ATTN LMNO - quantum fluctuation within a vacuum

[Kai]

Okay, lets see if I understand this right.

A vacuum is what is left over when all matter is removed, but technically its not a vacuum in the sense there's nothing there. The Void, or empty space time, is a sea of potential energy, coming and going out of existence in very short times and spaces but in great amounts. We can notice this by the effect it has on small particles such as electrons moving through the Void. Some believe quantum fluctuation in this way may have been the initial energy burst and inflation that started our universe.

How far off am I?

[LMNO]

Um... Let me get back to you on that one.  Im'a have to do some digging.

[Kai]

That bad, huh? :/

[LMNO]

Probably not, it's just a little outside my comfort zone.  I'll call for backup, we'll see what comes of it.

[Triple Zero]

Lemme try ... this is just what I heard from my friend the theoretical physicist, so I may have remembered it wrong.

So you have this vacuum and there's nothing there. But you also have quantum uncertainty, and that means there is a small statistical chance for a particle to suddenly pop into existence for a very short amount of time. Because of the fucked up ness of quantum stuff, you can see this as a particle and an anti particle, and when the two meet eachother they dissolve. The uncertainty bit just gives a very small chance that, instead of both not existing and doing this at the same spot, for a few short moments they randomly both exist at slightly separated locations.

Or something like that. It's all very weird and counter intuitive. I think of it like that quantum uncertainty sort of "borrows" a particle from the vacuum and has to pay that back with an anti particle in a way.

Now, you'd think this is a zero-sum game and in the end nothing really happens. But for some strange reason this is not the case, as the simple fact that there's a chance that this happens, and it does happen, even if in the end nothing changed, stuff that is happening causes some kind of "vacuum pressure" to appear. I have no idea what this vacuum pressure does, however.

And yes, afaik, this is one of the theories about what might have set off the Big Bang.

The only thing about your explanation that I'm not entirely sure of is the bit where you say the void is teeming with potential energy. I'm not sure if that's the case. It's teeming with vacuum pressure, but it's not that wild.

But I'm not sure. I can only be vague about this, because frankly I have no idea what I'm talking about, just rehashing what my friend told me, but since I never did the math, I can't say I really get what is going on.

I'll try to direct my friend to this thread, though.

[Kai]

I'm not quite sure what you mean by vacuum pressure.

[Kai]

When I say "potential energy", I mean "energy that has the potential to manifest as matter". It's really hard to imagine energy existing as apart from matter, but that seems to be what is happening in the case of quantum fluctuations, or otherwise it wouldn't happen. The potential energy of a vacuum then becomes something that isn't real in the measurable sense, except when it becomes manifest as short lived particles and their effects on matter.

If I'm wrong, does that mean that energy truly just comes out of nothing? Energy manifests out of nothing for a minute fraction of a second as particles and antiparticles and then is gone?

[Igor]

In addition to the position/momentum uncertainty relation, there is also an energy/time one. So a state that only exists for a short (and therefore more definite) time cannot have a definite energy.
So yes, as long as it comes and goes fast enough, energy can come from nothing.

[Kai]

If that's true, it doesn't make any fucking sense at all. 

[Igor]

It's pretty essential to quantum field theory. In QFT forces are described by particles being exchanged. So two electrons come toward each other, and by exchanging a photon, they are repelled and move off in opposite directions.

That photon is usually described as virtual. It just pops into existence long enough to perform that task and then blips out again. Apparently, some people would say that all photons are virtual, the only distinction being between a photon that gets detected and one that doesn't. Mathematically, they're all equivalent. Like in most of QM, it's our definition of reality that's weak here.

..I'm not helping much here, am I?

[Kai]

I honestly wonder if I'm even capable of understanding this stuff.

And if I'm not capable, I wonder if everyone who says they /really/ understand it isn't just fooling themselves.

[Triple Zero]

I'm not quite sure what you mean by vacuum pressure.

me neither, sorry, all I remember is that something was going on that was called vacuum pressure.

When I say "potential energy", I mean "energy that has the potential to manifest as matter".

but all energy has that potential?

[Faust]

I honestly wonder if I'm even capable of understanding this stuff.

And if I'm not capable, I wonder if everyone who says they /really/ understand it isn't just fooling themselves.

The first line of the first page of your QM notes is that we don't fully understand it, its just something that has to be accepted as some of its aspects can be observed(mathematically). And it is generally our way of interpreting it that creates the problems.

The photons coming into existence just long enough to act as the repelling force between particles is interesting because the effect of them not being canceled out must come from somewhere. If they behave like proper charges then its possible that polarization could cause a separation between the two enough to stop them canceling. But that's a stab in the dark.

[Kai]

I think I understand the Particle repultion via protons part. In that case the energy of the proton is manifest of the relationship between the two particles. However, its this "particles popping in and out of existence in a vacuum" thing that I'm having trouble with.

[Faust]

Star trek style metaphor: when you average out random noise it generally goes to zero. well the popping in and out of existence could be like the background noise upon which everything else rest, it also goes to zero when averaged