@article {2015,
	title = {Stability of the (2+2)-fermionic system with zero-range interaction},
	number = {SISSA;29/2015/MATE},
	year = {2015},
	note = {This SISSA preprint has 17 pages and recorded in PDF format},
	abstract = {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.},
	url = {http://urania.sissa.it/xmlui/handle/1963/34474},
	author = {Alessandro Michelangeli and Paul Pfeiffer}
}
