Sure, in principle everything is quantum mechanical. But try and work out how cold you'd have to be: use E = (1/2)mv^2 = Nk_B T. You won't ever get that cold because you can't decouple from the environment enough. You'll always be hit by radiation - even in space - making you so warm you can't...
If Alice and Bob always make the same measurement- e.g. same angle of a polarizing filter- then yes entanglement doesn't seem so spooky. But the state isn't determined all along, since when Alice and Bob choose the angle randomly, they find that when they chose orthogonal angles, their results...
No they can't. Entangled particles always look like spots, in particular Bob's will always look like spots regardless of what Alice does to hers. The reason is, each particle when considered in isolation appears to be in a mixed state, which means it resembles a statistical mixture of up/down...
I agree that "observer" is misleading, since when people hear "observer" they automatically think "sentient observer", hence we have crap like consciousness causes collapse and stuff. But I think it is OK to generalize the meaning of the word "observer" to include inanimate objects like...
I'm not sure what the lower case s is, I think it should be upper case, i.e. the operator defined in eqn 4.52. The components of S are the pauli matrices times hbar/2 as in 4.55.
That's right, any 1-dimensional manifold has zero intrinsic curvature. In order to calculate the Riemann tensor you have to parallel transport in two different directions, and you can't do that in one dimension - or rather your two directions are actually the same direction, so they just cancel...