I wonder if an agent, or the act of observation, is kind of like causing a nucleation site to form, thereby allowing the "crystallization", or formation, of the state of affairs (e.g., what is observed) to proceed. What I'm thinking is as follows. Let's say that reality is made of little, jiggling membranes. One might call these strings, loops, or whatever. They have the potential to cause the formation of other membranes around them. This potential is what is called quantum probability. But, while the membranes are jiggling, there's no stable, unmoving surface that can serve as a nucleation site for this potential, or quantum probability, to collapse and cause the formation of the new surrounding membranes. This means, then, that the act of observation by an agent is just the ability to temporarily stop the jiggling of a membrane, thereby allowing a stable surface to be present and act as a nucleation site to allow the surrounding quantum probability to "crystallize", or collapse, and causing the formation of the new surrounding membranes and the appearance of the observer-caused state of affairs.

Just an idea I've been working on based on my own thinking. Thanks.

"Steinberg's work on measurement, information-storage and erasure is intimately tied to a fundamental theorem of quantum physics that says quantum information can't be perfectly copied."

In Shannon's Information Theory, any data or state that cannot be perfectly copied, is not information in the first place; When a system contains both "signal" and "noise", only the signal (AKA information) can be perfectly copied - that is the defining property of "information". Quantum states cannot be copied, precisely because they contain a great deal of noise, and not just signal; a single bit of information (like spin-up or spin-down) cannot exist without noise being present, since reducing the noise will necessarily enable more than a single bit to be detected.

Rob McEachern

Regarding the quantum measurement process in 'interferometer experiments' where 'photons are made to travel along different paths', as I understand it there's a photon emitter (laser) and a receiver (such as a photosensitive plate), and some measurable distance between them as part of the whole laboratory setup. This is the observer's lab world and for them there is an actual fact of the matter concerning a measurable quantum of energy being emitted, and the same quantum of energy being received, as well as a measurable duration between these two events relative to that observer's frame of reference in their lab world.

But then, in the space between the emitter and receiver there is no fact of the matter concerning what it is that apparently travels between them. The wave function describing the possibility of measuring certain properties at any point along the way is as much as we can say about the physical reality of the photon. In this sense one might say that there are no actual photons, particles or waves, that 'travel along different paths' in the observer's lab space--there are only potential observations. And this wave function derived potentiality simply is the physical reality of the photon, at least for a wave function realist.

So ... at the point of measurement / reception / observation / decoherence, there are potentially 'many paths' a photon may have taken, which also means there are many potential pasts just prior to measurement. As far as I can see, these potential pasts are of the same physical reality as their potential photon, and that is a wave function reality. So there is no fact of the matter concerning their physical reality as an 'actual past path' until a photon is received, at which point the observer observes a 'past path' relative to their present (decoherent / branching) observations, whether that involves an actual interference pattern or not. Presumably, indirect measurements will rule out certain pasts and so constrain the potential outcomes.

I'm not sure this particular form of wave function realism allows for any sense of physical realism where an actual discrete physical thing travels across the lab space, or indeed any fundamental notion of an external classical spacetime. There are also wider metaphysical implications concerning how we might understand the difference between our actual observed reality and the wider realm of potential realities it constantly draws from, and specifically the reality of a single actual past as opposed to a present reality of many potential pasts. Agency in this sense, would be the present ability to choose the past appropriate to your immediate future!

Anyways, just an itinerant philosopher's thoughts on the matter.

    Malcolm,

    I live in a community in which every path (street) is a dead-end or cul-de-sac. There is only one way out. Hence, to catch (detect) a burglar trying to flee the community in a vehicle, the police do not have to send police cars to search out every possible path through the community; it is sufficient to simply put one detector at the only exit. All roads lead to that exist, eventually. Hence, any mathematical description (wavefunction) of such a detection process, need not concern itself with any paths-taken at all. It only needs to describe what happens (like the detection probability) at the site of those actual detectors. That is all that quantum theory actually does; assuming that it does anything else, such as "summing over all the possible paths" between the home that was burglarized and the exit, is not necessary - it is merely sufficient.

    Indeed, given that wavefunctions were first introduced into QM as Fourier transforms, it is interesting to note that Fast Fourier Transform algorithms, were eventually developed, by exploiting the fact that the vast majority of all the computational "paths" through the transform, will always sum identically to zero (cancel out), independent of the input; so there is never any reason to ever bother computing the entire superposition in the first place, if all you want to know, is the final result - at a particular detection site. In other words, instead of thinking of the process as having to sum a vast superposition over all the possible paths, it is much better to think of it as only describing the actual (non-zero) output at a set of detectors - an energy detecting filter bank; the agent, is just the detector itself. How well the police can detect/recognize the burglar at that exit, is entirely independent of the path that the burglar took to arrive at the exit. Similarly, the burglar's immediate future (as well as everyone else, unlucky enough to arrive at that police stop-and-search site) is quite independent of whatever past happened to bring them to that particular detection site, at that particular time.

    Rob McEachern

    @Rob, are you suggesting that photons objectively travel across the lab space as individual physical entities like a thief in a cul-de-sac?

    This sort of classical simile for quantum realities is precisely the question isn't it?

    Malcolm,

    I am not merely suggesting it, I am attempting to point-out that the actual facts demand it. Photons travel like phonemes in a sound wave; a distinct, recognizable entity, but one that is only detectable/recognizable, to another entity that knows, a priori, how to properly detect it, in its entirety - all or nothing - just like identifying and catching an actual burglar.

    But before you ask me about interference patterns, ask yourself, what insufficient argument ever induced you to believe that such patterns are only caused by interfering waves? It is known, for a fact, that if you merely compute the power spectrum of the Fourier transform of a two-slit (or any other number of slits) geometry, you will obtain the same pattern; So such patterns obviously have nothing to do with physics at all - no waves, or particles, or anything else, need ever travel though any slits, in order to produce such a pattern - because, it is a purely mathematical property of the information content, of the geometry itself, having nothing directly to do with physics, either classical or quantum. In other words, by mistakenly assuming that the information content of such patterns must originate as a property of the things (like waves) passing through the slits, rather than as a mere property of the slits themselves, the true source of the information (and thus the underlying cause for the pattern) has been entirely misinterpreted, just like misinterpreting a sound, as originating from a ventriloquist's dummy, rather than originating from the ventriloquist. Such phenomenon only seem "weird", because the true source (cause) of the information, is being misassociated, with the wrong, causal agent. There are no "quantum agents" in reality. Quantum agents only exist within the minds of physicists, that have come to believe in information-sparse "talking dummies", as information-originating agents, while totally ignoring the nearby, information-packed ventriloquist - the real agent responsible for causing the seemingly weird phenomenon at hand.

    Rob McEachern

    There are at least the following arguments against generalizing Fourier transform:

    - It might be convenient to calculate as if there was no causality.

    - However, if one doesn't ignore the reasonable causal distinction between past and future in objective reality, then one has to use Heaviside's virtual split into even and odd components.

    - Fourier transformation is then obviously redundant and therefore sometimes misleading.

    See my current essay.

    Eckard Blumschein

    Eckard,

    I would argue that all symbolic representation (and thus all of mathematical physics) is "sometimes misleading", when one has misinterpreted, what is actually being represented. In other words, it is not just the "redundant" nature of a Fourier transform that causes the problem, but that mathematical identities can always be used to rearrange and thereby "simplify" any such complicated expression, and thereby produce a very different representation (which nevertheless will produce the identical end result, to any actual computation) that may enable an entirely different interpretation than the original representation. In other words, the actual algorithm used to "simplify" an equation, and not just the equation itself, has a direct, causal effect upon any physical interpretation, regarding exactly what an equation is supposed to be "representing" in the real world.

    Rob McEachern

    9 days later

    Robert and Malcom,

    See me itinerant and a bit worried by Feynman's utterance on the impossibility to understand quantum physics. I understand your notion "many potential pasts" as many more or less irrelevant guesses of what possibly happened.

    I agree with Shannon on that the past is closed for good. It cannot be influenced, no matter to what extent it is known to us via direct memory, records, or interpretation of traces. Having found out an obviously overlooked mistake by Fourier that may affect some very basics of physics, I am nonetheless not yet in position to judge and derive all consequences.

    I merely wonder why there are still rather different pictures by Heisenberg, Schrödinger, and Dirac? Why can so far nobody refute McEathern's criticism of Bell's theorem? Given Einstein's theory of relativity, quantum theory, and chaos theory contradict each other for decades, I do not expect that a convincing unification will be found and confirmed. I don't hide that I disagree with deniers of causality.

    Eckard

    2 months later

    If thevunivrse is a close or open system this is out of the humanity competence. We cannot say any pros or disprove the possibility of quantum or black hole or other imaginary opportunities that can link the multiverse as a union. But we can take the assumption of the closed universe for the benefit of some theory solving the unknown. What does your respected and solid theory tends to solve as a physical or philosophical task. That is a question that is quite interesting.

      Hello,

      We have indeed many limitations due to our level of knowledges, we know so few still. What are the foundamental mathematical and physical objects ? what is the real universal philosophy creating these topologies, geometries. matters and fields inside this physicality. How the energy matters transformations act reall ? We have still many unknowns to discover and it is a big puzzle. I have a model , correlated with my theory of spherisation , an optimisation evolution of the universal sphere or future sphere and coded 3D quantum spheres and cosmological spheres , I consider a closed evolutive universe but can we affirm ? no we must accept our limitations and assumptions, we cannot affirm these assumptions respecting a deterministic logic.

      Regards

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