Quantum uncertainty vs determinism

Discussion in 'Physics & Math' started by Laika, May 18, 2006.

  1. c'est moi all is energy and entropy Registered Senior Member

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    I'm sorry, now that I re-read it, you could interpret it as if I refer to you, Billy T. I meant Bohm's philosophical writings. In his book "Wholeness and the implicate order", he mixes philosophy, linguistics and physics. Not that this is a problem - I think it's wonderful. But since I'm no physicist, the chapters about the maths of his bohmian mechanics are too difficult for me (except for some parts).

    But there are many good links about Bohmian mechanics:

    http://www.mathematik.uni-muenchen.de/~bohmmech/BohmHome/bmstartE.htm
    http://www.math.rutgers.edu/~oldstein/
    http://yepes.rice.edu/PhysicsApplets/TwoSlitFrame.html (great applet!)
    http://www.phys.port.ac.uk/fpweb dell/

    I'm trying to understand it as good as I can.

    But I've never seen any statement that each particle is associated with its unique pilot wave.

    I did read some more which is important in this respect: you have the quantum potential, which is a subsystem of the super quantum potential. It is on the leven of this super system of implicate order that particles are "created" (unfolded) and destroyed (enfolded) making the impression to be corpuscles moving through space, when in fact they are an emergent phenomenon related to another reality. This would in turn explain the discrepancies between a Newtonian description and a quantum. The deeper you go ("Look") to better you are able to perceive that their "normal" behaviour is the illusion of how you approach them.
     
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  3. c'est moi all is energy and entropy Registered Senior Member

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    I accidently came across Hiley and Bohm's "Undivided universe" at the library, so of course I took it with me, together with "The structure and interpretation of quantum mechanics" from Hughes. The latter starts with the Stern-Gerlach experiments. It's similar to how Feynman discusses it, though Feynman does go deeper into the details. I'm comparing the approach with the one of Hiley and Bohm.

    btw, in his introduction he mentions indeed that each particle is "however, profoundly affected by a wave that always accompagnies it."

    I wonder if your objection is not just a matter of how you see things. For example, you would say that a magnet is always accompagnied by a magnetic field. You wouldn't say that this is problematic, because the magnetic field has to know to which magnet is belongs. I think "pilot waves" are misleading in that sense. Virtual photons that surround an electron like a swarm of appearing and disappearing bees, EXACTLY know how to behave, in order to maintain an apparent constant negative charge. Each particle has its quantum field - called a pilot wave. That's the association. The reason why no confusion occures, is as mysterious as how inertia works, or why virtual particles create the forces we see. At a point, you just have to say: that's how it (may) work(s).
     
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  5. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Thanks for your “Bohm group” references. The one above gave an Email address and I plan to send the following to them, but first post it here to make sure it is clear and permit someone here to point out the flaw, if any, in my argument against Bohm’s ideas about quantum mechanics

    Dear Bohm Group:

    I do not like the Copenhagen interpretation of Quantum Mechanics, QM, because a “measurement” is something essential, but outside of the theory. Thus, Bohmian QM is very attractive to me, but I think not true. I hope you will find a flaw in my argument against the validity of Bohm’s QM that follows.

    Imagine two electrons, A & B, launched successively (B after A) into a two-path interference system, which has equal path lengths when A is launched, but one path is made an odd multiple of half wavelengths shorter when B is launched and I will here after call that path the “short path.“

    Thus, there is one most probable constructive interference location on a scintillation screen for A to excite, but two equally probably locations for the scintillations produced by B.

    Now designate the transit time of A through either of the equal “long paths” as “T” and that of B, when taking the short path as “t.” Designate the time interval between launches or “Delay of the launch of B” as “D” and make D = T - t. Thus, when B takes the short path it will emerge from the interferometer (or strike the scintillation screen) simultaneously with A when taking the long path.* (When B takes the long path it will arrive at the screen D after A, but this is mentioned only for clarity and does not, I think, affect the argument being presented.).

    I will designate the “Pilot” or “Guiding” Wave of B, which will cause it to make (with many repetitions), two equally strong scintillation locations, as Wb and correspondingly Wa is the wave that causes A to form a single maximum scintillation location on the screen (with many repetitions).

    When A and B emerge at the same time and travel to the screen together each is guided by it own wave. That is Wa guides A to the single peak with out disturbing the trajectory of B while Wb guides B to its twin peaks without disturbing the trajectory of A to its single peak. That means that Wa can “recognized” A and distinguish it from B, (and conversely) and yet it is well established that all electrons are identical.

    The Pauli exclusion principle is based on electrons being identical, indistinguishable from one another (and fact electrons are Fermions, spin = ½). Thus it appear to me I must chose between Bohmian QM and the Pauli exclusion principle. If I were to choose B’s QM, much of physics would lose its foundation and all of chemistry would collapse as there would just be many different isotopes of one element not a Periodic Table of elements. Etc.

    Thus, reluctantly, I conclude, Bohmian QM can not be correct. If you think it is, where is the flaw in this argument against it?

    Thank you, Billy T.
    -------------------------------------------------------------------------------------------------------------------------
    *Or even when A is taking the "shortened path", if A has already past the region in which the path is shortened; however, as Wa may "feel" the shorting it is better to focus on the problem when A is taking the long path and B the short one. Even if this is only 25% of all events, it is still a problem for Bohm QM validity, I think.

    If due to the shorting, Wa “instantly” becomes identical to Wb, and only the "twin peak pattern" is produced by both A & B type reply is made, then allow A to emerge slightly prior to the shorting. I.e. the shorting occurs after A emerges and is on its way to the screen, but for less than D seconds, so B is still inside the interferometer when the shortening occurs.

    This “instantly” is of course subject to speed of light limitations so with even a slight “head start” out of the interferometer, a very fast A electron could be most of the way to the single peak screen location before the change in Wa caused by the “shorting” caught up to A. If A is near the single peak location, how (assuming both A & B make only the "twin peak pattern" is the type reply made) can A make the "twin peak pattern"?


    Note: The above text was posted in the www.sciforums.com “Math and Physics” forum’s thread “Quantum uncertainty vs. Determinism” on 28 June 2006 and earlier brief versions of this objection appeared in several other threads many months ago, all by “Billy T” whose real name is available to you if desired. See also www.DarkVisitor.com for direct contact email etc. or join forum and post responses.
     
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  7. c'est moi all is energy and entropy Registered Senior Member

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    Billy T,

    I think your argument is flawed for the reasons I gave above. Each electron is identical, and each of them has an identical charge as well. Now broaden that scope and see that each electron has an identical quantum field (wave) with it. Though the charge is a virtual field, the quantum field isn't and it follows the rules of the Schrödinger equation.

    "When A and B emerge at the same time and travel to the screen together each is guided by it own wave. That is Wa guides A to the single peak with out disturbing the trajectory of B while Wb guides B to its twin peaks without disturbing the trajectory of A to its single peak."

    I think they do disturb each other, depending on the state of the quantum potential.

    "That means that Wa can “recognized” A and distinguish it from B, (and conversely) and yet it is well established that all electrons are identical."

    "Recognition" is a key feature in physics. It's all about exchanging and recognising active information. If all electrons are identical, how do the virtual photons know where to be? They "feel" where to go, and they "know" which electron to surround? The fact that each partcile is guided by its quantum field, meaning that the two are in relation with each other, can hardly be used as an argument against it.

    And obviously, in Bohmian mechanics, particles ARE distinguishable due to the different paths that they follow (i.e. based on information). It doesn't matter if they are identical or not. That is the "hidden" variable, which does not exist in the orthodox interpretation.

    I hope somebody will answer you mail with a more sophisticated answer

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  8. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    The question is How. The pilot wave goes by all paths, "knows" about the entire interferometer system or is "present in all of it." Thus electron A is immersed in wave Wb but not affected by it. How? I.e. how can Wb distinguish electron A and guide it while ignoring electron B if there is no difference between the two electrons? I think you are just stated "Wb guides only B" and this is true, but not possible because Wb is surrounding electron A also and there is no way Wb can "know" which electron it is to guide, unless there is some difference between electrons.

    Thanks for your comments, and I too hope someone will point out a flaw that will persuade me that my argument is against Bohm's QM is wrong as philosophically his version of QM is much more satisfying to me (all humans?) but until the How? is answered you are just restating "it happens."
     
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  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    This is good question, one I am not very knowledgeable able about. "Virtual" has two different ideas with it.

    One is "virtual pair production" in the "vacuum polarization." E.G. electron and positron coming into existence from empty space, which is about 1Mev of new energy, a violation of conservation of energy permitted very briefly by the (delta E)(delta t) uncertainty of QM. I think that almost all of the time they mutually annihilate together, but think it possible that if a pre-existing electron is near-by, then the positron could kill the pre-existing electron instead. - I.e. I do not think the positron "knows' or can distinguish the electron it was "born" with from any other.

    The other "virtual" is the model of how electric forces and produce "action at a distance" in a vacuum. I.e. proton and electron exchange "virtual photons" as "carriers" of the electrostatic force. As the electron is attracting ALL near by protons, it is not distinguishing between them and conversely the proton cannot distinguish between near by electrons but attracts them all.

    Thus, no matter which type of "virtual" you were thinking of, it only seems to support and agree with fact that "All electrons are identical." However, Bohm's Wb must recognize the A is not to be guided and that B is to be guided even thought both A & B are immersed in wave WB. Again, how is this possible, if electrons are all identical?
     
    Last edited by a moderator: Jun 29, 2006
  10. c'est moi all is energy and entropy Registered Senior Member

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    Just a small reply to the "identically argument". A photon moving through vacuum can undergo a virtual transformation and become an electron-positron pair. Normally they will annihilate each other and again transform into a photon. What does this mean? Particles are "interexchangable" - like you exchange paper money for coins. The concept of "value" and "energy" seem very much the same for me. But the coin isn't physically the real value, it's a token representing its value. Likewise, particles are in a sense representations of a certain value, expressed in terms of energy. Therefore, it's logic that they can be exchanged for one another.
    So for me, and that is also what David Bohm is saying with his implicate order paradigm, we live in a world of expression, i.e. it is a token - and when taken to the more subtle level, you can speak of symbols. Particles are as real as money transactions, but you musn't forget the underlying mechanisms and potentialities that lie beneath it.
    Further, you wouldn't say that coins and papers are moving around in this world due to some Newtonian forces acting on it. It is primary because we people, have ideas in our heads with different goals, that make this money go around the globe. In fact, we are the analogy of the quantum potential, "guiding" the money around. I think since we are all very familiar with this phenomenon, we could agree that "guiding" would be quite misleading and inaccurate to describe what's going on. There wouldn't be anything moving at all without us, so we are a creative force.
    Now, we all like to view people as different entities, but if there's one thing we know about them, then it is the fact that when these "distinct" agents are in a group, they will exhibit quite predictable behaviour. Yet, do you see any "strings" between them that is causing this? The group behaviour is indefinite complex, yet predictable. And a person on its own behaves not only differently, it's behaviour is very hard to predict.
    Yet, in all this dynamic interaction between groups and individuals, money will flow along semi-predictable pathways, but always with that uncertainty involved. You wouldn't say that there must be a problem with this interaction between money and people, like "how do they know what money they own", or "how do they know which money to spend" etc.
    My whole point is, what makes you so certain that the quantum potentials acting on 'visible' particles are less complex than human beings and their economic behaviour? You are asking questions in a one-to-one relation with a very reductionistic and materialistic view in mind. I think that is a grand mistake.
    Opinions of the quantum formalism school expressed by Feynman et al, would want us to believe that "there are no internal mechanisms to be discovered no more". At the end of the 19th century, students were discouraged in following physics, because physics was thought to be near complete. Now, a mere century later, we are not expected to believe this, but instead, we are supposed to accept that our measurements are the only thing which counts (pure epistemological approach) without wondering if there might be something hidden which we can't see.
    Particles are most certainly an abstract form created by our measurements, and they could be much, much more subtle - in fact, they could have an inner cosmos. Pauli's exclusion principle basically explains nothing at all, it simply says that this kind of matter (fermions) tends to group in a ordered fashion, at discrete values. The idea of a quantum potential easily transcendents this kind of superficial physics, and I don't have the feeling that those continuing Bohm's work today realise its significance as profound as Bohm himself did. It very much demands a different world view, and you won't find that layed out in the maths.
     
  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I don't think you should let philosophical ideas cancel well known facts. For example, long before "us," long before the first multi-cellular organism, long before any form of life on Earth, the Earth was moving around the sun. Craters made by moving meteors etc were forming on many planets. Life need not exist, and probably does not on most planets yet those with atmospheres had and have weather fronts, storms etc. moving across their surfaces.

    It explains all of chemistry in the sense that with out it there would be no periodic table, only many isotopes of one element with each having progressively little chemical difference from the next lighter one. To mention only a few minor points: None of the noble gases could exist; oxygen, nitrogen, and carbon, thus no form of Earth life, could exist.

    You know too little quantum physics and I cannot teach it here, but will try to show bases for this Pauli effect on all of chemistry:

    The main quantized energy levels have designation n = 1, 2, 3,...
    The angular momentum is quantized also and usually designated by l = 0, 1, 2, or for historical spectroscopic reasons, before QM by l = s, p, d,...
    With the numeric value of l, the l < n must be true.
    The "projection" of l is also quantized and can have negative values. It is designated by m and |m| = or < l. For example, it l = 1 them m= 1,0,-1 are the only three possible values of m.
    In addition to these n, l, and m "quantum numbers," the intrinsic spin can be up or down (with respect to the axis of l and m) and I will just say spin quantum number S is u or d although this is not conventional.

    Now as more positive charge is added to the nucleus more electrons are in "orbit" about the nucleus to maintain the atom electrically neutral.

    The Pauli Exclusion Principle states that the quantum number set for the new atom must not be the same as any earlier or other electron. Hydrogen has A the Atomic number 1, Helium's A = 2 etc up thru the periodic table.

    Here is how the table is built up (I will not go thru all and it gets more complicated as the n = 4 level possibilities are not completely exhausted before the lowest n= 5 possibilities have lower energy than the next possible n = 4 ones. Also, I will not show the two S states, but u & d never make much energy difference so effective each level has double capacity of list below.

    A........n...l....m..............................Number of elements it Periodic Table row
    1&2.....1...0...0 (Hydrogen and Helium)...2 (With He this shell is full, or Noble gas)
    3&3.....2...0...0 (li & Be)4
    5 to10..2...1...1 or 0 or -1 (B,C,N,O,F& Ne) (With Ne this shell is full, Noble gas)
    Note that the n=2 & l=1 has three values of m, each with u or p spin os that gives 6 elements the two possibilities with n still 2 but l=0 gives two more ad thus a total of 8 elements are found in the second row of the Periodic Table.

    The 8 elements with A = 11 thru A = 18 repeat the quantum numbers pattern of the second row of the Periodic Table, except n = 3 to satisfy the Pauli requirement that none these 8 new electrons have the same set of quantum numbers as any of the 8 in the full second inner shell or the two of the full inter most shell. For example A= 11 is Sodium with one electron in the third or n =3 shell and Neon's 10 electrons inside that outer electron. Likewise Li (lithium) had one electron in the outer most, n = 2 shell and He's full n = 1 shell inside. For A = 18 (Argon) there are 18 electrons, 2 in the n=1 shell, 8 in the n =2 shell, and 10 in the n = 3 and EVERONE OF THESE 18 ELECTRONS HAS A UNIQUE SET OF THE QUANTUM NUMBERS, n,l,m,S because and only because of the Pauli exclusion principle.

    now n = 4 opens up the possibility that l = 3 and that inturn opens the possibility that m = 3,2,1,0,-1,-2,-3.

    The first two electrons to go into the n=4 level make K and Ca outside the filled n =3 shell of Argon and quite a few more follow this regular build up pattern but the energy levels are getting closer together as n increases and then at some point in the filling of the n = 4 the two n = 5 levels corresponding to K an Ca have a lower energy than continuing to fill the n = 4 shell. I think these two n = 5 lowest levels are Iron and Cobalt. If so, then Fe & Co would have an inter shell of "partially completed" n = 4 states, not the filled inter n = 3 shell inside the two outer electrons of K and Ca but as the outer shells are them most active chemically Fe will resemble K and Co resemble Ca chemically as their quantum numbers will correspond except for the n = 4 or 5 difference. (Pauli principle demands difference.)

    Thus Ca is:
    n = 4, l = 0, m = 0, u & d or two outer electrons around Argon electronic structure*, one spin up and other spin down, satisfying Pauli in this n =4 shell

    Mg (A=12) in the n = 3 shell also has l = 0, m = 0, u & d but Pauli is happy as n=3 and n=4 are different.

    Be (A = 4) in the n = 2 shell also has l = 0, m = 0, u & d but Pauli is happy as n= 2, n= 3 & n =4 are all are different.

    He (A = 2) in the n = 1 shell also has l = 0, m = 0, u & d but Pauli is happy as n = 1, n= 2, n = 3 & n = 4 are all are different.
    ----------------------------------
    * The "Argon electronic structure" is the 18 electrons possible without duplication of any quantum number set, AS PAULI DEMANDS:

    When n = 3, the angular momentum quantum number l can have three different values, 2,1 or 0. Thus:

    (l = 2 , m = 2)u or d for 2
    (l = 2 , m = 1)u or d for 2
    (l = 2 , m = 0)u or d for 2
    (l = 2 , m =-1)u or d for 2
    (l = 2 , m =-2)u or d for 2
    The above 10 must be in the n = 3 shell as l = 2 and QM requires that l < n.
    (l = 1 , m = 1)u or d for 2
    (l = 1 , m = 0)u or d for 2
    (l = 1 , m =-1)u or d for 2
    The above 6 must be in the n = 2 shell as l = 1 and QM requires that l < n.
    (l = 0 , m = 0)u or d for 2

    10 + 6 + 2 = 18

    i.e. Once an electron claims a possible set of quantum numbers all other electrons are excluded from that set = Pauli's exclusion principle.

    It has been a long time since I used the Pauli exclusion principle to build up the Periodic Table. I hope I have not said anything wrong, but even if I have, you should understand that your statement:

    "Pauli's exclusion principle basically explains nothing"

    is about as false as any statement I can think of. Pauli's exclusion principle is the reason why chemical elements exist (and all of chemistry as we know it), however it does much more than that, but I can not even illustrate that for you. (I also forget much of it, but Pauli also forces the wave functions of all fermions to be anti-symmetric and this also has far reaching consequences.) Surely life would be impossible if Pauli's principle were not true. Perhaps the only thing that would not be dramatically changed beyond all resemblance in the universe might be gravity, an possible EM waves, but I doubt even they would survive without Pauli exclusion principle as they are produced by acceleration of charged particles, usually electrons.
     
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  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    After exchanging 5 Emails with a member of the Bohm group (see my post of 6-28) I believe my challenge to Bohm's QM is very probably without merit.

    Basically because the wave function or "guiding" wave in Bohm's QM can guide electron A different from Electron B even though they are intrinsically indistinguishable by fact they are at different locations in the spatial extent of the wave function.

    To make my challenge stand, I must be albe to separate the wave function into two separate parts, one inside the interferometer, which obviously changes after A has emerged from it, and an external part that never changes, so when B emerges very short later, it is repeating exactly the dynamics of A.

    I have not been able to conceptually design such a static "outside" wave function part while shorting one of the two paths thru the interferometer by half a wavelength when A is already outside and B is still "inside." My basic problem, as I see it, is if there is a connection for the electrons to leave the interferometer, then there is also a way that some of the chage in the "inside" part of the wave function can "leak out" and make a change in the "outside" wave function also. Thus, the experimental fact that A & B form diffent patterns on the screen (when experiment is repeated many times) can not be used against Bohm's QM.

    I post this note to correct any impression I have may have given that I might have a disproof of Bohm's QM. I do not.
     
  13. c'est moi all is energy and entropy Registered Senior Member

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    I wasn't referring to that kind of meaning, but within the context of economics as an analogy.

    I did mean a different notion of the term "explanation". Pauli's exclusion principle does not tell us why there should be the exclusion in the first place. That's all I meant. Little did I know that you would go for the kill, so to speak, and focus entirely on that little sentence of my post

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    I'm glad your objection to bohmian mechanics was resolved in your mail exchange. I had the feeling that it would turn out alright

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  14. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    For that turn to a priest or a crackpot physicist, perhaps a foolish philosopher, but not to me.

    PS I too am glad my stone only bounced off Bohn's QM and I too though it would do that, but was courious to see just how it would fall away.
     
  15. c'est moi all is energy and entropy Registered Senior Member

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    I don't know if what I said is spelled out like that in set theory. Neither do I know why you should be offenced. If my logic is seriously flawed, you can also point it out without the aparent agitation.

    The exclusion principle defines a relation between electrons. It doesn't say why such a relation exists (I think). That's basically it. What could a priest tell me about that?
     

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