Abstract
It is well-known that three-boson systems show the Efimov effect when the two-body scattering length a is large with respect to the range of the two-body interaction. This effect is a manifestation of a discrete scaling invariance (DSI). In this work we study DSI in the N-body system by analysing the spectrum of N identical bosons obtained with a pairwise gaussian interaction close to the unitary limit. We consider different universal ratios such as EN 0/E3 0 and EN 1/EN 0, with EN i being the energy of the ground (i = 0) and first-excited (i = 1) state of the system, for N ≤ 16. We discuss the extension of the Efimov radial law, derived by Efimov for N = 3, to general N. © 2013 Springer-Verlag Wien.