Z. Brzezniak et B. Jefferies, Characterization of one-dimensional point interactions for the Schrodingeroperator by means of boundary conditions, J PHYS A, 34(14), 2001, pp. 2977-2983
We find a new representation of all boundary conditions corresponding to th
e so-called point interactions. We show that there is one-to-one correspond
ence between one-dimensional point interactions and boundary conditions of
the form
u'(0(+))+ iu(0(+)) = eta alpha (u'(0(+)) - iu((0(+))) - eta<(<beta>)over ba
r>(u'(0(-)) + iu(0(-)))
u'(0(-)) - iu(0(-)) = eta beta (u'(0(+)) - iu(0(+))) + eta<(<alpha>)over ba
r>(u'(0(-)) + iu(0(-)))
with alpha, beta, eta is an element of C satisfying \eta\ = \alpha\(2) + \b
eta\(2) = 1.