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

Abstract

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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.

Keywords

• quantum green function
• delta function potential
• contact interaction
• Schroedinger equation
• quantum graph
• 02.30Gp