I am wondering if beyond physical interpretation, the one dimensional contact interactions (self-adjoint extensions of the the free hamiltonian when defined everywhere except at the origin) have a geometric interpretation along the lines of non commutative geometry, Lipzchitz distance, etc.

Particulatly some extensions (such as Albeverio-Holden pseudodelta) seen as if we have just cut a segment of lenght $l$ from the free solution and then just pasted the half-lines. So in some sense they could be argued to be just the free solution over two half-lines separated a distance $l$.

Still, the full set of extensions is four parametric, so it is not clear to me if the rest of the parameters have a geometric interpretation, or even if this one can be translated to a Lipzchitz distance. Also, in NCG sometimes the separation is linked to Higgs potential, definitely not to self-adjoint extensions; I would be surprised if having a connection between both concepts, should I?

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