Slashdot Mirror
Researchers Identify 'Tipping Point' Between Quantum and Classical Worlds
wjcofkc sends this report from R&D Magazine:
If we are ever to fully harness the power of light for use in optical devices, it is necessary to understand photons — the fundamental unit of light. Achieving such understanding, however, is easier said than done. That's because the physical behavior of photons — similar to electrons and other sub-atomic particles — is characterized not by classical physics, but by quantum mechanics.
Now, in a study published in Physical Review Letters (abstract), scientists from Bar-Ilan University have observed the point at which classical and quantum behavior converge. Using a fiber-based nonlinear process, the researchers were able to observe how, and under what conditions, 'classical' physical behavior emerges from the quantum world.
Now, in a study published in Physical Review Letters (abstract), scientists from Bar-Ilan University have observed the point at which classical and quantum behavior converge. Using a fiber-based nonlinear process, the researchers were able to observe how, and under what conditions, 'classical' physical behavior emerges from the quantum world.
This is just supposition, but it's the way I choose to understand it. Note: This is probably not science.
Imagine you're a time traveller but in the classic Hollywood sense where timelines can be broken without the end of the universe, etc. Marty McFly doesn't have to worry about standing next to his former self and breathing in the oxygen he would have originally breathed in, etc.
You can go back in time, steal some cash from yourself, bring it back to a different timeline, use it to make yourself rich. It's all fine. So long as, at some point, you can back and put that money back for you to steal in the first place. This is similar to how particles they borrow energy. So long as nobody notices (in this case, so long as the energy is returned before the "uncertainty" in the uncertainty principle can be resolved), you're golden.
Additionally, you are both "in" the room stealing the cash and "out" of the room simultaneously at the same time because you've been jumping back and forth in time (and maybe even in the room watching yourself stealing the cash in order to put it back once you're gone). In one timeline, in 1956, you were there. In another, at the EXACT SAME TIME, you weren't. So asking "where were you at this exact time in 1956?" doesn't give a simple answer. I was here. I was there. I was not here at all. And I was all of them at the same "time".
Time is just a dimension, so it's one hypothesis that particles may well be doing exactly this - hopping back and forth through other dimensions of space (and thus disappearing from ours and reappearing somewhere else), jumping back and forth in time.
So long as they repay their debts, it all works out and doesn't violate (certain readings of) energy conservation laws. And particles aren't intelligent creatures that decide to do this, they may just be "things" bouncing through dimensions quite ordinary to themselves but "time", "parallel universes", "alternative histories" etc. to us. Following even the simplest of physical rules in those circumstances could look like the weirdest actions ever from certain points of view.
Imagine you're on a 2D universe, you are a piece of paper and cannot perceive things not on your surface. A "ghost-like" car tyre passing through your universe will come from nowhere, grow, change shape, look odd, etc. and then disappear and never have looked like a car tyre. Same kind of thing. If you can't perceive the extra dimensions, this horrible weird-shaped thing just pops into existence, wobbles about a bit as a strange-shaped silhouette, maybe forms a hole in the middle if it fell the right way, then disappears. Or maybe it fell perfectly straight and you ONLY ever perceived a rectangle-like shape coming and going. Same object, same thing happening, tiny change in parameters, totally different outcomes that are very unpredictable for you.
The problem with quantum stuff is that we just don't perceive other dimensions at all, but the maths does.
(x) describes how far along a ruler you are.
(x,y) describes where a pixel is on a 2D screen
(x,y,z) describes where you are in a 3D world.
(x,y,z,t) describes an EXACT point in space and the time you were there (e.g. your birth).
(x,y,z,t,q)? We have no way for you to perceive that. But mathematically it's just another co-ordinate.
Don't expect a layman to understand it. The geniuses don't understand it. They can describe it. They can measure it. They can produce the formulae. But, just taking the knock-on effects and working backwards, they'd have nothing. It's only because the maths comes up with weird outcomes and that we then FIND those weird outcomes in the universe that anything actually looks right. Trying to play it backwards from the weird outcomes to those formulae that you can't understand is never going to help you.
It's like being a blind man and wondering how people can know there's a silent car coming when you can only detect a car's sound. If you can't perceive entire dimensions that - we're pretty sure - are required to exist for quantum mathematics to work, then you're only ever going to see a third of the story (our current best guess is 11 dimensions - we think - as a minimum? So eleven letters in the above example!).
Consider this scenario. You are a two dimensional creature. You are only able to experience your reality as a flat plane. Up and down have no meaning to you; these are concepts quite beyond your comprehension. You cannot imagine a 3 dimensional object any more than we, in our 3 dimensional world, can imagine what a 4 dimensional object would look like.
Now, in your 2 dimensional world, creature, I, as a 3 dimensional God-like character, am going to take a circle, anything round, and shove it down through your plane of existence. What would you experience? You would experience at the very first, a single point suddenly appearing as if out of nowhere. This single point splits into two points that diverge from each other at a steady rate. Yet if I stopped pushing the ring through your plane for a moment and let you examine one of those two points that you can see, you would find that if you shoved on one point, the other point moved exactly the same. From my God-like perspective, all you did was shove the ring a bit. You, on your flat plane, see spooky action at a distance, because you're shoving one point and the other one is moving, too.
Given enough time and experimentation with these points that keep appearing in your plane of experience as I keep shoving rings and perhaps even more complex objects through your plane, you might even be able to come up with some really complicated mathematics and physics that describe all this bizarre motion and behavior in your 2 dimensional world. To you, it all appears incredibly complex and horribly incomprehensible, even utter nonsense, but you can manage to describe it in such a way that is at least consistent with the weird behavior you keep seeing. To me, in my 3rd dimension, I'm just chuckling over all that hard work you're going to, because to me it's just a simple ring I'm shoving through your plane and watching you go batshit crazy trying to figure out what's going on.
The point is simply that quantum physics appears bizarre to us because we are limited to experiencing 3 spatial dimensions and are forced to constantly move in a single direction on an axis of time. All the weirdness of quantum physics really just means that there are almost certainly many more spatial dimensions and more complete freedom of motion through time than what we are limited to experiencing. What you're seeing a lot of times is just the weirdness of seeing something that almost certainly "completely" exists in several more higher dimensions intersecting limited reality you are able to witness.