Yes, a boring title. But the question is rather simple. According to the Uncertainty principle, the state of a particle cannot be known accurately entirely. We describe this as a Wave Function. That is to say, since we do not know with certainty a given state, we give it a wave function. Let's use Schrodinger's poor cat...: Cat State [alive/dead] Forgive me, I hate TEX editing... The wave function expresses a probability, that is to say, the cat is considered as both alive and dead- at the same time. This is because we do not know that state of the cat with certainty. Now, let's say we measure the state of the cat. In this case, as simple as opening the box and observing it (Easy to do in the macroworld...) The wave function will collapse to the observed state of the cat: [alive] Hey, I didn't want a dead cat. Because of this, I have adhered to the Copenhagen Interpretation. This being the case, isn't the collapse of the wave function just the observation of the actual state, not the determined state? Observing the state causes the wave function to collapse, but many express that they believe that observation determines the state that it collapses to, rather than observation reveals the state it collapsed to. Thoughts?
My first thought is for poor old Schrödinger. He proposed the cat-in-the-box scenario to demonstrate the absurdity of the Copenhagen Interpretation, but it's been hijacked and is now used to promote the quantum weirdness that attracts attention and sells magazines. See wikipedia and note this bit: "Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; quite the reverse, the paradox is a classic reductio ad absurdum.[2] The thought experiment illustrates the counterintuitiveness of quantum mechanics and the mathematics necessary to describe quantum states. Intended as a critique of just the Copenhagen interpretation (the prevailing orthodoxy in 1935), the Schrödinger cat thought experiment remains a typical touchstone for all interpretations of quantum mechanics". My next thought is that the Copenhagen Interpretation has been under pressure of late. See the physicsworld article Catching sight of the elusive wavefunction along with The secret lives of photons revealed. It might be worth your while reading A Physics-based Disproof of Bell's Theorem by Ed Klingman. He gives me a mention - I'm John Duffield. Or if that's bit heavy check out Jeff Lundeen's home page. To cut to the chase it's looking like wavefunction is real as is the wave nature of matter, and an interaction is something like a Fourier transform rather than a probability collapse caused by the God-like act of observation.
My laymen's understanding - we have mathematical models to describe the probable outcomes of a given situation. We do not determine the outcome when we open the box, we only observe what the outcome was. This becomes more complicated when observing things at the subatomic level. It's not like we can just open a box and watch a photon or an electron.
The quantum darwinism of Wojciech Zurek is an alternative that mingles aspects of CI collapse with the decoherence of the Everett Interpretation (without being concerned about "Many Worlds"). A process compared to natural selection leads to the superposed quantum states being pruned to a stable pointer state of classical reality, or set of such that undergo further evolution at the macroscopic level. Constant interactions with the background environment, like its ocean of photons, play the chief role in discarding any outright necessity for human measurements / conscious observers. But the circumstances of the specific interactions may contribute to which classical situation "wins the contest" or manifests.
Well I don't know or especially care what's in those magazines (I don't read them), but as a statement about what the physics community thinks, it's completely off. As the stereotype goes, ask two physicists what they think of Schrödinger's cat and you could get three different answers. In fact the Wikipedia article you quoted even alludes to that: i.e. different interpretations have different things to say about Schrödinger's cat. It's always been under pressure. There have been a variety of alternative interpretations to quantum physics in the last 60-70 years. Just for the record, the theory behind weak measurements dates from the 1980s and is an application of well established theory regarding measurement in quantum physics that arguably dates back to von Neumann. So the behaviour in question isn't new. Only the experimental verification of it is. Incidentally, a die hard supporter of the Copenhagen interpretation would not consider that weak measurements or the von Neumann measurement scheme contradicted it. In my opinion you could very reasonably disagree with the Copenhagen interpretation, but this experiment doesn't add to the case against it. Yet there's no physics in that disproof. He starts by citing Joy Christian's work, which is bogus as I explained in a [POST=2564656]previous post[/POST]: The problem with Bell's theorem, unfortunately, is that maybe the majority of physicists are even less familiar with it than Joy Christian is, so his bogus "disproof" generated quite a few equally bogus rebuttals. But you can find one that really hit the nail on the head and makes more or less the same point that I did here. Someone called "Jim Black" also did an excellent job of explaining Christian's misunderstanding in a forum discussion. What's a bit bizarre is that some of the language Christian uses in his papers indicates he's familiar with some of Bell's later papers. It also turns out he had Abner Shimony (the 'S' in 'CHSH') as a PhD advisor. So he should be well placed to understand why his own work is wrong. As for Ed Klingman's own account of things, just like Joy Christian the first sign he's heading down the wrong path is his obsession with the Stern-Gerlach experiment. He says: There's two related things wrong with this statement. The first is that Bell's theorem is (partially) inspired by the EPR paradox, but is not based on it. Bell's theorem also has nothing specifically to do with the Stern-Gerlach experiment: that's only one commonly used expository example. What Bell did was broadly define a "black box" concept of locality. Bell was very careful to define his concept of locality in a way that does not depend on any technical details of how Stern-Gerlach experiments are implemented. He doesn't even assume it is spins that are being manipulated. So right from the beginning, any technical analysis of spins or Stern-Gerlach experiments is never going to reveal a flaw in Bell's theorem. The CHSH inequality in particular applies to any experiment where results can be grouped into binary outcomes, which means it applies to just about anything. I rather resent you painting things this way, given I've already told you that the issue of observation is generally regarded as an open problem in quantum theory. Have you ever heard of the Many Worlds interpretation of quantum physics? The one that claims a superposition of all the outcomes of a measurement and observers who see them exist in parallel? Well a lot of perfectly sane and intelligent physicists take this interpretation seriously because it promises a relatively natural way of understanding measurement, without wavefunction collapse, in the context of quantum physics. That's actually what the MWI is specifically intended to accomplish. That's how seriously we take the measurement problem in quantum physics.
Thanks for the links, I will check them out. In some cases, that's my take - anything the an interfere with the outcome in any event. Please Register or Log in to view the hidden image! Reasonably, I'm curious about the natural state as CC suggests. This stems from people concluding that the Universe behaves as such only because we observe it. Which smacks of arrogance, to me.
Someone recently posted an article on here somewhere... and I'd have to find it... that demonstrates that MWI has as much evidence to support it as Evolution. I admit I would find that a stretch... But I'll look for it and if I find it, repost it here. The rest of your post went into details that I'm still absorbing.
It's not just arrogance, it's also elusive and usually inconsistent when the details are fleshed out. What about a robot? A camera? A semi-conscious observer? I'm fairly sure this point-of-view regarding QM phenomena has been largely abandoned.
This my be reasonably obvious from the other thread farsight is currently posting in, but while information provided by him may be completely true it may also be complete rubbish as well. If I were you I would only read one of his links if my bullshit detector was calibrated and fully operational.
I have noticed that you two have very different opinionsPlease Register or Log in to view the hidden image! I lack a bull** detector, sadly, but independent verification can be quite helpful and asking others that may know on the topic. Truth told I um... <cough> haven't actually opened any of those links yet... But when I do, I'll give my commentary on them and hopefully get some insight on whatever's said.
Yes, macroworld tools for observation are largely, too big. Heh...Please Register or Log in to view the hidden image! The arrogance I refer to is this: It sounds religious to me- We, who appeared as observers only within the last 6,000 years, no... wait, 125,000 years (my bad!) Suddenly Influence The UNIVERSE (Insert Booming announcer voice here) Just by peeking at it. My deck is stacked toward a natural field that we know little about as of yet and lack the tools necessary to observe it properly. Occams razor: that strikes me as much more plausible than saying the universe revolves around our perceptions of it. Especially considering that you get the same results in macroworld experiments, again and again. I'm far more likely to accept the answer that our ability to observe the infinitesimal is lacking than to accept that the Universe responds to our observations- without a great deal of extraordinary evidence to support it.
Hey, I know! Let's try not observing it for a while and see if the observations change. Please Register or Log in to view the hidden image!
Anything which causes the wave function to assume a definite value. The term 'observation' was a translation from German and very poorly chosen. It has nothing to do with some sentient consciousness.
An interesting experiment, where light can be both wave and particle at the same time? :shrug: http://arstechnica.com/science/2012...rticle-duality-in-the-double-slit-experiment/
One of the things I always wonder when I think about the measurement problem is time. How does "time" work at the quantum level and how does that relate to us? <cough> ouch I hurt myself... http://arxiv.org/abs/1105.3604
