Skip to comments.Why Quantum Mechanics Is Not So Weird after All
Posted on 09/14/2006 10:27:24 PM PDT by snarks_when_bored
click here to read article
PH: please deploy your obligatory "Path of Least Action" ping list....
Fascinating post, snarks_when_bored!!! Thank you so much for posting it!
As Robert Nadeau and Menas Kafatos point out, [in The Non-local Universe], classical physics evolved in the framework of customary points of view and forms of perception, which are ultimately rooted in visualizable experience.
But neither the world of relativity nor the quantum world are visualizable in the standard sense of that word. Which is likely why we think phenomena at the quantum level are so weird.
[Niels] Bohr often emphasizes that our descriptive apparatus is dominated by the character of our visual experience and that the breakdown in the classical description of reality observed in relativistic and quantum phenomena occurs precisely because we are in these two regions moving out of the range of visualizable experience . [p. 90f]* E.g., this is not a clockwork universe!!!
[Quoting Bohr here] Just as relativity theory has taught us that the convenience of distinguishing sharply between space and time rests solely with the smallness of the velocities ordinarily met with compared with the speed of light, we learn from the quantum theory that the appropriateness of our visual space-time descriptions depends entirely on the small value of the quantum of action compared to the actions involved in ordinary sense perception .
Just as we can safely disregard the effects of the finiteness of light speed in most applications of classical dynamics on the macro level because the speed of light is so large that relativistic effects are negligible, so we can disregard the quantum of action on the micro level because its effects are so small. Yet everything we deal with on the macro level obeys the rules of relativity theory and quantum mechanics, and unrestricted classical determinism does not universally apply even in our dealings with macro-level systems.* Classical physics is a workable approximation that seems precise only because the largeness of the speed of light and the smallness of the quantum of action give rise to negligible effects.
Bohr always insisted, however, that the classical language of Newtonian mechanics must be used in describing quantum phenomena, in part for epistemological reasons based on the above observations. Plus he thought of quantum mechanics as a rational generalization of classical mechanics, and so the results of quantum mechanical experiments must be expressed in classical terms.
For Bohr, quantum mechanics is not an extension of classical mechanics. Instead, he viewed classical mechanics as a subset, or approximation that has a limited domain of validity, of a more general physical situation which is comprehensively described by QM.
This is totally amazing stuff!!! The categories of thought that arose in and were shaped by visualizable experience truly are no help here. We need a new way "to look at" the world.
Thanks again for this stimulating essay, snarks!
Statistics is a little unusual compared with ordinary kitchen variety calculus. There are a couple of leaps they make because of the form of the math. I suppose the leaps are okay so long as they seem to be working. They do solve that pesky calculus integral with the -e^2 in it, which most calculus books wave their chalk at and appeal to higher powers.
Maybe you should go hardaport for a while, and then Murphy would get to like you?
Britney certainly knows her density of states....
Feynman was an absolute master in his ability to look at things from many different directions, many different points of view.
True.. I'am here to serve d;-)~'.'.'.
There are two dimensions..
This one (length,width, depth and the illusion of time) call it the Maze of Physical Observation.. by the human brain according to time..
Another dimension composed of spiritual things.. God, Angels(two kinds) and US.. call it the Matrix of Spiritual Observation.. by the spirit of spiritual beings according to timing not time..
Two dimensions or paradigms.. existing parallethe Matrix of Spiritual Observationl to one another like two sides of a coin, reciprocals.. Mixing them up randomly makes mud... but addressing each in its own ugh!.... realm makes colors of thought.. And ultimately a mental/ideolological painting displaying a "painting/view/vista/homogeny".. Like when a two dimensional portrait/painting/landscape appears to be three dimensional but isn't.. Its two dimensional(the drawing) but shows shadows of something deeper than two dimensions..
If we(humans) are spirits riding a human body then both realms are/can be available to us.. And our "observations" should be of "the coin" not one side or the other.. Observing from the Maze of Physical Observation then is flawed(science) or from the Matrix of Spiritual Observation is flawed(religion) just the same..
I agree we need a new way to look at things..
Wonderful as usual, Betty. Thanks.
Sharp as a tack, that one
Do quantum mechanics use quantum wrenches?...........
Point 2) under "conceptual problems" was especially important, IMO. People who read about quantum entanglement often misconstrue this point (even some otherwise very good physicists I've known).
There are two dimensions we experience on a comprehensive scale, dimension time and dimension space. We also experience the dimension of life force because we are alive and sensing, and the dimension of spirit because we have a sense of good and evil (well, most people do anyway).
Here's a different way to consider these dimensional aspects. Each dimension has three variable expressions. With dimension space we have linear, planar, and volumetric, with time we have past , present, and future, corresponding roughly in conception to the three variable expressions of dimension space. With dimension life force we have will, emotion, and mind --for want of better terms-- and these also have a similitude to dimensions time and space. I suspect there are three variable expressions to dimension spirit also, but I haven't a clue yet what the variable expressions might be called.
Here's a though regarding the mixing of dimensions time and space. In classical physics there are distances at which the various standard model forces are in effect for the phenomena 'observed'; I would switch this way of describing that, to say that the various forces act in various spatial expressions, as in planar or volumetric, for instance. There may be (and I believe firmly that this is the actual case) 'times' at which the various forces are in effect also, mingled with the various distances (spatial characteristic).
I am working on a paradigm to explain this different perspective using space/time realms or continua as the limits for the various forces. As an example, gravity is a volumetric/past phenomenon, where the temporal aspect is the operant in the force expression, so the entire universe is the realm of gravity action based upon an entanglement of temporal origin related to the start of the disunity to dimension time at the big bang origin of our universe.
Dimensions life force and spirit have been added to the mix of dimensions space and time, broken into constituent expressions, and until some means of mathematically expressing the combinatorial nature of their being mixed into the universe is found, life and spirit will remain metaphysical realms of wonderment, while space and time will continue being explored and codified using a touch of metaphysical perspective, as in quantum field as 'aether' (in a spatio-temporal sense) for standard model force expressions, and entanglement, and action at a distance (each area of exploration being dependent more upon a temporal or spatial expression for fundamental interaction of matter and energy).
Because of this 'different' way of viewing the universe and the standard model for subatomic reality, I have predicted that no graviton particle will be found as mediator of the force of gravity, because gravity is primarily a temporal phenomenon not a spatial phenomenon. Electromagnetic effects are primarily spatial phenomena thus a mediating particle acts as focus of the force exchange because everything in this universe is entangled via temporal containment (everything is existing within a temporal volume in relation to everything else) ... we are in the universe we are in and in which the processes that have resulted in us have occurred, adding dimensional expressions as we have been 'built up' in complexity.
Other 'beings', such as angels, may not have been 'built' in the same fashion from the simplest to the more complex as we have been constructed, for the mind of God can bring things into being by a word, at any complexity level He chooses to assume for them. Parallel universe theory and brane theory and string theory are all hinting at a more inclusive way to define the universe. I think there are recorded examples of events where greater complexity realities have intersected our reality, as in Daniel chptr 5, and the entire of Jesus sojourn on this planet.
Hope this hasn't been too esoteric to have meaning for you.
What we need is a magazine called "Popular Quantum Mechanics."
The assault on the Copenhagen Interpretation continues.
I don't think that's true. GPS positioning uses a leading order correction based on General Relativity to compensate their positioning. Without it the satellites would lose several meters of accuracy every day.
Ping for later
Adrian Schwinger (at least as much a big dog physics guy as Feynman was) believed Feynman's view of quantum mechanics to be fundamentally flawed. It has to do with reconciling Maxwell's equations with quantum theory.
If Feynman is correct I read that quantum computation is possible, and, if not, is not.
The Schwinger-Tomonaga operator-theoretic approach to quantum electrodynamics was shown to be equivalent to the Feynman sum-over-histories approach by none other than Freeman Dyson (an act which secured Dyson a permanent faculty appointment at the Institute for Advanced Studies).
(N.B.: When I say "problems", I don't mean mathematical inconsistencies in the theory or disagreements between the theory and experimental fact--we know of none--but rather refutations of our naive philosophical expectations.)
For example, with Schrödinger's Cat, he shrugs and says, "QM can't predict the future, no problem". But the problem isn't a question of the future; it's a question of the past.
Suppose the decision whether to release the prussic acid occurs at 4:00, and the chamber is opened at 5:00. The cat is in a superposed dead/alive state at 4:30. It will collapse at 5:00 into one state or the other, sure, but that doesn't mean the cat will live or die at 5:00. The death of the cat, if death is the outcome, will have occurred at 4:00. At 4:30, that event is already in the past. At 5:00, when the mixed state collapses into the death eigenstate, the cat will be an hour dead. It's not the future which is indeterminate, but the past.
Furthermore, the author misleads when he says "we never see this". We may not see it with cats in our sadistic basement experiments, but we see it in the lab, with subatomic particles. Indeed, we exploit it as an experimental tool.
I thought you might get a kick out of this - I think I'm going to enjoy pondering it quite a bit.
But if quantum mechanics can accurately describe all the information we can ever obtain about the outside world, perhaps we are simply being greedy to ask for anything more. The headline "Physics Fails to Describe Events That Cannot Be Observed" is, again, rather lacking in impact.
Puzzles about superposition strike me as being modern instantiations of the problem of the one and the many. If I had more time (and were much, much smarter), I'd say more.
It does have esoteric and exoteric meaning to me.. Linear, planar and volumn (and time too) might be a 2nd reality.. Probably is.. It could be that "shape" is a 2nd reality.. i.e. all geometry really; including known physics.. Could be that EVERY human is "into" some version of 2nd reality..
Matter/energy (both light and dark energy/matter) could be plasmic in essence.. Like a very good painting/landscape(2 dimensions masking three) can look very real in this paradigm.. Its NOT real(the landscape) but appears to be real.. i.e. a created observation by a human.. This universe could be the same on a spiritual level(God).. except upped a level of reality..
I say that; to posit, that "shape" may be a human observational limitation.. meaning all matter/energy is plasmic.. in essence.. Shape being needed by human eyes and other senses in a limited reality..
This subject is quite deep.. and completely "out of the box"... So I don't discuss this with many.. Everyone I know cannot concieve of a universe without "shape" being integral..
Some people have problems with a tripartite God.. I do not.. It could be God is an amalgam of additional(not mentioned in the bible) Spirits also.. i.e. Father, Son, Holy Spirit plus additional entities not mentioned.. or not.. One way or the other "that" would have no bearing on the bibles message(s) anyway.. Father, Son, Holy Spirit is fine with me..
Some of Stephen Barrs ideas have serious merit...
Dean Koontz wrote a good book called "From The Corner Of His Eye" that involved quantum mechanics. Dean gets into some detail about it as he really does his background research when writing books. I would highly recommend this book for entertainment value as well as a for a little quantum mechanics knowledge.
That would depend on how much mathematics is in one's "standard sense."
In the Copenhagen Interpretation, QM only represents our state of knowledge of a system. With the cat hidden in the box, QM only predicts the probability of what we will find when we open it.
Suppose we put a clock in the box instead of a cat, rigged to stop when the quantum event is detected. When we open the box we will find it running or stopped, and in the latter case we may certainly say that the time it records is the time of the quantum event.
Note that even a dead cat is an evolving system, and we may say by various means such as temperature when it died, even if we weren't watching. The cat is no different than a clock in this way.
This famous paradigm is more a rhetorical exercise than philosophical. The characterizations of "dead" and "alive" as quantum states is entirely unjustified, but the drama of the situation distracts us from noticing.
This is certainly a different interpretation than was adopted at Copenhagen. What the Germans said was that the cat is neither alive nor dead until we make an observation of it. Schroedinger's equation allows us to calculate the probability of what we'll find when we make the observation.
Quantum Mechanics: The Dreams Stuff Is Made Of
You're wrong. It's a statement about reality.
You're being distracted by the fact that in the case of a cat, the "dead" state does not interfere with the "alive" state. But in the real world, the superposition is one of simultaneous realities and not simply a statement about our ignorance of the state of the system.
Two examples that spring immediately to mind are double-slit diffraction and the Bohm-Aharonov experiment. In each case, there's a measurable interference term caused by the simultaneous realities.
In the case of double-slit diffraction, you get an interference pattern caused by the simultaneous superposition of Schrödinger waves from each slit, which is very different from a mere sum of wave amplitudes from two individual slit sources.
Let's be more specific. Suppose we label one slit the "left" slit and the other the "right" slit. We project electrons through the slits and towards a screen, but we don't know much about their exact trajectories. Classically, they might go through one slit or the other. Quantum mechanically, the wave function is a superposition of the state where it goes through the left slit AND the state where it goes through the right slit.
If the superposition were merely a statement of our ignorance, our mere knowledge of whether each electron went through the left slit ("alive", if you prefer) or the right slit ("dead", if you prefer) wouldn't affect the final distribution of electrons from the slits when projected onto the screen. But the experimental reality--and the mathematical prediction--is that that knowledge matters a great deal. If we add up the cases where we remain in ignorance, we see a series of light and dark bands on the screen: interference fringes. If we add up the cases where we know which path the electron took, we see the sum of two Gaussians. No fringes.
Quantum mechanically, what is happening is that, by knowing the trajectories, we are collapsing the electron trajectory eigenstates into either "left" or "right". The interference between the slits then disappears; it's as if the slit not used were simply covered up. Classically, there is no analogue.
Now, you might think that perhaps the interference effect has nothing to do with individual wave functions or trajectories. Perhaps if you get a cloud of electrons flying through two slits, they'll bounce off each other, block each other, and knock one another to this or that side in such a way as to produce the interference fringes, even though each individual electron took a definite, well-defined path through one slit or the other. But that's not the case: the interference effect works even if we send the electrons through one at a time, so that each electron can't have any contact or "knowledge" of the rest of the ensemble. Any simple interpretation will have to say that each electron went through both slits, taking both paths simultaneously.
The Aharonov-Bohm experiment is more technical, but it involves two (field-free!!) paths around a magnetic solenoid, and the shifting of interference fringes as the field within the solenoid is altered. The principle is one of gauge symmetry: there's a phase angle associated with the difference in integrated vector potential along each path.
OK, that was a mouthful, but the key is this: BOTH paths have to contribute simultaneously for each electron, or the effect disappears. It cannot be said that each electron passed either to the right or left of the solenoid.
I'm giving special heed to Bohr's remarks. Wikipedia notes that one can speak of the "collpase", or simply say that the theory makes predictions without granting any kind of physical reality to wavefunctions ( or propagators. )
"Niels Bohr emphasized that it is only the results of the experiments that should be predicted, and therefore the additional questions are not scientific but rather philosophical."
Taking this lead, I've always seen the CI as the "bare bones" interpretation, which contents itself with the predictions made using the theory. Bohr emphasized that we are constrained to speak and understand in everyday terms, and the theory itself is part of our everyday experience of pencils and paper and apparatus.
Even allowing that the condition of the cat is "undefined", we can take this to mean it is undefined by the theory, which is plain to see since its predictions are probabilistic. To put any more into it is mere mystification, as I see it, and I believe I'm following Bohr in this.
... and yet! ... and yet! One can never be very happy with this view, can one? The mystery of QM is ineluctable.
I would also comment that I put a lot of weight on Feynman's remarks on neutron scattering in a crystal in his Lectures Vol. III, 3-3. He contrasts the case of no-spin-interaction, where the scattering nucleus is indeterminate, with the spin-interaction case, where a particular nucleus is affected by the scattering. Thus the crystal itself "observes" the scattering, and localizes the interaction.
"You may argue, 'I don't care which atom is up.' Perhaps you don't, but nature knows; ..."
This obviates the question of an "observer", since after all why may not the cat be regarded as an observer, or what if we put a physicist in there? Or for that matter a clock, or any kind of recording instrument?
I'm not very intelligent, but does communication play a role in all of this stuff? And, I don't mean what you stated in your posts, but the whole of this quantum stuff.
Something (the sender) must tell something else (receiver) to behave or do something. The message sent must both be efficient, in the sense that is received correctly and understood, and effective, in the sense that the response of the receiver is the desired response of the sender.
A paragraph with some relevance to the point you were making:
"Schwinger learned from his competitors, particularly Feynman and Dyson. Just as Feynman had borrowed the idea from Schwinger that henceforward would go by the name of Feynman parameters, Schwinger recognized that the systematic approach of Dyson-Feynman was superior in higher orders. So by 1949 he replaced the Tomonaga-Schwinger approach by a much more powerful engine, the quantum action principle. This was a logical outgrowth of the formulation of Dirac , as was Feynmans path integrals; the latter was an integral approach, Schwingers a differential. The formal solution of Schwingers differential equations was Feynmans functional integral; yet while the latter was ill-defined, the former could be given a precise meaning, and for example, required the introduction of fermionic variables, which initially gave Feynman some difficulty. It may be fair to say, at the beginning of the new millennium, that while the path integral formulation of quantum field theory receives all the press, the most precise exegesis of field theory is provided by the functional differential equations of Schwinger resulting from his action principle."
The "sending and receiving" stuff that you see in regards to quantum entanglement experiments is heuristic, or philosophical, or whatever. It is definitely not part of Quantum Mechanics!
A striking feature of QM is what Heisenberg called "quantum kinematics". That is, the framework of the theory itself. Many of its amazingly numerous and varied results stem directly from the workings of this framework, and this includes entanglement, degeneracy pressure, and quantum levels themselves, not to mention Light Amplification by Stimulated Emission of Radiation.
Of course, the theory cannot offer any explanation of its own framework, yet traditional heuristics offer many such quasi-classical, and even anthropomorphic explanations. I try to ignore these as much as possible, but you can't get away from them. Note that the term, "stimulated", in the acronym LASER, is just such a heuristic. The laser phenomenon is a pure implication of quantum statistics, and does not involve any sort of postulated "stimulation".
This stuff is hard for the layperson, but extremely interesting. It's like the more I read, the more I understand how much I didn't know.
"You were not made to live like brutes, but to follow virtue and knowledge." - Dante
Wonderful words, dear Pipe. Thank you so much for including me in the ping to them.
Very true. I'm so glad we can share such things in Christ!
LoL.... !Quite funny until the reality of it is considered...
Fascinating. For a layman, I would love to be able to read something that will delve further into this. Got any specific links?
ping for later reading
You know, this is about as far as it goes for laymen until they start digging into the math. But, if you do that you will be doing the real stuff. These made-up examples aren't of much use except to point out that they are mostly nonsense pointing the way to the actual physics. The math isn't really all that bad once you take that step.
Too many people believe that quantum "weirdness" opens a window for the paranormal, supernatural, mystical uncertainty, etc. when in reality, it makes specific physical predictions with a rigor and accuracy unparalleled by any other scientific theory.
The cat was pregnant.
"Any simple interpretation will have to say that each electron went through both slits, taking both paths simultaneously."
Maybe the electron simply swallowed the grid and spit it back out when finished.