  Few-body systems with large scattering length have universal properties that
do not depend on the details of their interactions at short distances. We study
the universal bound state properties of the four-boson system with large
scattering length in an effective quantum mechanics approach. We compute the
four-body binding energies using the Yakubovsky equations for positive and
negative scattering length. Moreover, we study the correlation between three-
and four-body energies and present a generalized Efimov plot for the four-body
system. These results are useful for understanding the cluster structure of
nuclei and for the creation of weakly-bound tetramers with cold atoms close to
a Feshbach resonance.
