Path-integral approach to Casimir effect with infinitely thin plates

When studying the Casimir effect in a quantum field theory setting, one can impose the boundary conditions by adding appropriate Dirac- <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>δ</a:mi> </a:math> functions to the path integral. In this paper, the limits of this approach are explored under different boundary conditions.