In this article we formulate and discuss one particle quantum scattering theory on an arbitrary finite graph with n open ends and where we define the Hamiltonian to be (minus) the Laplace operator with general boundary conditions at the vertices. This results in a scattering theory with n channels. The corresponding on-shell S-matrix formed by the reflection and transmission amplitudes for inco...

The Kirchhoff’s theory for thin, inextensible, elastic rods with nonhomogeneous cross section is studied. The Young’s and shear moduli of the rod are considered to vary radially, and it is shown that an analytical solution for the constitutive relations can be obtained for circular cross section and constant Poisson’s ratio. We comment on possible applications of our results.

The Kirchhoff-Plateau problem concerns the equilibrium shapes of a system in which a flexible filament in the form of a closed loop is spanned by a liquid film, with the filament being modeled as a Kirchhoff rod and the action of the spanning surface being solely due to surface tension. We establish the existence of an equilibrium shape that minimizes the total energy of the system under the ph...