As many of you have probably noticed by now, I've got a
Doggerel Index, covering a lot of the useless words and arguments woos use. I've got one in particular on the word, "
Quantum" that I'm considering updating, or making a sequel to. Maybe something like "Quantum Mechanics Proves [Woo]!" The reason for this is that
I've run into a woo who seems to be involved in a lot of misrepresentation about some of the well-known experiments, such as the double-slit thing and the Schroedinger's Cat jiggy.
I'm temporarily putting aside my knowledge of the experiments so that some of you more knowledgeable sorts can explain them (or link to some of the better explanations floating out there) and tell me what the results and terms actually mean, since I seriously doubt their weirdness is evidence for nebulous concepts like deities, free will, and psi.
I'm trying to write for people more lay than I am, so simplicity would be helpful where possible.
"Things should be as simple as possible, but no simpler." -Albert Einstein
I have to apologize for this. I've been thinking about this for a couple of days, and I hope you can forgive me for pointing out that your blog entry is largely wrong.
The word "quantum" by itself refers to, as I understand it, the smallest possible units of energy.
No. It just means that, in practice, energy or mass comes in lumps, and these lumps are of a certain size. It isn't continuous; it's quantized into lumps of a certain quantity. Hence the term quantum.
There is no evidence that energy itself is quantized.
A photon of light can have any energy. What this energy is is not quantized. You can have an arbitrarily low amount of energy in a photon, but you might need a really big antenna to make one. But a photon only has that amount of energy. QM says nothing about whether energy itself is quantized, however.
Because of this, quantum mechanics deals with very small stuff, down to fundamental particles. On that scale, our familiar Newtonian assumptions stop working, and probability takes a much bigger role.
No, twice. Quantum mechanics deals with the entire universe, arbitrarily big. There is no point at which classical (not Newtonian) assumptions take over. There is a point, fuzzily defined, at which they become good enough. People therefore decide to stop at that point, and say that it's classical, so that the can go home and go to sleep. It's just that at the range of the very small, it isn't possible to make this approximation. You have to, whether you like it or not, use the rules of quantum mechanics. But QM affects and in fact is everything at a macroscopic level as well.
The notion of probability only comes in at the interface between QM and classical thinking. QM, or better, QED is nicely deterministic. So is classical thinking. But when you translate between the two, you have to use probability.
Particles don't have a simple position and velocity assigned to them: They have a wave function, which "collapses" when "observed."
This is only one interpretation. An interpretation is a philosophical (not a scientific) idea of what "really" happens. It's used mostly for emotional reasons, to make a particular person happy, so that he and/or she can go to bed contented. This particular interpretation dates from John Von Neumann, a mathematician who did some stuff for Computer Science, though he stole a lot from Alan Turing. For some reason, it has hit the public interest, but few physicists, unless they're undergrads, think this way. Most common is the Copenhagen interpretation, which amounts to "shut up and calculate." The von Neumann interpretation is sometimes called the Copenhagan interpretation, which is wrong, but it has engaged the public interest anyway.
There seem to be plenty of interpretations of what wave function collapse is, but none of the good science ones involve consciousness in any way, like plenty of woos like to claim.
It's true that none of the good science involves consciousness (in fact, it can be demonstrated from experiment that consciousness is not required). However, the "collapse of the wavefunction" is itself part of interpretation, not of what the science tells us.
he woos probably got it from the use of the term, "observer" in many of those interpretations.
Of course, this is a problem. There are a lot of terms from QM that reflect a state of poor understanding. "Observation" is one of those terms, but then again, so are "wavefunction" and "particle-wave duality."
It's best to get an overall understanding to skip quantum mechanics entirely and go directly to the more modern relativistic quantum field theories, such as quantum electrodynamics (QED) with its concept of summation over histories. Unlike QM, this stuff makes sense, though it says the same thing, only better.
I'd like to be able to describe the exact textures and composition of the carp.
