Momentum of a stationary particle/wave?

[DarMM]

Not quite... but the context for the quote goes back to #22 of the thread.

I'm still not quite sure what you mean, is it simply that the particle has no position or momentum it just imprints one on the device?

 

[bob012345]

Not "any" interaction, but "any thermodynamically irreversible" interaction. Yes, and that's why Schrödinger's cat isn't in a superposition of dead and alive before we open the box - the cat is continuously interacting irreversibly with its environment, and this is generally the case for all the macroscopic objects around us. The phenomenon is called "decoherence", and it explains why the macroscopic world generally behaves classically. The particle in a box is a different situation altogether; it is interacting only with the square-well potential, reversibly.

You can google for "quantum decoherence", although the math might be a bit daunting. David Lindley's book "Where does the weirdness go" is a layman-friendly overview worth reading if you don't want to take on the math.

Thanks I've heard of it. It's what keeps my brain from already knowing everything to knowing almost nothing...:)