Peter Richmond, Stefan Hutzler, Christine Sommer, Vladislav Sirenko

We examine the relationship between gross national income (GNI) and ‘democracy’ where the latter is quantified using an index proposed by the ‘Economist’. Countries considered to be authoritarian or undemocratic have significantly lower GNI than more democratic countries. Of especial interest for the physicist is that the relationship shows a sharp increase in gradient for GNI v democracy at a particular point and seems to be characteristic of a phase transition observed in many body gaseous systems. Introducing the notion of a social temperature and taking account of the inequality in income within societies allows the transition to be revealed more clearly.

Again by analogy with binding energy of molecules and cohesion we explore the relationship between democracy and fertility rates in societies. Hierachic or authoratarian societies have high fertilitiy rates whereas democratic socities have low fertility rates. The relationship is hyperbolic and not dissimilar to that between pressure and volume in a gas. The results raise questions raised for further attention: Is it meaningful to identify fertility rate and indeed other variables as “state variable” in the manner of physics. How will the these data change over time, for example, what will happen over time with some countries we identify as “superheated”? Should economic information feed-back into the definition of democracy index?