26/09/2025
absolute zero (0 K), the situation is special:
Classical view: In classical physics, gas molecules would have no kinetic energy at all. They would be completely at rest.
Quantum view: In quantum mechanics, even at absolute zero, molecules (or atoms) retain a minimum energy called zero-point energy.
This energy comes from the Heisenberg Uncertainty Principle: you cannot simultaneously have both exact zero momentum and exact position.
Therefore, molecules still possess some residual vibrational energy (for solids) or ground-state energy in their quantum states.
At absolute zero, gas molecules have zero-point energy (quantum mechanical energy that cannot be removed), but they have no thermal kinetic energy in the classical sense.
