Absolute zero represents the lowest limit on the thermodynamic temperature scale, theoretically determined by extrapolating the ideal gas law. However, its physical nature remains unclear, largely due to the common misconception that temperature directly reflects the average kinetic energy of particles. A clearer understanding of absolute zero requires distinguishing between dynamic energy and the matter energy inherently stored in matter. Matter energy typically does not influence temperature measurements unless it is released from matter and transformed into dynamic energy. Dynamic energy, comprising potential, kinetic, and radiative components, constantly undergoes transformation and exchange within a system. Absolute zero corresponds to the complete absence of dynamic energy, meaning that all three elements must be simultaneously minimized. Temperature reflects the overall level of dynamic energy in a system, primarily through its radiative output, which originates largely from potential energy transitions and is therefore closely linked to the system's potential energy. Kinetic energy affects temperature only indirectly, through the internal redistribution of energy among different forms as the system approaches equilibrium.
Jerry Z. Liu (Mon,) studied this question.