Jim B,,can you write a little more about how this experiment, or the idea behind this experiment, fits in the context of OP?
That question was already answered (it’s the way the universe works, and quantum theory was derived from an abundance of experimental evidence) but I’ll venture the suggestion that there may be even better answers in the offing.
The physicist David Deutsch asked what was in a sense a similar question many decades ago, asking in effect whether there was a practical application of quantum weirdnesses like superposition and entanglement that would be as much of an in-your-face practical demonstration of these phenomena as nuclear energy has been to the theory of relativity. He answered his own question this way: quantum computers. He proposed them long before anyone had any idea how they might be built.
Deutsch’s particular take on quantum computing is that it’s evidence of the literal reality of Everettian “Many Worlds” in which every wave function collapses into all possible states in a multitude of parallel worlds, a view that most physicists don’t share, or at least not with the same fervent certainty. Nevertheless, quantum computers are being built experimentally to exploit these quantum weirdnesses, and a practical quantum computer that runs Shor’s algorithm to factorize a number many orders of magnitude faster than would be possible with technology operating on classical principles might be a good answer to your challenge.
Thank you!
But not just any interaction. A particular character can remain in a superposed state until it interacts with a measurement. Even when the unknown character affects the interaction, “collapse” need not occur — both particles are now in entangled superposed states until a more positive measurement occurs.
I highly recommend a recently published book called “Beyond Weird” by Philip Ball. It does a very good job of explaining quantum weirdness, and the common misconceptions about it (and about what “detection” really involves).
While one can explain quantum computers in terms of the Many Worlds interpretation, one can also explain them in terms of any other of the many interpretations of quantum mechanics. All valid interpretations of quantum mechanics produce exactly the same measurable outcomes; if they didn’t, they wouldn’t be considered valid interpretations.
The favored interpretation among actual physicists, incidentally, is the “shut up and calculate” interpretation: Since there’s no way to determine which interpretation is “correct”, don’t worry about it, and just do the math.
So all valid interpretations of QM are both right and wrong at the same time, and there is no box we can open up to collapse them into a single position?
All of the interpretations are probably wrong in some detail (or perhaps “not even wrong”) and the actual underlying reality is probably much stranger than we can imagine. It certainly doesn’t follow any rules that are intuitive to us.
Stranger
You did the observation with your hand, not your eyes. It is still an observation. Not that QM doesn’t have something called “the measurement problem”, which I think the scientific consensus is that it is still unresolved.
Given any interpretation of quantum mechanics, and any definition of a measurement, the problem is simple to resolve. It’s only an issue if either your interpretation or your definition isn’t consistent.
Which, of course, says nothing significant about the rules, and plenty about our intuitions.
Sure, the world we live in and the rules it appears to operate by are nothing more than a rough and often misleading indication of the underlying mechanisms. And for all we know, there could be (and in my opinion, likely is) a more fundamental mechanic to the consistent but seemingly arbitrary rules of quantum mechanics. Whether we will ever be able to discern it in terms that “make sense” to our monkey brains is another question entirely.
Stranger
I find gauge theory to be pretty compelling. I imagine a particle as a sort of harmonic of frustrated placquettes that defines a location based on its focal point but is not actually a fully coherent entity (more like the pattern in the pond than the falling pebble that precipitated them). It is a notion born of my fundamental dilletantish ignorance, but it makes sense to me.
My mind is still whirling after all the complex posts given in reply. (But I also want to take the time to thank you all for at least trying to make your answers comprehensible:).)
I am not sure I understand your question. As someone said, my understanding of QM is clearly imperfect at best. But basically my question was, if conscious thought is necessary for individual realities to exist, what happens when you take away conscious thought? Because it seems to me, even that changes from situation to situation.
And also, not to take the discussion in a different direction. But has anyone ever seen that *Star Trek: the Next Generation * where Worf starts moving from reality to reality? No, I am not trying to start a new Café discussion. I just wonder if it is possible.
Is it?
Look at it this way… I know that a “solid” table is mostly empty space between the molecules. But this knowledge doesn’t give me the ability to push my hand through the table. I know that, a week before an election, millions of people are undecided (which means they are suceptible to persuasion). This knowledge doesn’t give me the ability to sway the election. I know that electrons exist only as probability clouds until they interact with some other particle. But this knowledge doesn’t give me the ability to survive electrocution. As much as New Age Bullshit would like to say otherwise, knowledge about the microscopic doesn’t translate into the ability to manipulate the macroscopic.
Reality only exists if there is someone to experience it?
Someone correct me if I am wrong, but QM does not have a definition of “conscious”. And the word need not appear in a textbook on QM. Although maybe a philosophical aside might use it.
Right but if this were true there would be a problem. The universe existed for a long time before any living beings with consciousness evolved. And when they evolved, they looked around and noticed that the universe didn’t blink into existence when the first conscious being in the universe evolved.
Unless you want to claim that since reality requires consciousness there must have been a consciousness to observe reality before the universe could exist, and label that consciousness “God”. Except why would you do that? That’s introducing one unnecessary unprovable entity (reality requires consciousness) and answering it with another unnecessary unprovable entity (there must have been a consciousness pre-existing reality), as well as an infinite regress of entities (the reality the pre-existing consciousness exists in plus the consciousness that pre-existed that reality, plus the reality that consciousness existed and so on).
Much easier to just do away with your unnecessary consciousness axiom.
I think that the idea “measurement implies consciousness, therefore consciousness is a factor in QM” is a mistake.
ETA: Oops, ninja’d
I just want to add, in response to the comments about quantum computers and Many Worlds, that the point of bringing up quantum computers was not that it’s proof of the MW interpretation – David Deutsch is in the minority in believing that it is – but in answer to the challenge of providing “A real-world application of quantum theory - that is, one in which quantum effects are used or harnessed or taken into account, to change something about me or my environment”.
Working large-scale quantum computers would answer that challenge in spades. The majority of their extraordinary computational power is directly attributable to the practical harnessing of the superposition of states and entanglement of their qubits, from which (in running Shor’s algorithm, just for one example) probabilistic solutions to otherwise intractable factoring problems can be extracted. This, in turn, would have profound implications for all the world’s encryption-based security. To quote the physicist and author Simon Singh,
As information becomes the worlds most valuable commodity, the economic, political and military fate of nations will depend on the strength of ciphers. Consequently, the development of a fully operational quantum computer would imperil our personal privacy, destroy electronic commerce and demolish the concept of national security. A quantum computer would jeopardize the stability of the world. Whichever country gets there first will have the ability to monitor the communications of its citizens, read the minds of its commercial rivals and eavesdrop on the plans of its enemies.
How’s that for using quantum effects to change something about you and your environment? :eek:
This isn’t about cats, but it is about boxes.
Say you buy a lottery ticket, and then you put the machine that picks the balls into a box, rather than the cat. At a predetermined time, the machine kicks on, and picks the balls.
Until you open the box, your lottery ticket is in a superimposed state of being both a winner and a loser. You can observe the ticket all you want, but without the information from the box, you cannot determine its state.
I have no idea if this thought experiment is useful, I just thought of it, and thought it may be interesting to share. It does eliminate parts of the cat in a box experiment that don’t make sense, and limits the uncertainty to information, rather than dead/alive.