Narrow Results

The multitudinous expressions of the heat capacity possibly and impossibly appearing in ultra-low temperature thermodynamic systems are determined by using the Nernst theorem. It is found that the expression of the heat capacity possibly appearing in ultra-low temperature systems must satisfy Nernst’s theorem. Crucially, control discrimination methods are presented mathematically through which it can be judged for one new expression of the heat capacity that it possibly appears in ultra-low temperature thermodynamic systems or is fictional. These findings will contribute to enhancing our understanding of the behavior of ultra-low temperature systems.

It is found that without any additional assumptions, Nernst’s equation can be re-deduced from the experimental data obtained from the thermodynamic systems at ultra-low temperatures, which is different from the derivation processes in textbooks and literature, and consequently, the physical content included by Nernst’s equation should not be referred to as Nernst’s postulate or Nernst’s theorem. It should be renamed as the Nernst statement. This discovery will play an important role in improving the theoretical framework of thermodynamics. It can effectively prevent some artificial assumptions into the third law of thermodynamics, making it a true reflection of the objective world. It solves the awkward problem caused by using a thermodynamic theorem as the core contents of a thermodynamic law for over one hundred years.