Excitations and stability of weakly interacting Bose gases with multibody interactions

We consider weakly interacting bosonic gases with local and nonlocal multibody interactions. By using the Bogoliubov approximation, we first investigate contact interactions, studying the case in which the interparticle potential can be written as a sum of Nbody \ensuremath{\delta}interactions and then considering general contact potentials. Results for the quasiparticle spectrum and the stability are presented. We then examine nonlocal...