Distance Correlations and Bose-Einstein Condensation

Abstract

The correlation effect on the molecular distance distribution in a Bose-Einstein gas is calculated as a function of volume and temperature, particularly for the case of degeneracy (condensation) of the gas. It is shown that, under certain conditions in the condensed state, the density as seen from any one molecule appears, over a rather extended region around it, to be considerably larger than the true density. This result seems to have direct relation to the fact that the low temperature modification of liquid helium has a negative coefficient of thermal expansion.