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Experiments spell doom for physical-collapse explanation of quantum weirdness

quantamagazine.org

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Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#271

Post by isitmadeofglass »

lebuffon wrote: post #48

Don't tell anyone, but in the back of my mind I wonder if what we call quantum mechanics has something to do with the rendering engine in this simulation we find ourselves in. Is quantum collapse just us "catching" the engine deciding what to render when we observe something? :-)

Maybe. Considering that the simulation is taking place on a nearly infinite large white sand dessert with a turtle meticulously moving rocks according to a simple set of rules, there are bound to be hiccups in the physics engine part.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#272

Post by isitmadeofglass »

vpfaulkner wrote: post #36

From a layman’s point of view, it seems like we grasping at straws when it comes to these thorny quantum questions. Is fair to say, for example, that we are about as clueless as our ancestors were with the bubonic plague? To a non-expert it can be difficult to separate which theories lay on solid ground and which theories are highly speculative.

> Is fair to say, for example, that we are about as clueless as our ancestors were with the bubonic plague?

“We” in the collective sense are not clueless about quantum mechanics at all. We have an extremely exact model, and pretty much every attempt At proving that it’s insufficient fails. The only “problem” with quantum mechanics is the same as the “problem” we had in Newtonian mechanics when we found that a tennis ball and a bowling ball falling from head height hit the ground at the same time. This was a problem because intuition would have the heavier object fall faster than the lighter. It wasn’t an actual problem with Newtonian mechanics though mind you. Our intuition was counter to reality, the problem was the intuition not the model of reality.

Naturally there were other actual problems with Newtonian mechanics, but none of that had to do with making it more intuitive. And the same is true of quantum mechanics. It doesn’t sound intuitive to most people, but that’s not problem, it just means your intuition about how systems should behave at these scales is wrong.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#273

Post by masteranza »

masteranza wrote: post #235
masteranza wrote: post #214

This article is a perfect example how science is getting led into dark areas by people who didn't learn quantum mechanics right or people who pretend to understand it, but can only blindly follow the formalism without much understanding of what they actually do. Every such article continuous to mysticize the whole subject by quoting famous scientists who were either puzzled by it at the time or scientists like John v…

For anyone preferring to read latex, I invite you to my [blog]( https://wordpress.com/post/masteranza.wordpress.com/1135 ).

broken/wrong link, sorry: https://masteranza.wordpress.com/2022/10/22/there-is-no-meas...

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#274

Post by cb321 »

cb321 wrote: post #137
kgwgk wrote: post #91

Earlier quoted context omitted.

> intrication of observer into observed system as part of the measurement process That was already part of von Neumann’s model of measurement over 90 years ago.

Yeah. Perhaps most charmingly treated here: https://arxiv.org/abs/2011.12671 { EDIT: though surely many other places! There are also YouTube videos of this one, though, and Sidney Coleman was really a Feynman-class edutainer, perhaps as under-recognized as von Neumann is relative to say Everett on this topic :-) }. I should perhaps have used the word "entanglement" rather than "intrication". Oops.

Also of interest might be the treatment by Lev Landau in his Course on Theoretical Physics Volume 3: Quantum Mechanics - non-relativistic theory. Deriving the Born "postulate" is in Section7: "The wave function and measurements" in the most available 2nd edition (but it is admittedly a rather abbreviated derivation). I am not sure if that was in the original 1958 edition.

Quantum systems measuring other quantum systems is part & parcel of quantum computation. So that can lead to more clear thinking on (some of) these matters.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#275

Post by killerstorm »

lebuffon wrote: post #48

Don't tell anyone, but in the back of my mind I wonder if what we call quantum mechanics has something to do with the rendering engine in this simulation we find ourselves in. Is quantum collapse just us "catching" the engine deciding what to render when we observe something? :-)

A lot of people who work with computers get this idea. :) But it seems rather unlikely, as quantum-mechanical models are actually more expensive to compute. Quantization is not at all similar to pixelization or rounding effect, it's fundamentally different. Quantum computers being more powerful than classic computers hints that it's not a simplification, on contrary.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#276

Post by alexvoda »

whimsicalism wrote: post #138
herdcall wrote: post #54

Earlier quoted context omitted.

Check out "superdeterminism," first proposed by Bell (of Bell's inequality fame) himself and currently being vigorously pursued by Sabina Hossenfelder. There is no "collapse" per se according to this model and everything is really classical with hidden variables, and the entanglement comes because everything shared the same origin (the big bang). A very fascinating and in my opinion the best explanation, though it's…

> though it's extremely controversial and taboo because of its implications on free will Uhh, no. Essentially all existing physical theories are devastating for any non-compatabilist account of free will.

Free will is also incoherent in any religion or philosophy presupposing a bi-omni deity (which itself is an incoherent notion).

The point, that many ignore, however is that, free will does not matter. It is irrelevant. Regardless of whether one has free will or not, one still has to make choices and support the consequences of said choices. Lack of free will was never the get out of jail free card some fear it to be.

If you bring in to the discussion sociology and psychology, free will makes even less sense.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#278

Post by cillian64 »

lamontcg wrote: post #177
krohling wrote: post #171

Earlier quoted context omitted.

> it doesn't seem to offer much in terms of explanation of how the entangled state ends up being what it is: According to MWI, all possible results of an experiment are manifest and real. You're asking "which particular entangled state we end up in?". You end up in all of them. For a 2-state superposition system, there are 2 versions of "you" that exist after the experiment, both of which are equally real. Subsequent…

> You end up in all of them. Except that I've only ever experienced ending up in one of them, so exactly how did the "I" that is typing this right now wind up here, and not in some other branch? There's an unexplained bifurcation of consciousness implied by MWI which it cannot explain (although I think it suggests the appeal of MWI since it gives enough wiggle room that people think that their free will could control…

I’m currently reading Anathem so this is an interesting topic.

For simplicity, let’s say that all quantum interactions have two possible outcomes, 0 or 1.

The first point is that we can only talk about what interactions appear to have done in the past in our worldline/universe, which is randomly distribute themselves between 0 and 1. If we happened to be on a worldline where all interactions had always resulted in 0 for the whole history of the universe then that universe almost certainly wouldn’t support complex life. So perhaps there’s an observership bias here: if quantum interactions hadn’t decently distributed themselves between 0 and 1 then we wouldn’t be asking this question (just like the values of all the other fundamental constants).

As far as I can tell there’s nothing in current theories which would rule out all future interactions happening to result in a 0. Let’s hope our consciousness don’t end up on that worldline (unless you believe in quantum invulnerability).

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#280

Post by whimsicalism »

tsimionescu wrote: post #263
whimsicalism wrote: post #149

Earlier quoted context omitted.

> you then need to recover the relationship between the probability of observing a certain outcome and the amplitude of that outcome in the wave-function. I have never understood how that is a strong objection. We've experimentally determined that the state you are more likely to find yourself in is based on the squared amplitude. How is this different from CI but with probability of observing given state - which was…

> How is this different from CI but with probability of observing given state - which was also determined empirically? It's not different, that's the point. For both interpretations, the relationship between the probability of observing a certain outcome and the amplitude of that outcome in the wave function are an extra postulate, the exact same extra postulate in fact, the Born rule. > The worlds and their number a…

> The measurement apparatus as a separate thing from the quantum system was actually partially explained by decoherence

I disagree that the decoherence at all partially explains a different measurement apparatus separate from the system. After observation, we still have the the system is in a superposition of multiple states. How this system "collapses" to one state in the measurement apparatus is unexplained.

Decoherence explains why each state of the observer can't tell that the other states also exist.

> This is the most direct way of interpreting our experimental results.

Sure, except we have to invent an entirely new non-unitary transformation of "collapse" despite all observations and predictions of quantum mechanics showing that unitary evolution of the wavefunction continues even for large macro-scale objects.

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