16   The Transformations of  S , k iand  R

 
We assume in the remaining sections that temperature is a key variable which is directly connected to many structural properties of materials, and therefore is independent of the velocity of an observer:

T' T

Given the invariance of temperature we get from section 8 for the transformations of k and R

k' jk · √  mmmm and mmm R' jR · √

The two gas constants are thus not cut from the same cloth as the speed of light  c jand the Planck constant h . It is therefore not appropriate to set the value of k jto 1, as is done in the system of natural units jwith c , h_bar jand the gravitational constant G .

 

S j=   k · ln (Ω) japplies for physical entropies, where Ω is the inverse of an invariant probability. Therefore entropy transforms the same as the Boltzmann constant k :

S' jjS · √

Entropies of information theory however are relativistically invariant !