Structure of the Liquid-vapor Interface - A Nonperturbative Approach To the Theory of Interfacial Fluctuations

This paper is concerned with the fluctuations of the liquid-gas surface. We study the approach to the strong fluctuation regime as the strength of the external field pinning an interface is decreased. By means of a variational approach we treat self-consistently the order parameter and its correlations in three dimensions. Our numerical results show that the width of the profile increases as the external field decreases according to a logarithmic law. We relate this behavior to the capillary-wave-like excitations of the interface and discuss the limitations of the present approach.