Multiplicity of self-adjoint realisations of the (2+1)-fermionic model of Ter-Martirosyan--Skornyakov type
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Date
2016-12
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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 Kreĭn, Višik, and Birman. We identify the explicit ‘Kreĭn-Višik–Birman extension parameter’ as an operator on the ‘space of charges’ for this model (the ‘Kreĭn space’) 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 reproduce for the first time the previous partial constructions obtained by means of an alternative quadratic form approach.
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Point interactions, Singular perturbations of the Laplacian, Self-adjoint ex- tensions, Kreĭn-Višik-Birman theory, Ter-Martirosyan{Skornyakov operators, Fermionic models of zero-range interactions