According to the principles of quantum mechanics, atoms and other particles are in a state of constant motion, even at extremely low temperatures. This motion is known as thermal motion or atomic motion.
At temperatures above absolute zero (-273.15 degrees Celsius or 0 Kelvin), atoms possess kinetic energy and are in constant motion. This motion arises from the inherent energy associated with the particle's wave-like nature. At higher temperatures, the atoms move more vigorously and have greater kinetic energy, resulting in faster and more random motion.
However, as the temperature approaches absolute zero, the motion of atoms slows down significantly. At absolute zero, atoms would theoretically come to a complete stop and have no kinetic energy. This is known as the ground state or zero-point energy. Achieving absolute zero in practice is extremely challenging, and it is practically impossible to eliminate all motion from a system.
Even at very low temperatures close to absolute zero, atoms still exhibit residual motion due to quantum effects. This motion is referred to as zero-point motion or quantum fluctuations. It arises from the Heisenberg uncertainty principle, which states that the position and momentum of a particle cannot be precisely known simultaneously.
In summary, based on our current understanding of physics, atoms are always in motion due to their inherent quantum nature, even though their motion slows down at very low temperatures.