Surface tension, hydrophobicity, and black holes: The entropic connection.

The geometric entropy arising from partitioning space in a fluid " field theory " is shown to be linearly proportional to the area of an excluded region. The coefficient of proportionality is related to surface tension by a thermodynamic argument. Good agreement with experimental data is obtained for a number of fluids. The calculation employs a density matrix formalism developed previously for studying the origin of black hole entropy. This approach may lead to a practical new technique for the evaluation of thermodynamic quantities with important entropic components.