TY - RPRT T1 - Stability of the (2+2)-fermionic system with zero-range interaction Y1 - 2015 A1 - Alessandro Michelangeli A1 - Paul Pfeiffer AB - We introduce a 3D model, and we study its stability, consisting of two distinct pairs of identical fermions coupled with a two-body interaction between fermions of different species, whose effective range is essentially zero (a so called (2+2)-fermionic system with zero-range interaction). The interaction is modelled by implementing the the celebrated (and ubiquitous, in the literature of this field) Bethe-Peierls contact condition with given two-body scattering length within the Krein-Visik-Birman theory of extensions of semi-bounded symmetric operators, in order to make the Hamiltonian a well-defined (self-adjoint) physical observable. After deriving the expression for the associated energy quadratic form, we show analytically and numerically that the energy of the model is bounded below, thus describing a stable system. UR - http://urania.sissa.it/xmlui/handle/1963/34474 N1 - This SISSA preprint has 17 pages and recorded in PDF format U1 - 34649 U2 - Mathematics U4 - 1 U5 - MAT/07 ER -