A background of physics and it's theoretical potentials for fiction

No, entanglement is not relevant to quantum computers, at least not as we understand them right now. It would be nice to use entanglement to work through some various types of problems, but we can't do it right now. Right now, we're still trying to figure out how to properly handle the superposition. I've also considered keeping entangled particles in loops and making one time message passers, but such a thing just doesn't work mathematically, you can't keep it in an entangled state and know that you are bringing it with you.

 

Not sure if this is off-topic or not, but... I know I have been guilty of misunderstanding particle/wave duality and the concept of "Schroedinger's Cat" in ways that could make for a cool but inaccurate story concept.

Turns out, when people say that particles and waves act differently when they're being observed, they don't mean in some kind of weird metaphysical way; "observation" of quantum interactions actually refers to "experimentation" in a more meaningful way. That is, when they fire the wave/particle through the slit, it doesn't react differently if the scientist's back is turned; it's just that we don't quite know why one particle acts as a wave and one acts like a particle. So, the only way of finding out is by shoving it through a hole and watching the results. Basically, the methodology messes with the result because of the extent to which we just don't understand sub-atomic physics.

I might be WAY off here, btw, I just "learned" this a bit ago. The point is, the "Schroedinger's Cat" thing and the experiments and interpretations it's commenting on aren't as quasi-philosophical as I and, I believe, many others thought. Kind of disappointing, actually.

Also, dark energy is fascinating. Apparently it's involved with the process by which empty space reproduces itself infinitely? Huh.

 

I'm sorry, but you were closer to understanding the particle-wave duality the first time. Experimentation or even observation has nothing to do with "observation" in particle physics. I really hate that "observer" is a quantum mechanical term because it's so ridiculously misleading.

An "observer" is anything that interacts with a particle (a photon is the most likely observer, but it can be any particle.) The reason they use this term is because it's the measurement of what they call an "observable." An "observable" is any property of a particle that can be measured (velocity, location, [quantum] spin, charge...) Particles do not move as waves, but rather their position is determined by a probability and that probability distribution is described via a wave function. The particle does not stretch out, nor is it pushed by a wave, nor does it turn into a wave (all of these have been tested.) As far as we can tell, it simply exists in all possible states at once, then the "observation" causes the wave function to collapse into a single discreet value.

The reason that they chose the word "observation" is because of how they tried to figure out what was going on a hundred years ago with the double slit experiment. They were confused by the interference pattern created by individual electrons (caused by the wave-like probability) and they wanted to see which slit the electron actually went through. In order to do that, they had to bounce a photon off of it to know where it was. The problem was that this act required interaction with the electron (hitting it with a photon) which collapse the wavefunction and removed the wave effect. That may be obvious, that you have to interact in order to know anything and that interaction changes things. Here's the weird part though: if the electron was not hit by a photon (meaning no detection,) it still collapsed the wave function. That's because you've eliminated some of the possibility space, which is also an interaction. You've "observed" where it isn't which is just as valid to collapse a function as "observing" where it is.

Schrodingers cat was just an analogy of how something can exist in multiple states at once unless you look. Where you know that a cat must either by physically dead or physically alive, the fact that you can't know until you look is the point, but in QM, looking changes the outcome, so you really don't know, and it does appear to exist in all states at once.

Experiments seem to show that particles exist in all states simultaneously until the probability function is broken. Einstein once quipped that "god does not play dice with the universe," and more the more modern version is "not only does god play dice, but sometimes he throws them where you can't see them."

 

Huh. So it's not that we don't KNOW why they act one way and not the other, they act all ways until something forces them to "decide?"

 

No, we have no Mathematical description or even any idea what happens at the instant of collapse of the wave function. It actually violates another QM constraint that the universe appears granular. The point of collapse is a mathematical singularity that we haven't solved yet (string theory and LQG both have descriptions but not proven.). We do know what will cause the "decision". If it's in any way possible to know the path of the particle, it will act as a particle. In laymens terms, it can even backwards propagate through time (although mathematically, no information violates causality.). Look up the delayed quantum eraser experiment if you really want to bend your mind.

Oh, and yeah, dark energy seems to be pushing space apart by adding new space. It appears to be just something that space does. We're completely clueless on it, there aren't even any mathematically sound theories. Competing calculations to the amount of energy in empty space vary between GR and QM by a factor of a googol (really) so yeah, clueless is an understatement. Most other mysteries we at least have some valid ideas. It's just a constant that appears in GR.

 

I printed this out and put it on the coffee table at work. All of us 10 people, are in software. Most of us are science types, computer science, physics, mathematics and so on. We talk a lot of science stuff, there is always someone that knows.

One of the guys (mathematics) immediately complained about the title

...and it's theoretical...

He is right isn't he. It's should be its
?
Hate to complain on a good article.

 

Who gives a shit in this case?