If we think about what the temperature is, it is a measure of internal, randomized energy in a material. Absolute zero is a point at which thermal motions stop entirely.
In classic thermos, everything stops at absolute zero. But in reality, quantum mechanics rules. We cannot ever measure the exact position or momentum of a particle with perfect certainty. (Heisenberg uncertainty principle). Thus in quantum world, every motion is governed by uncertainty. We cannot ever measure the particles as not having motion.