AUTHOR=Glasser M. L. 

TITLE=A Note on the Exact Green Function for a Quantum System Decorated by Two or More Impurities

JOURNAL=Frontiers in Physics

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2019.00007

DOI=10.3389/fphy.2019.00007

ISSN=2296-424X

ABSTRACT=<p>The exact Green function is constructed for a quantum system, with known Green function, which is decorated by two delta function impurities. It is shown that when two such impurities coincide they behave as a single singular potential with combined amplitude. The results are extended to N impurities and higher dimensions.</p>