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Physicists provide support for retrocausal quantum theory

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Re: Physicists provide support for retrocausal quantum theory

#61

Post by ridewinter »

mikeash wrote: post #55
ridewinter wrote: post #51

Earlier quoted context omitted.

I think Deutsch would say there isn't actually a wave-particle duality. That's just an obfuscation that doesn't have any reality to it. Many-worlds has a much simpler explanation - there is simply a particle that interacts with particles in parallel universes that produce a wave-like interference effect.

He might say that, but so what? It's clear that he favors many-worlds, but that doesn't mean the rest of us have to. My point is that he's attempting to prove many-worlds by assuming that none of the other explanations are true, i.e. he's begging the question.

Well the other explanations say that the atom doesn't really exist, it's just an abstraction. And many-worlds says the atom does exist, and this is why you see these quantum effects. That's a meaningful difference.

Re: Physicists provide support for retrocausal quantum theory

#62

Post by [deleted] »

mikeash wrote: post #55
ridewinter wrote: post #51

Earlier quoted context omitted.

I think Deutsch would say there isn't actually a wave-particle duality. That's just an obfuscation that doesn't have any reality to it. Many-worlds has a much simpler explanation - there is simply a particle that interacts with particles in parallel universes that produce a wave-like interference effect.

He might say that, but so what? It's clear that he favors many-worlds, but that doesn't mean the rest of us have to. My point is that he's attempting to prove many-worlds by assuming that none of the other explanations are true, i.e. he's begging the question.

[deleted]

Re: Physicists provide support for retrocausal quantum theory

#63

Post by raverbashing »

akvadrako wrote: post #57
raverbashing wrote: post #54

Earlier quoted context omitted.

As simple as using God to explain how the universe came to be It's not about a simple explanation, it's about explaining using simple things. A wave is simpler than "infinite worlds"

The wavefunction is exactly the same as "infinite worlds". The essential aspect of the Everett / many-worlds view is that the wavefunction is the complete description of reality. The "worlds" are just approximate ways of slicing up the wavefunction which correspond to our sense of classical reality. They are clearly (and uncontroversially) identifiable if you run a simulation.

Ah that's a better explanation

Re: Physicists provide support for retrocausal quantum theory

#64

Post by metafunctor »

steven777400 wrote: post #25
ridewinter wrote: post #15

The many-worlds interpretation of quantum mechanics is the only one that's easy to understand. All others seem to bend over backwards to realistically explain quantum effects. It's so rare to find clear explanations, but they do exist. My favorite from David Deutsch, a main creator of the idea of quantum computing: To those who still cling to a single-universe world-view, I issue this challenge: explain how Shor’s al…

What about the interpretation that if reality is a computer simulation, certain operations (such as the factoring described) are a form of a security weakness in the simulation, allowing the simulation to "escape" and access/consume host computational resources?

That seems to me like a multiple universes explanation for people who also like science fiction.

I'd bet there's a simpler explanation.

Re: Physicists provide support for retrocausal quantum theory

#65

Post by mikeash »

ridewinter wrote: post #44
JadeNB wrote: post #31

Earlier quoted context omitted.

> My favorite from David Deutsch, a main creator of the idea of quantum computing: It's interesting, but this "I challenge you to answer a philosophical (not scientific) question in a way that I find acceptable" approach surely skirts uncomfortably close to dogmatically creationist arguments. (For the record, my answer, which certainly wouldn't satisfy Deutsch, is: it works because the math proves it works; there's n…

Math is used to explain the universe. It isn't an explanation in of itself. We never progressed anywhere by saying "something just works" and leaving it at that. Challenge yourself.

Seems like it's the opposite to me. We never progressed anywhere with "explanations." Progress comes when those explanations are condensed to testable mathematics.

I'm curious as to what you think consists of "an explanation" that's more useful than mathematics. Let's take a simple classical phenomenon to keep it easy, such as kinetic energy. The mathematical statement is E_k = 1/2 m v^2. What non-math explanation works better?

Re: Physicists provide support for retrocausal quantum theory

#66

Post by mikeash »

ridewinter wrote: post #61
mikeash wrote: post #55

Earlier quoted context omitted.

He might say that, but so what? It's clear that he favors many-worlds, but that doesn't mean the rest of us have to. My point is that he's attempting to prove many-worlds by assuming that none of the other explanations are true, i.e. he's begging the question.

Well the other explanations say that the atom doesn't really exist, it's just an abstraction. And many-worlds says the atom does exist, and this is why you see these quantum effects. That's a meaningful difference.

I'm pretty sure that's not what the other explanations say at all.

Re: Physicists provide support for retrocausal quantum theory

#67

Post by ajuc »

There's also the idea of timeless physics, as argued in https://en.wikipedia.org/wiki/Julian_Barbour#Timeless_physic...

or in slightly different form in http://lesswrong.com/lw/qp/timeless_physics

It's apparently possible to rewrite all physical equations without time coordinates and they still work.

I'm not competent enough to understand all of it and to check if it's not contradicting any experiments, but I'd love to hear if it does.

It seems particularly elegant (because if the state of the universe can't repeat, then why do we need time?).

Re: Physicists provide support for retrocausal quantum theory

#68

Post by roywiggins »

rf15 wrote: post #29
roywiggins wrote: post #8

Earlier quoted context omitted.

Entanglement would too, if it allowed superluminal communication in the classical sense. But, it doesn't- you can't use entanglement to send information, even if there is a spooky interaction at a distance. Retrocausality would probably work in the same way.

good comparison, sure sounds like entanglement in parts

I think the idea is to use retrocausality to replace entanglement. No spooky action at a distance- it's just that when you observe one of the pair, it retroactively "picks" the state it always was, which retroactively sets the state of its partner back when they were first entangled.

Re: Physicists provide support for retrocausal quantum theory

#69

Post by ethn »

ridewinter wrote: post #56
ethn wrote: post #48

Earlier quoted context omitted.

You continue to ignore the weak points of Deutsch's argument that I've pointed out. You can create a computing machine by assigning physical states to any physical behavior, quantum, classical, hamiltonian, etc. The proof is trivial and it is not a proof he came up with. It further follows, there is no computation happening during the creation of an interference pattern until we assign it our own abstract semantic st…

Many-worlds has a concrete, physical, simple explanation for quantum effects. The other interpretations are based in the abstract, and are incredibly difficult to understand. That's all I'm saying.

"There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is." -Niels Bohr

All of science is abstract, not even "force" describes something physical. There are many more concrete models like Bohmian that don't rely on unprovable conjecture.

Re: Physicists provide support for retrocausal quantum theory

#70

Post by BoiledCabbage »

ridewinter wrote: post #50
TheOtherHobbes wrote: post #46

Earlier quoted context omitted.

There are no photons. There are only photon-like events, with associated probabilities and scattering processes. It's a lot easier to assume that reality is the visible output of an heroically counter-intuitive but relatively tractable probabilistic calculation process, than it is to assume there are infinite universes with poorly defined boundary conditions between them and even more poorly defined properties, and t…

That's exactly what I'm saying! All other explanations say something confusing and obfuscating like "there are no photons". Many-worlds keeps it simple and says "there are photons, and the reason they behave like that is because they're interacting with parallel universes". You can't explain why they behave like that, so you say that the photon isn't really real, and have a complicated explanation of it.

Clearly this is all subjective, but Pilot Wave theory (De Broglie & Bohm) is the simplest least "crazy" of all the explanations.

Horribly simplified: Space isn't empty, there is an "ether". Matter moving through the ether interacts with it and produces waves just like a very light boat in a lake - these crests and troughs exactly line up with the magical waveform. All of the quantum behavior we see is explained by the waves in this "ether".

Ie the waveform is no longer this crazy math thing its a real thing. And just like "air" was considered empty until we discovered a vacuum, space itself is considered empty until we fully define the "ether". It matches up with all of the results of Copenhagen, but was dismissed because physicists like "locality" and it gives up locality.

But guess what? The surface of a lake is non-local. Your boat is affected by boats far away via waves, the effect just diminishes over distance.

And the double slit experiment is so straightforward now that it makes Copenhagen and many-worlds look kinda silly.

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