PlanetPhysics/Laplacian in Cartesian Coordinates

The [[../LaplaceOperator/|Laplacian]] [[../QuantumSpinNetworkFunctor2/|operator]] in Cartesian coordinates is

${\mathrm{\nabla }}^2=\frac{{\partial }^2}{\partial x^2}+\frac{{\partial }^2}{\partial y^2}+\frac{{\partial }^2}{\partial z^2}$