The best way I can think about it, because I’m not smart enough and it hurts my brain, is that like the classic school physics problem where you always start with, “In a perfect vacuum with no gravity, xxxxxxxxxx.” More or less doesn’t exist in any macro sense as we know it, but enables us to reduce interesting problems in a consumable way. Quantum computing or quantum anything always seems to me like “Information can exist completely decoupled from your usual frame of reference, and by doing so do completely unintuitive things” and now we’re trying to figure out how to get a peek at the result, which up until recently smashed the whole construct by even trying.
A couple of things that kinda wrecked me when I read them from Richard Feynman, one of the fathers of quantum physics, is that fundamental particles, smaller than electrons but also sometimes kinda electrons, because they seem to be right on the cusp of where the weirdness starts, can just pop into existence. Theoretically they have energy, which means in the broad scheme they can be converted to mass, which means something can quite literally come into existence from nothing. And they do stuff! They generally do stuff in one direction for a tiny fraction of time and then disappear cancelling out what they did, but they did it, apparently.
The second was how mirrors have your reflection coming from every surface of the mirror rather than just the area where you would think the angle makes it happen, and I still don’t get that one.
The math is extremely complex to understand the fundamentals. It’s best to just wave your hand and say “scifi shit, parallel universes and such” and know that any mathematician would wince but yeah, kinda-sorta in the ballpark.
SO you know about wave/particle duality? Fire at a single slit and you get a even distribution, fire at two slits and you get an interference pattern, even if you fire one photon at a time and there’s “nothing else there” for it to “interfere” with?
Normal bits are like the particle model. There’s no way for two apparently independent things to interfere. To solve a “hard to reverse problem” - like cracking asymmetric encryption - you try all different possibilities as different paths through your program until you find one that looks like a solution.
qubits can be entangled and interfere, so you can get “wavelike” interference between the different possible paths a single photon could take through the system.
AIUI Quantum computation consists of arranging the interference so the “interference pattern” of all the possible paths through the program “shines” on where you want the result to be. You then fire a small (in relation to the number of classical computations needed) number of photons through the system and can with very high probability read off the result.
This is of course is an abstraction and I don’t even half-understand it the way I used to - but I think understanding it in terms of wave/particle duality is the best way of understanding what the underlying physical process is (even if you don’t understand that process or how it works) and how it allows you to “shortcut” things that would be very difficult with classical computing.
Heh, exactly. “you” are such a bizarre clump of everything that all this just constantly averages out and you have no possibility of perceiving it. It’s the substructure of the substructure of individual atoms, the stuff that we kinda know has to be there but we’re still trying to build a scope that can detect it. Granted, we can see the broader effects of these things, much like your eyes can’t see a bullet go by but you can see it hit some bottles of water and figure out what happened. At the atomic level you at least still have some frame of cause/effect that ramps up to our experience. At the subatomic level a lot of that goes out the window because those particles are traveling/existing on a spectrum so small that everything we know about inertia, speed, forces, etc. gets really fuzzy.
For my simple brain, I finally arrived at this to explain to myself the particle/wave duality, which is exactly what it says but isn’t very easy to grasp, because we exist in a reality that doesn’t support it.
If I stand against a wall, let’s presume that wall is waist-deep in water, and I have a hole on either side of me right at the water’s level. If you shoot a gun through either hole, you will never hit me, assuming you hit the hole and I’m skinny enough to have the angle right. But if you slap the water on the other side of the wall, that wave comes through the wall and spreads out in 180 degrees, so while I may not get all the wave, I’m still going to see waves lapping against me.
The double slit seems (and here’s where I get shaky) that you can measure a single photon of light doing both, depending on how you measure it.
If I’m not mistaken, and I probably am, at some level fuzzy is the thing. Even down to the Planck size. Once again we are stopped by the way we measure. At the big bang level, we should not try to go past a certain time. It gets to hot to measure at all.
At the lowest levels, once again we lose focus. Not measurable. Hell, even before that.
Well no, I’d say you’ve stopped early a bit. It’s not just the fuzz, that’s all about the various states things can be in. A well known particle like a photon that we can actually fire off one at a time exhibits completely nonintuitive yet completely predictable results. Quantum entanglement is a fuzz more, Einstein’s “spooky action at a distance” that he didn’t like. See my previous bullet analogy, a photon can act like a bullet or act like slapping the surface of water depending on how you look at it. That’s the mess.
Yes. I understand wavicle theory. But isn’t that just a basic understanding? This quantum computing is a big deal. That may well be explained at some time. By other computers? :)
Well, I absolutely don’t understand wavicle theory, is my point. It’s horrible and terribly counterintuitive to me, and quantum physics is a realm below that. I’ve read dozens of explanations of the double slit experiment and still barely get it at the “throwing rocks, and sometimes throwing rocks into a pond” level. Multiverse entanglement I can’t even begin to grok.
It seems like the main question is twofold: How can we make things that exhibit quantum behavior, which encompasses a whole lot of “I’m everything, thanks for asking” and then also extract meaning from it.
I have a friend who is much better than me at this and has explained it the same way to me. The idea that quantum entanglement can be used for instantaneous information transfer over a distance, or even for just faster than light speed, is a common misunderstanding and not a real thing.
I kind of understand the concept, but what I don’t understand because it’s never really been explained on a popular level is how to “ask the question” of a quantum system that quantum computers are doing. That is, I on a pop culture level “get” a bit of setting up a bunch of cubits that might be entangled and in quantum superposition, but when I “solve” I don’t really see how I’m getting a useful answer since that sort of implies some quantum weirdness about causation (ie, the system knew I was going to ask the question before I set it up).
Quantum mechanics is pretty horrifying but I’m still not entirely sold on multiverse ideas, mainly because it’s kind of like saying “the only solution to quantum multiplicity is infinity!” which seems just wrong and also kind of … incomplete.
I think it’ll be easier to say what they are once we (and by we, I mean the smart people) know better what real problems they can solve and can show it. I remember liking this scientist, even if the concept of different explanation levels never quite works out.
Yea, it’s interesting in that there was a lot of work put into spreading the understanding of atomic theory and atomic interactions, since these seem to be the domain of macroscopic features like chemistry, to the point where they try and teach everyone (in the US at least) at least something about electron orbitals and covalent and ionic bonds, ect, without teaching why it’s going on, just the what. There’s even been a lot of work spreading around the principles of Special Relativity, starting I think with Einstein himself (and which probably was a large part of how he became so widely known, and then kind of drug into the limelight the whole theoretical physics community with him over several decades).
But The Standard Model is off limits, and quantum mechanics is generally taught as a double slit experiment and the particle/wave duality, and left more or less at that. Even today there’s very little broad education about the Standard Model, and quantum mechanics has more or less entered the popular consciousness as “the universe is random” (at very small scales).
I can guess, but don’t know, that these concepts are so math heavy and math derived that only a vague notion is able to be communicated to ordinary people. Also that because it’s all so apparently beyond the experiences and need-to-know of most people, with little to no practical application, it’s generally left as a topic to science popularizers who have some financial incentive to find science topics to talk about. Lay people arguing over lay understanding of these topics is a bit like a villager arguing with another villager from a neighboring town about some line of scripture, when neither of them understand the Latin being read to them.
Yes, I was about to ask if I’d missed some news because the last I heard Many Worlds was as unprovable as the rest of the quantum interpretations but was being here assumed as fact.
