Everything is a quantum wave?

Science 4 Minutes

In the last post, I discussed Amanda Gefter’s critique of Vlatko Vedral’s view that observers have no special role in reality. Conveniently, Vedral published an article at IAI discussing his view: Everything in the universe is a quantum wave. (Warning: possible paywall.) Vedral puts his view forward as a radical new interpretation of quantum mechanics.

As a quick reminder, the central mystery of quantum mechanics is that quantum particles seem to act like waves, including portions of the wave interfering with itself, but when measured, behave like tiny localized balls. This is known as the measurement problem.

There are numerous interpretations of what’s happening here. But they seem to take one of three broad strategies. The first simply rejects that the waves are real, instead insisting that they are only probabilities, albeit probabilities which evolve deterministically and interfere with each other. In other words, it’s all happening in our mind. In its stronger incarnations, this has idealist or semi-idealist aspects, claiming that observation or interaction creates reality. These are the approaches in the epistemic versions of the Copenhagen Interpretation and its descendants, like QBism and RQM (relational quantum mechanics).

The second strategy is to add new structure to wave mechanics. Due to Bell’s theorem, these additions must be non-local in nature, that is, they must involve “spooky” action at a distance. The ontic version of Copenhagen takes this approach when it adds a physical collapse, as do its variations and descendants like consciousness-causing-the-collapse and other objective collapse theories. Another version of the second strategy is what are historically called “hidden variable” approaches, like Bohmian Mechanics (pilot-wave theory), where there is both a wave and a particle the entire time, with the wave guiding the particle.

The third strategy is to accept the mathematical structure of quantum theory as a full account, or one only requiring a few ancillary assumptions. This became easier with the development of decoherence theory in the 1970s, an extrapolation of quantum wave mechanics, in essence quantum entanglement en masse, that explains why quantum interference disappears at larger scales. It’s the approach Hugh Everett proposed, which eventually became known as the many-worlds interpretation.

And it’s the strategy Vedral uses for his interpretation, which he characterizes as “many-worlds on steroids.” Although he dislikes talking in terms of other worlds, noting that the classical worlds are only a small slice of the possibilities. He prefers to talk in terms of one world but with quantum mechanics being universal, applying at all scales.

Vedral makes a point I made in the last post, that under this universal quantum waves approach, an observation is just two quantum systems becoming entangled, that is, becoming correlated in certain ways. A reminder: entanglement is when two quantum systems have each of their states in superposition become correlated with each of the states in the other system. In other words, for each state in the first system, there is a correlated state in the second. The two systems are now part of the same wave function.

Vedral notes this could be characterized as the quantum particle observing the measuring device as much as the device is observing it. In this view, entanglement is what the apparent collapse looks like from the outside, and collapse is what entanglement looks like from the inside. So contra Gefter’s stance, there’s no special role for observers, at least unless by “observer” we mean everything.

As I noted in the last post, I like Vedral’s approach here of focusing on the physics rather than getting into multiverse language, which as I’ve noted before, often ends up being a distraction. But it’s hard for me to see how his view is radically different from the standard Everettian one. It’s worth noting that Everett’s original proposal was a theory of the universal wave function, essentially the “everything is a quantum wave” view Vedral is advocating. Everett didn’t talk in terms of a multiverse. It was Bryce DeWitt in the 1970s who characterized that way, although Everett saw it as just an alternate way of describing his view.

One difference from contemporary many-worlds views, which Vedral shares with Everett, is that the quantum nature of macroscopic objects is not beyond testability. Everett reportedly maintained that the quantum states of macroscopic objects were in principle detectable. I haven’t read Vedral’s book, but it sounds like a large part of it is finding ways to test his view.

This seems resonant with the progress being made in experimental research, where tiny macroscopic objects can now be held in a quantum superposition, which is putting increasing pressure on ontic collapse theories. And Vedral mentions the ongoing efforts in quantum computing, which is stress-testing quantum theory in ways scientists of earlier decades could only dream of. In the end, we need data, and these efforts are providing more of it.

As a minimalist Everettian myself, I find a lot in Vedral’s discussion compelling. But as he notes in his article, the various interpretation camps are like entrenched armies in World War I, unlikely to be moved except by the strongest experimental results. Even then, I suspect Max Planck’s observation that science moves forward “one funeral at a time” will likely be true here as it always has.

What do you think of Vedral’s views? Does the idea of everything being a quantum wave make sense? Or are there difficulties both he and I are overlooking with this approach?

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29 thoughts on “Everything is a quantum wave?”

  1. @selfawarepatterns.com A quantum wave! Why not a quantum brick or bubble? Confounding the logic of mechanistic, experimental, and abstract mathematical presuppositions with cognition is like severing the concept of the analogue or digital mind from its being. An ineffable or effable extreme is just a wall without a ladder. #AbstractER #Dichotomies

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    2. @Dialectician @selfawarepatterns.com Looks like my reply from the blog didn't propagate. Apologies if this end up being a double post

      The waves come from observations, like those in the double-slit experiment.
      https://www.youtube.com/watch?v=A9tKncAdlHQ

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      1. @selfawarepatterns @selfawarepatterns.com So bricks and bubbles don’t make waves? There is a long history of analysis on causality, but experimental thinking buttressed by Humean sentiments chooses to ignore the stronger reasoning of proof by inference. Quantum Electrical Interactions require a concept free from the spurious uniformity of expectations; abstract mathematics is not the foundation of the categories that constitute the science of logic.

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  2. Re “There are numerous interpretations of what’s happening here. But they seem to take one of three broad strategies. The first simply rejects that the waves are real, instead insisting that they are only probabilities, albeit probabilities which evolve deterministically and interfere with each other.”

    What many people forget is that Schrödinger’s wave mechanics had a competitor, matrix mechanics. Schrödinger eventually proved that the two forms of quantum mechanics were equivalent and since the math was easier using wave mechanics, that won out.

    What many people also skip over is that the sinusoidal wave functions of Schrödinger’s mechanics need to be squared to generate probabilities, so the wave functions actually represent square roots of probabilities, not probabilities themselves.

    So, if the “waves” are real, what the fuck they are is quite beyond me. And why aren’t people also claiming the matrices to be real, since they are equivalent?

    (I actually had to learn a bit of matrix mechanics back in school in the past century.)

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    1. I’d say they’re both real, in the sense of describing the same reality in different ways, along with Feynman’s path integrals.

      As to what they are, well, in terms of the theory, we can view them as waves of different versions of the particle, or the particle as fragments of the wave. But beyond that, are they substance, relations between substances, or something else? The complex numbers incline me to think relations, but who knows? I suspect if/when we find out, it will be in terms of new mysteries.

      I never took physics and so never had to learn matrix mechanics, although I did have to learn matrices themselves in one of my math courses. It’s kind of interesting that Heisenberg had never heard of matrices when he was working on his theory, so he ended up re-inventing them, only informed about what he’d done after the fact.

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  3. It was Vedral’s editor who characterized his theory as “Many Worlds on steroids.” Vedral writes that “there’s a grain of truth in that,” but his vision seems to be a different one. He begins with Heisenberg’s finding that a matrix-table of values gives a better description of a quantum entities than either a “point-particle” or “classical-wave” description. But where Schrodinger described the whole package as a quantum wave, Vedral seems to be suggesting that each value in the table varies in a wave-like way. At very small scales, the entities that arise from the matrix-level wave interferences are still capable of exhibiting wavelike behaviour; thus an entity can interfere with itself, or with other collections of matrix-table waves. The interferences give rise to classical particles, and ultimately to the classical world.

    Admittedly that’s reading a lot into what he says, but it would be my takeaway. Where it resembles Many Worlds is in the idea that quantum waves alone are sufficient to constitute reality, without the need for hidden variables or classical observers. I suppose one could extrapolate that the matrix-table interferences are realized in all their possibilities, which would indeed be Many Worlds on steroids. Vedral does not take his theory in this direction. Alternatively, we could suppose that the matrix-table interferences instead resolve into a single particle in a single world, but he seems to reject the whole idea of “resolving,” which assumes that we still need to get from quantum to classical physics. Vedral’s theory tries to do away with the need for classical physics as a theoretical construct. He says, “I am suggesting that we purge physics of all classical notions. This is why I think that the Many Worlds Interpretation is insufficient, as the notion of a world itself is also a relic of classical physics. It’s more appropriate to say that there is only one world, but that it is quantum through and through.”

    As is so often the case, Vedral ascribes more metaphysical significance to “observers” than is strictly necessary. Speaking loosely, he allows that “Entanglement is a completely symmetric property of entangled systems and the observers and the observed can swap places without any consequences: an atom is as much observing us as we are observing the atom.” But that doesn’t mean he’s gone all panpsychic on us. To his unreconstructed way of thinking, an observer seems to be the sort of thing that wears a lab coat. Regarding the notion that such things create reality with their minds, the less said the better. Here I think Gefter’s critique is exactly on point.

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    1. I think it’s worth mentioning that Vedral isn’t proposing any changes to the quantum formalism, at least not that I detected, so he’s not adding anything that wasn’t there before. Although I suppose he might be calling attention to aspects that maybe have been understudied. I have his book, which I hope to read at some point.

      I didn’t take him to be evoking any form of panpsychism with his remark about the particle observing the measuring device. I think he’s just saying there’s nothing special about the systems we usually label “observer,” at least at the level of quantum mechanics. That said, if panpsychism is true, and observers are important, then it seems like his view and Gefter’s would be effectively reconciled.

      There’s an old joke that was made in the early years of quantum theory, I think by either Einstein or Schrodinger, asking what was necessary for an observation. Was a bacterium sufficient? Or was a PhD required? A lot of physicists are pretty loose with the “observer” term.

      Vedral does link to Hammeroff’s IAI article toward the end of his article, commenting that some people were speculating that consciousness requires QM. But I think he was just being inclusive, since, as I understand it, adopting Orch-OR means adopting Penrose’s interpretation of QM.

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  4. My last comment on your previous post I’ll repeat:

    We probably should be a good deal more cautious about extrapolating QM to reality in general either with multiverses or conscious observers thinking reality into existence. It could be QM provides major clues to how reality works at the microlevel but the reality we experience is the world of ordinary measurement.

    “quantum states of macroscopic objects were in principle detectable”

    If you extrapolate to its ultimate “everything is a quantum wave,” doesn’t this ultimately run into the problem that you are part of what you are detecting? Sort of an cosmic preening in the mirror?

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    1. On being cautious, my stance is everyone who thinks QM has certain implications should try to push it as far as they can. I disagree with the QBists, RQMers, Bohmians, GRW theorists, and many other theory proponents, but think each camp should work as hard as they can to see how far they can push it. Even the Shut-up-and-calculate crowd, should push their approach to the limit. And of course I think the same for the Everettians.

      We just need to keep in mind that most of these camps, maybe all of them, are wrong.

      Everything being quantum means we are too. So there are implications for who and what we are, implications that many find disturbing. Is that preening? I don’t know, but I tend to think the approaches that say we are somehow essential for reality are in greater danger of that.

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      1. What about the conscious observer folks pushing it as far as they can?

        If everything is a quantum wave, then consciousness would be quantum, right? I guess you saw Vedral’s link to the Stuart Hameroff article.

        And reality would be analog?

        What unique prediction does his theory make that can be tested?

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        1. I should have been more clear above that I meant pushing it as far as they can scientifically. And absolutely the conscious observer folks should do that. If they’re right, there should eventually be advantages to seeing things that way.

          Consciousness is at least quantum in the same way that brewing coffee is quantum. The question is whether isolated quantum effects figure in the brain’s operations which, at least currently, seems like a dodgier proposition with its warm messy environment, but who knows what might be discovered in the future. Vedral did link to Hameroff’s article, but I think he was just being inclusive. As I understand it, adopting Orch-OR means adopting Penrose’s interpretation of QM, or something like it, with physical wave function collapses.

          Reality would be analog at the level of description we use for quantum waves and fields. It may or may not be continuous as we continue to go down. It could still eventually be discrete, or something we haven’t conceived of yet. In truth, we never know whether we’ve hit brute reality yet.

          On unique predictions, it’s more a combination of multiple predictions. Universal quantum waves means there’s no Heisenberg cut, so, in principle, no scale where quantum effects can no longer be observed. Of course, it gets progressively harder the higher up experimentalists go, but that’s more of a spectrum than a sharp cut.

          I know you’ll point out that RQM would say the same thing. There the difference is wave ontology (Everett say real, RQM says not real). I personally think quantum computing makes anti-realism here a difficult proposition. Philip Ball, in his book Beyond Weird, as someone who prefers epistemic views, has to admit they have no explanation for how QC works. But QC was developed by wave realists. They have their explanation for how it works in quantum states.

          That still leaves pilot-wave theory, but hidden variable theories break or complicate the reconciliation with special relativity and quantum field theory. For most physicists, that’s enough to discount it.

          I don’t know if that rules out every other approach, particularly since people come up with new interpretations all the time. But they do seem to narrow the field.

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          1. I doubt if the link to Hameroff’s article was quite that off-hand and quantum effects ought to be all over the brain as we would expect to find them in a coffee maker too. If they are there, they could be playing a role in consciousness if the theory is right. Warm and messy shouldn’t matter to the theory. I mean how do you argue the Pacific Ocean has an underlying waveform if a little fluid would mess it up in the brain.

            Does it even make sense to think of the Pacific Ocean as a superposition of some stuff that could be represented with a waveform?

            The fact is that quantum effects can only be detected with highly contrived, technical, and sensitive experimental setups. That’s certainly true with the 16 microgram sapphire that had to be shaken by a superconducting circuit to detect vibrations that were subatomic in scale.

            It makes more sense to me that quantum effects play a role at the microscale, but they wash out or average out at a larger scale. So, they are still there, even in the Pacific Ocean, but become useless for predicting El Nino, for example.

            Doesn’t bringing locality back violate Bell’s Theorem (not that I understand it)? Or, does he disprove it somewhere? I thought the theorem had been repeatedly confirmed.

            BTW, I’m not getting email notifications of your posts or comments but do seem to be getting likes. I haven’t changed anything. Is it just me or this is WP enhancement?

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          2. I think we can safely say the Pacific Ocean is very thoroughly decohered. But decoherence, in and of itself, doesn’t remove the quantum effects. It just fragments the interference so that it’s extremely difficult to detect.

            But I agree that quantum physics is useless for predicting El Nino or the stock market. I know Vedral says he wants to remove classical notions from physics, but as a practical matter they remain very useful in their domain of applicability. If universal wave mechanics is right, we just have to remember the classical concepts are emergent.

            Bell’s Theorem, as I understand it, assumes there’s only one outcome. But that wouldn’t be true under universal wave mechanics. The non-local dynamics comes from introducing a physical wave function collapse or hidden variables. https://en.wikipedia.org/wiki/Bell%27s_theorem#Many-worlds_interpretation_of_quantum_mechanics

            I’m still getting emails, but I have had incidents in the past where I didn’t. They’ve historically cleared up after a few hours. But I’ve also had events where my blog had issues, so I’ll keep an eye out.

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  5. The very word “information” is insufficient to explain this concept. Some new word might be appropriate but god knows what that word would be. Information traditionally describes – admittedly it is normally (inevitably) inscribed on or in matter but the essence of information, certainly in the way it is used here, becomes platonic. We are almost back to good old Penrose and his platonic mathematical realm. Which he deems to rule over the mental and physical realms. I’m not sure where causality fits into all this and I’m not sure Penrose is either. So everything is information and matter/energy effectively a perturbation of that. It all sounds very circular. I quite agree on pushing all these theories, but as it stands it fairly difficult to see what this fellows quantum wave actually is let alone how it’s perturbations create ourselves and everything around us. Great, we are “information” he says. How does information write a poem or sip a cup of coffee?

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    1. I think I’m missing the argument Vedral is making about information. I do see he is a professor of quantum information science.

      Personally I see information as causation, or maybe a snapshot of causation. So to me it’s completely physical. To the platonic argument, it seems like if we removed every physical instantiation of a piece of information, then the information would only still exist in the aftereffects of the erasure processes, recoverable in principle but not in practice.

      But modern platonism views abstract objects as non-causal with no temporospatial extent. It’s not clear what it means to say they exist. If they do, it seems like a different kind of existence from that of a person, river, mountain, planet, or galaxy. All of which inclines me to think there’s no fact of the matter. They are a convenient way of talking, but that talk could also just refer to mental constructs, with the platonic versions redundant.

      With quantum waves, one of the things we always have to remember is that these are the building blocks of reality. But the arrangements of those blocks, the higher level structures, where are emergent, matter, at least for us higher level structures. So saying writing a poem or sipping coffee are ultimately quantum mechanical events doesn’t mean it will ever be practical to model those events with quantum mechanics. There are just too many layers of abstraction between them, and our minds aren’t vast enough. But if Vedral and others are right, it does mean every possible version of that poem gets written and every possible version of that coffee sip happens.

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        1. We can think about it that way, but to Vedral’s point, that really underappreciates the full ontology. We can also think in terms of all of them happening in this universe, but with it extremely difficult, after decoherence, for us to interact with the other versions.

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  6. Wave/particle duality is an inference that is derived from the double-slit experiment, not a proof by any stretch of the imagination. Here are a couple of questions for AI, followed by AI’s response:

    Has it been demonstrated that the double-slit interference pattern is not caused by quantum particles like a projectile hitting other particles in the atmosphere?

    (Yes, it has been demonstrated that the double-slit interference pattern is not caused by quantum particles colliding with other particles in the atmosphere, as the experiments are conducted in a vacuum to rule out this possibility.)

    Is a vacuum capable of removing quantum particles from a space?

    (No, a vacuum cannot remove all quantum particles because quantum mechanics dictates that a true vacuum is impossible, as it’s always filled with virtual particles and fluctuations (zero-point energy) that constantly pop in and out of existence. Even in what we consider a “perfect” vacuum, these quantum fluctuations have real, measurable effects, such as the Casimir effect, a force that pushes two parallel plates together.)

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    1. I recommend caution with AI answers. Often they’re just conventional wisdom repeated, whether that convention is right or wrong. I try to always follow its citations (if provided) and ensure the AI isn’t making up the answer.

      Typically with the double slit experiment we see an interference pattern until path information about the particle (its causal effects) gets out into the environment. But if I recall correctly, the interference pattern degrades with longer distances between the particle gun, first screen, and second screen. The longer we make the distance, the greater chance it encounters something (air particles, electromagnetic radiation, etc) that leads to that information getting out before the back screen. It’s very hard to keep quantum systems isolated for any length of time, which is the main struggle quantum computing has to contend with.

      Not sure about virtual particles though. It seems like interactions with them would average out, without amplifying the effects. But I’ve never looked into that specifically.

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      1. “…the interference pattern degrades with longer distances between the particle gun, first screen, and second screen. The longer we make the distance, the greater chance it encounters something (air particles, electromagnetic radiation, etc) that leads to that information getting out before the back screen.”

        This is definitely a problem, but it does not negate the original argument that wave/particle duality is a “fallacious inference” for the reasons listed in my comment. Dismissing verifiable answers provided by AI is not an effective counter argument.

        Conventional wisdom: The double-slit experiment shows that the interference pattern arises from the wave-like nature of the particles themselves, and detecting which slit a particle goes through destroys the interference pattern. The pattern can even emerge with a single particle at a time, showing it interferes with itself rather than with other particles.

        Counter argument: The double-slit experiment shows that the interference pattern is caused by quantum particles colliding with other quantum particles creating a displacement wave in a test space where quantum particles always exist, and detecting which slit a particle goes through will destroy the quantum particles displacement wave that is responsible for the interference pattern. This would hold true even if there was a single particle used in the test.

        My counter argument is constituted by what we already know about wave dynamics such as a shock wave created by a high velocity projectile or a displacement wave created by a car passing through the atmosphere as it drives down the freeway. My argument is a viable alternate explanation for the double-slit interference pattern. Additionally, this explanation is in agreement with RQM which asserts; physics as physics is everywhere the same therefore, what happens in the quantum world is exactly the same as what happens in the classical world except for one variance; the quantum is a finer grain, not a wave function.

        Believe me I get it, old ideas die hard, slowly and sometimes never at all. But it’s like Rovelli always says…… Keep the math, but it’s time our vision of reality actually conforms to that landscape.

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        1. My question for your counter argument is, why does putting a detector at one of the slits make the interference pattern disappear? Presumably the virtual particles you’re referencing would be there regardless. Why do we ever not see an interference pattern?

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          1. “…why does putting a detector at one of the slits make the interference pattern disappear?”

            It’s called the measurement problem. Since the “displacement wave” is quantum, the measuring device destroys it.

            “Presumably the virtual particles you’re referencing would be there regardless. Why do we ever not see an interference pattern?”

            It is the “displacement wave” consisting of virtual particles that is creating the interference pattern, not the virtual particles themselves. Think wave mechanics Mike, it’s something physics understands very well.

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          2. “It’s called the measurement problem. Since the “displacement wave” is quantum, the measuring device destroys it.”

            I guess my issue here Lee is that under standard quantum mechanics we have an explanation for why a detector makes the interference effects go away: decoherence. The detection interaction alters the timing of the portion of the wave that passes through it, so that it no longer coherently interferes with the rest of the wave from the other slit.

            What would you see as the details of the detector destroying the displacement wave? And why wouldn’t we see an interference pattern from the displacement wave with just a single slit?

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          3. “The detection interaction alters the timing of the portion of the wave that passes through it, so that it no longer coherently interferes with the rest of the wave from the other slit.”

            Correct; and that is exactly what happens when the detector destroys the displacement wave under my regime. There is no difference because the mechanics is the same therefore, so is the outcome.

            “…why wouldn’t we see an interference pattern from the displacement wave with just a single slit?”

            For exactly the same reason that we do not see an interference pattern with a single slit under the current regime of wave/particle duality. Regardless of the “inference” derived from the double-slit experiment, mine or the standard model, the outcome is the same because wave mechanics is a well known, universal mechanism. The only distinction is that my model does not add unnecessary assumptions nor does it have any hidden variables; physics as physics is everywhere the same.

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          4. I’m still not clear why, if a particle produces a displacement wave prior to detection, it wouldn’t still produce it afterward. Or why only detecting it at one slit would make the whole thing disappear. I’m also not seeing how the displacement wave would produce the specific interference patterns we do see.

            But I’ll stop badgering. I appreciate the effort. Succeeding at replacing a scientific theory that’s been successful for a century is very hard.

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          5. You think you’ve got problems understanding. What I don’t understand is how a carbon molecule bucky ball once it is loaded into a bucky ball canon and fired, somehow becomes a wave. And then when this, I assume, carbon wave impacts the detector it turns back into a bucky ball.

            I’m sorry, but the rigorous hand waving particle/wave duality fallacy just doesn’t work for me; I don’t care what the math says.

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  7. Vedral starts from Heisenberg’s matrix mechanics (as does Rovelli), and refers to Heisenberg’s matrices as Q-numbers. Later, he goes on about q-numbers, which seem to mean the same thing as Q-numbers. Then he mentions that these q-numbers behave like waves. This means that field operators fulfil wave equations and spread out over space and time. He contends that the entire universe consists of interacting q-numbers, whose entangling interactions produce the appearance of definite outcomes.
    He elaborates on his approach in his paper: The Everything-Is-a-Quantum-Wave Interpretation of Quantum Physics https://doi.org/10.3390/quantum5020031
    Vedral posits that reality emerges from the interaction of q-waves with other q-waves. He refers to this as quantum entanglement. The q-waves are the physical manifestations or solutions of the algebraic structure defined by the q-numbers, which are the mathematical operators that describe the amplitude and dynamics of these q-waves.
    He argues that the measurement problem is resolved if everything is treated as a quantum wave. When observer states are modeled explicitly within the quantum framework as entangled q-waves with the rest of the system, the observer is simply another quantum system. Their apparent “classical” perception emerges dynamically from the interaction and entanglement with the system being measured. In addition, decoherence occurs as the overall state entangles and becomes orthogonal across different outcome branches. This means that the observer’s internal states become correlated with specific outcomes. However, the ontological claim that the world is made of q-waves entangling and evolving does not account for why a single outcome is observed in a single run.
    I don’t find that EQWI substantially moves beyond MWI or RQM in formal or empirical terms. It essentially takes the operator algebra seriously as the ontology and uses this approach to redefine measurement, observers and classical emergence. The explanatory function that Vedral attributes to ‘q-waves’, involving branching by entanglement and decoherence producing effectively orthogonal branches, as well as the concept of observers as quantum subsystems, does not seem to offer anything beyond what the Everett/decoherence approach or relational interpretations provide.

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Your thoughts?