Okay, here is how I think it might work—I am not a quantum computer programmer, so take my ideas with lots of salt.
Imagine a completely classical world. Imagine a bit (e.g. a coin faceup or facedown) inside of a container (e.g. a cup). Imagine a fundamental physical operation something like shaking the cup. If you don’t know whether the bit is faceup or facedown, then you might imagine that inside the cup are two superimposed worlds. That is, you can imagine that the world is one possibility thin where you are, and then bubbles out to be two possibilities thin inside the cup.
When you shake the cup and then open the cup, one way to describe what happens is that the superimposed worlds “collapse”, nondeterministically, into one of the possibilities. This is something like popping the bubble. Another way to describe what happens is that the bubble expands through you, splitting you, and one of the copies sees one of the possibilities, and the other copy sees the other possibility.
We can model entanglement in this classical world—imagine taking the cup-coin combination, and passing it through a duplicator. You still don’ t know whether the coin is heads or tails, but “collapsing” one will also “magically” collapse the other.
This is all well and good, you say—but it isn’t quantum computation.
My understanding here is fuzzier. As I understand it, there’s an additional “imaginary” dimension in the quantum computation than there is in the classical possibility-worlds that we’ve been talking about. Sometimes, the bubble or stack of possible worlds, when viewed from the outside, can have constructive or destructive interference, as if the different worlds were transparencies that one can stack and look through.
To the QC novices—does that make sense? To the QC experts—is that even roughly true?
As to the author of the post to whom your responding what is your level of knowledge of quantum computing and quantum mechanics? By this I mean is your reading on the topic confined to Scientific American and what Eliezer has written or have you read for example Bohm on Quantum Theory?
Vague grasp of what the maths is supposed to do, without ever having actually worked through most of it. More than just SA and Eleizer, but mostly pretty much around that level.
The trouble with the explore-and-prune way of describing these things is it automatically makes people fall into speculation on what’s doing the choosing, how maybe ‘consciousness’ is picking the ‘best’ of the results and shaping the universe.
Understand enough to know it ain’t that, and that the maths tells us the probabilities of the outcomes, there’s no 3rd party ‘picking’ the one most advantageous to ’em.
But it’s hard to get people to understand that without a good intuitive picture of what’s really going on, just seemed to me that the problem was probably the ‘collapse-like’ system which everyone seems to fall back on when trying to produce this intuitive picture.
Personally I should probably work through the maths at some point. It’s on the list. The list is long though and I have a goddamned job so I never seem to get proper time for stuff.
Not sure that having done that would help to convince people who certainly won’t be working through the numbers that there’s no special consciousness effect going on though.
Okay, here is how I think it might work—I am not a quantum computer programmer, so take my ideas with lots of salt.
Imagine a completely classical world. Imagine a bit (e.g. a coin faceup or facedown) inside of a container (e.g. a cup). Imagine a fundamental physical operation something like shaking the cup. If you don’t know whether the bit is faceup or facedown, then you might imagine that inside the cup are two superimposed worlds. That is, you can imagine that the world is one possibility thin where you are, and then bubbles out to be two possibilities thin inside the cup.
When you shake the cup and then open the cup, one way to describe what happens is that the superimposed worlds “collapse”, nondeterministically, into one of the possibilities. This is something like popping the bubble. Another way to describe what happens is that the bubble expands through you, splitting you, and one of the copies sees one of the possibilities, and the other copy sees the other possibility.
We can model entanglement in this classical world—imagine taking the cup-coin combination, and passing it through a duplicator. You still don’ t know whether the coin is heads or tails, but “collapsing” one will also “magically” collapse the other.
This is all well and good, you say—but it isn’t quantum computation.
My understanding here is fuzzier. As I understand it, there’s an additional “imaginary” dimension in the quantum computation than there is in the classical possibility-worlds that we’ve been talking about. Sometimes, the bubble or stack of possible worlds, when viewed from the outside, can have constructive or destructive interference, as if the different worlds were transparencies that one can stack and look through.
To the QC novices—does that make sense? To the QC experts—is that even roughly true?
I recommend some reading: http://en.wikipedia.org/wiki/Quantum_computer Start with this and then if you want more detail look at: http://arxiv.org/pdf/quant-ph/9812037v1 The math isn’t to difficult if you are familiar with math involved in QM, things like vectors, and matrices etc. http://www.fxpal.com/publications/FXPAL-PR-07-396.pdf This paper I skimmed it seems worth a read.
As to the author of the post to whom your responding what is your level of knowledge of quantum computing and quantum mechanics? By this I mean is your reading on the topic confined to Scientific American and what Eliezer has written or have you read for example Bohm on Quantum Theory?
Vague grasp of what the maths is supposed to do, without ever having actually worked through most of it. More than just SA and Eleizer, but mostly pretty much around that level.
The trouble with the explore-and-prune way of describing these things is it automatically makes people fall into speculation on what’s doing the choosing, how maybe ‘consciousness’ is picking the ‘best’ of the results and shaping the universe.
Understand enough to know it ain’t that, and that the maths tells us the probabilities of the outcomes, there’s no 3rd party ‘picking’ the one most advantageous to ’em.
But it’s hard to get people to understand that without a good intuitive picture of what’s really going on, just seemed to me that the problem was probably the ‘collapse-like’ system which everyone seems to fall back on when trying to produce this intuitive picture.
Personally I should probably work through the maths at some point. It’s on the list. The list is long though and I have a goddamned job so I never seem to get proper time for stuff.
Not sure that having done that would help to convince people who certainly won’t be working through the numbers that there’s no special consciousness effect going on though.
That’s quite an intuitive QC explanation as far as I can tell but I don’t think it was what pre was after.