@article {2016,
	title = {Multiplicity of self-adjoint realisations of the (2+1)-fermionic model of Ter-Martirosyan--Skornyakov type},
	number = {SISSA;65/2016/MATE},
	year = {2016},
	abstract = {We reconstruct the whole family of self-adjoint Hamiltonians of Ter-Martirosyan-
Skornyakov type for a system of two identical fermions coupled with a third particle
of different nature through an interaction of zero range. We proceed through an
operator-theoretic approach based on the self-adjoint extension theory of Krein,
Vi{\v s}iik, and Birman. We identify the explicit {\textquoteleft}Krein-Vi{\v s}ik-Birman extension param-
eter{\textquoteright} as an operator on the {\textquoteleft}space of charges{\textquoteright} for this model (the {\textquoteleft}Krein space{\textquoteright}) and
we come to formulate a sharp conjecture on the dimensionality of its kernel. Based
on our conjecture, for which we also discuss an amount of evidence, we explain the
emergence of a multiplicity of extensions in a suitable regime of masses and we re-
produce for the first time the previous partial constructions obtained by means of
an alternative quadratic form approach.},
	url = {http://urania.sissa.it/xmlui/handle/1963/35267},
	author = {Alessandro Michelangeli and Andrea Ottolini}
}
