Quantum Mechanics and Omniscience

[Pulsar]

I suppose that determining the precise position of the particle within its wavelength is the problem. At least thats the only thing I can conceive of as a problem. So if we know precisely how fast a particle is moving, we can only know that it is somewhere within its wave-length - i.e. for gamma rays for example could only be pinpointed to within 10^-5 nm?

Yes, I think that's more or less it. These diffraction patterns only occur if the slits have about the same width as the particle wavelength. The initial probability to find a particle is only significant in a region with the same order of magnitude as its wavelength. But the longer the beam, the more this uncertainty propagates, so a beam would widen. There was a small section on laser beams in that wiki article about diffraction.

 

[Sparky]

Quantum mechanics is pretty sweet.

I like quantum tunneling I mean how counter-intuitive is it to say that a particle with x energy, confronted with an energy barrier of x+y (where y > 0 obviously), has a small but finite chance of overcoming the barrier.

Also one of the major problems with nanotech at the moment is that particles spontaneously come into existence along with their antiparticle and then annihilate eachother within a fraction of a second. This creates a (relatively) significant amount of friction when you are building on the scale of a few hundred or thousand atoms.....

 

[Ozymandyus]

Also one of the major problems with nanotech at the moment is that particles spontaneously come into existence along with their antiparticle and then annihilate eachother within a fraction of a second. This creates a (relatively) significant amount of friction when you are building on the scale of a few hundred or thousand atoms.....

Really? Something about this doesn't sound right... - they can't possibly 'spontaneously' come into existence, as when they annihilate each other they release energy (usually in the form of photons I believe). So creating a particle-antiparticle pair would also take energy. That energy could certainly effect the nano-tech, but friction? I'll have to look into this.

 

[Sparky]

Sorry. My explanation was very poor. It seems that I had most of it wrong. What I was trying to explain was the Casimir effect. It is explained in this link:

http://en.wikipedia.org/wiki/Casimir_effect

As you can see, it causes surfaces to be drawn together and since it only is significant at small distances, this poses a serious barrier to nanotechnology.