Tensor Component Operations and Extraction

Functions are provided for operating on and extracting individual components of tensor structures.
Component[tens,q]extract the spherical tensor component tensq
Component[vec,i]extract the Cartesian vector component veci
Component[op,m,n]extract the matrix element opmnfrom an operator in the Zeeman basis
Component[dec,k]extract the spherical tensor of rank k from the tensor decomposition dec
Component[dec,k,q]extract the spherical tensor component of rank k and index q from a tensor decomposition
Components[expr]return a list of all components of a spherical tensor or matrix operator

Extracting components of tensor structures.