An approximation to $δ'$ couplings on graphs

Taksu Cheon, Pavel Exner

Published 2004-04-23, updated 2004-05-31Version 2

We discuss a general parametrization for vertices of quantum graphs and show, in particular, how the $\delta'_s$ and $\delta'$ coupling at an $n$ edge vertex can be approximated by means of $n+1$ couplings of the $\delta$ type provided the latter are properly scaled.