2022-10-05 15:29:20 <KipIngram   > :-)
2022-10-05 15:29:36 <KipIngram   > Or were both slaughtered and not slaughtered.
2022-10-05 15:30:00 <KipIngram   > The way the popular press "says quantum things" bugs the hell out of me.
2022-10-05 15:30:25 <KipIngram   > They'll say things like "the electron is in multiple places at the same time," or "has both spin up and spin down at the same time."
2022-10-05 15:30:49 <KipIngram   > That's entirely bogus - before you can even legitimately TALK ABOUT the position of the electron, you need to MEASURE that position.
2022-10-05 15:30:57 <KipIngram   > And when you do that you will find it in one and only one place.
2022-10-05 15:31:26 <KipIngram   > For the quantum state to be "in a superposition of multiple position eigenvectors" is NOT the same thing as the electron BEING in those positions simultaneously.
2022-10-05 15:32:27 <KipIngram   > Being in a superposition of states means that "upon measurement, you may find it in any of those outcomes."  You don't know which one, and when calculating certain things you need to consider all of those possibilities.
2022-10-05 15:32:43 <KipIngram   > But those aren't "real existent outcomes" yet.  You will only get one of them.
2022-10-05 15:33:11 <KipIngram   > But they can't help themselves - they just have to go for the "woo factor."  Make it all sound mysterious and sensational.
2022-10-05 15:34:17 <KipIngram   > It's a rampant problem.
2022-10-05 15:34:21 <thrig       > if they don't readership tanks and then they get laid off
2022-10-05 15:34:21 <KipIngram   > rampant
2022-10-05 15:34:30 <KipIngram   > No doubt.
2022-10-05 15:34:34 <KipIngram   > Vicious cycle.
2022-10-05 15:34:59 <KipIngram   > It's perfectly possible, though, for a quantum state to NOT HAVE a "value" for a particular thing you might measure.
2022-10-05 15:35:14 <KipIngram   > If you measure it, it will push it into a state that does, and you'll get the corresponding result.
2022-10-05 15:35:26 <KipIngram   > But not all states of an electron HAVE a "position."
2022-10-05 15:36:28 <KipIngram   > In particular if it's in a well-defined momentum state then the state just doesn't correspond to any position.  You have no idea where you will find it if you look.
2022-10-05 15:37:17 <KipIngram   > Values of observables don't exist until you measure them.
2022-10-05 15:37:41 <KipIngram   > So instead of saying it's "everywhere at once," they should say it's "nowhere."
2022-10-05 15:38:02 <KipIngram   > That's still not perfectly crisp language, but it's better than the other.
2022-10-05 18:41:40 <lispmacs[work]> KipIngram: I'm not a physicist, but was just wondering: is an electron a "thing" that is in a "position" or is it some kind of wave or field?
2022-10-05 19:02:58 <thrig       > generally you install electron and then the CPU fans run, so that's more a wave I guess
2022-10-05 21:50:52 <KipIngram   > It's a unit of energy in a quantum field.
2022-10-05 21:51:04 <KipIngram   > Electrons and positrons share the same quantum field.
2022-10-05 21:51:39 <KipIngram   > Energy can only enter or leave that field in discrete amounts; each chunk is what we call an electron or a positron.
2022-10-05 21:52:17 <KipIngram   > Each bit of energy has a frequency associated with it; for a given frequency the "chunk size" is that frequency multiplied by Planck's constant.
2022-10-05 21:53:18 <KipIngram   > There's a separate field for each type of fundamental particle.  If a particle has a distinct anti-particle then they go together in that field.
2022-10-05 21:53:34 <KipIngram   > But some particles (like photons) are "their own" antiparticle.
2022-10-05 21:53:52 <KipIngram   > All that really goes on in the world is that chunks of energy shift from field to field.
2022-10-05 21:54:45 <KipIngram   > Given the overall energy distribution in a pair of fields, you can compute the probability of an energy chunk (a "quantum") moving between those two fields.
2022-10-05 21:55:39 <KipIngram   > When that happens a particle or particle/anti-particle pair in the field losing the energy "annihilates,", and a particle or particle pair is "created" in the field receiving the energy.
2022-10-05 21:56:21 <KipIngram   > So a photon can disappear and an electron as well as a positron can appear, or vice versa.
2022-10-05 21:57:33 <KipIngram   > Particle like the photon that are their own anti-particles have spin zero and charge zero.  Particles with non-zero either one of those or both will have an antiparticle that has opposite spin and opposite charge, so when that pair appears or disappears spin and charge are conserved.
2022-10-05 21:58:34 <KipIngram   > Really all quantum field theory is is a complicated set of rules for how the energy moves around.
2022-10-05 21:59:44 <KipIngram   > Almost everything you see happening around you in the world has to do with just the electron/positron and photon fields.  Electronics, chemisty, optics, acoustics, strength of materials, chemistry, etc.  Everything except stuff happening inside atomic nuclei.
2022-10-05 21:59:59 <KipIngram   > And gravity - gravity is the odd man out in quantum field theory.
2022-10-05 22:00:15 <KipIngram   > That's the big wart - no one has figured out how to roll gravity into the setup.
2022-10-05 22:00:30 <KipIngram   > Every time they try it blows up on them - gives infinities and stuff.
2022-10-05 22:00:40 <KipIngram   > They've been working on that for like 90 years.
2022-10-05 22:04:27 <thrig       > Einstein at least got his part alll squared away
2022-10-05 23:10:54 <KipIngram   > There was a pretty major disagreement over the  years between Einstein and Bohr.  Einstein wanted a theory that didnt have all the probability stuff in it.
2022-10-05 23:12:11 <KipIngram   > But in the 1960's a guy named Bell came up with a way to put it to the test.  In the 70's digital tech got far enough along to do the tests, and it turns out a theory like Einstein wanted isn't possible.