Teil eines Buches,
String theory description of the interface free energy
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)
Zusammenfassung
A powerful tool to describe the physics of interfaces is the well known ``capillary wave'' model. It was realized a few years ago that this model is nothing else that the long range limit of the bosonic Nambu-Goto string theory.
An interesting open problem is to understand if real interfaces are described by the whole NG theory or only by its capillary wave limit. The two expressions only coincide at the first order in the $1/A$ expansion ($\sigma$ being the interface tension and $A$ the interface area).
By using standard covariant quantization of the bosonic string,
we were able to derive an exact expression for the Nambu-Goto expectation
for the interface free energy as a function of the geometry of the interface.
We then compared our predictions with a set of very accurate Monte Carlo data
for the interface free energy in the 3d Ising model.
The Nambu-Goto result turns out to describe the data much better than the simple capillary wave model in a large range of values of the interface area thus making interfaces one of the most effective realization of string inspired
models in nature.
