# Absolute zero should be impossible

1. Nov 23, 2015

### coach950

So since heat comes from atoms vibrating and moving and as they go fast heat increases and when they go slower heat decreases. If I got this right absolute zero is when they give off no heat and this would mean that the atoms are not moving at all. Well then if that is how absolute zero works then it is impossible due to Heisenberg's uncertainty principle. We could measure where they were and since they weren't moving we would know there momentum would be zero. So basically what I'm asking is that if Heisenberg's uncertainty principle is true then is absolute zero even possible.

2. Nov 23, 2015

### SteamKing

Staff Emeritus
Absolute zero does not correspond to a system with zero motion. A system at absolute zero should be defined to be in its quantum mechanical ground state. While defining "motion" in quantum mechanics is a little different than classical physics, a system like a Fermi gas with a macroscopic number of particles at zero temperature will have many particles with a "velocity" $p/m$ on the order of $10^6 m/s$, even though it is a zero entropy state. Heisenberg uncertainty is unrelated to uncertainties due to thermal effects.