsci sources: https://xkcd.com/1240/ https://xkcd.com/1240/
  - mangeletti 12y ago
    Good points. Pertaining the 1st and 3rd points though, an important thing to keep in mind is that a lot of big scientific ideas come from philosophers and even science fiction writers, and I wouldn't be shocked if a few thoughtful comic strips joined the club. Most scientists are just technicians, applying existing knowledge to test existing theories. This means that a scientist doesn't necessarily have more qualified of opinions than any other person does.
    - lgas 12y ago
      While technically correct (the best kind of correct!) your final sentence seems to be a fairly ludicrous position to me -- in general scientists spend (quite a lot) more time learning about biases and other flaws in rigorous thinking and how to avoid them, studying and discussing all of that existing knowledge, learning how to perform experiments, performing them, interpreting the results, etc. all of which lead directly to them having a much more qualified opinion than "any other person" does.
    - semi-extrinsic 12y ago
      Re: your second-to-last sentence: it may well be that many scientists appear as if they are technicians applying existing knowledge to test theories. But that is partly because the only way to go beyond accepted theories is often to find where those accepted theories start breaking down, and then see how they break down.
diogofranco 12y ago
"As a side-note, denying (1) also results in denying free will." Denying (1) clearly denies free will since we are talking about a purely deterministic universe. But notice that (1) holding true doesn't really open up any space for free will anyway. With (1) you now have randomness as well as causality in the universe, but how does that mix produce free will? If the conscious beings thoughts and behaviours are stuck in determinism/randomness, there is no free will. I've seen that quantum argument for free will thrown around, but random events in the brain giving rise to our thoughts and actions is still the antithesis of free will. Whether you're doing something because of a chain of cause and effect, or because of random fluctuations in the very small, you're not doing it because you want to do it.
- hliyan 12y ago
  True. Since we are on the subject of perception, what if I were to postulate (as a lot of people have done before) that what we call free will is just our perception of randomness in the brain ex post facto? Some studies have shown that decision neuron clusters fire a fraction of a second before the subject appears to make the conscious decision. Anyway, apologies for potentially derailing the thread by throwing free will into the discussion.
onetimeuser98 12y ago
I don't agree but beware - non-educated unscientific rant ahead, personal view only You can only measure nature with nature ..or universe with the same universe, - or - universe can only measure it self with/by itself; now measurement is an interaction - you have to interact(either directly or indirectly) with what you are trying to measure to get some information. Since you are using "parts" of the universe(like photon/electron beams, stones, chopsticks) to measure other parts of the same universe, of course there are limits on your precision and artifacts within those measurements. Lets do a gedankenexperiment; imagine that you just entered a porcelain shop but your vision is based on arbitrary-sized plastic projectile gun and a (smart)detector wall that detects all projectiles that bumped of a scanned surface within a certain angle. Now there is only a range of momentums(velocity/weight combinations) that would let you scan that environment within an acceptable resolution - the point is that you can't have an arbitrary resolution(either there is air-resistance or unavoidable damage to the environment or or).. I'll jump ahead a few steps and go right to the underlying question, and that is whether the universe is deterministic or not - which in context of the above is actually pretty straight-forward(again, personal view) - since as "inhabitants" of the universe we want to measure we are bound to use parts of the universe to do our measurements, newtons predicable clockwork universe indeed has its limitations(and I really don't see why this is such an issue when c is accepted without friction, if you have no problems dealing with c why on earth do you have such problems with this which directly follows). Regardless of whether we live in a deterministic universe or not we can't have arbitrary resolution so from practical point of view - for us - its the same as if the universe "at-its-core" was not deterministic(there is no way to get that probability line under control when time increases). Now as a pure philosophical question, whether our universe is really deterministic or not depends on the model we use(in "bubble-like-multiverses" there is no interaction between universe-bubbles possible hence deterministic, in eternal inflation models it gets spread from deterministic to non-deterministic but for all models with interacting universes - only your imagination is the limit, seriously, very potent drug) All in all, one thing is sure - we are the universe experiencing it self sooo enjoy
- hliyan 12y ago
  > "you are using "parts" of the universe(like photon/electron beams, stones, chopsticks) to measure other parts of the same universe" That's a very insightful way to put it. To me, that completely and intuitively explains uncertainty -- every form of perception is a form of interaction. So our brains have just evolved to treat them as two different concepts because we perceive using very weakly interacting mechanisms (such as light and sound) and that gives the illusion of pure perception. However, that does not invalidate my points about the other two aspects of quantum physics -- fluctuations and quantization -- does it?
malka 12y ago
> I've never quite been able to explain waveform collapse to myself. Intuitively, it feels like the universe does lazy evaluation -- all variables are in flux until read? There are many interpretation. This page could be relevant to your interest : https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics https://en.wikipedia.org/wiki/Interpretations_of_quantum_mec...
altrego99 12y ago
Also, the random numbers generally interact like 2-dimensional vectors when not observed, and in a different way, like probabilities between 0 to 1, the moment they are observed.
heed 12y ago
All experimental evidence points to space being continuous, not discrete.