Helicity representations of the coordinate, momentum, and angular momentum operators

Sun Shu-sheng

Using the transformation matrix between the unit basis vectors in deferent orthogonal curvilinear coordinate systems,we deduce the general form of the transformation between the angular momentum operators in these coordinate systems.We give the representations of Hamilton operator  and angular momentum operators in the orthogonal curvilinear coordinate system.We discuss the transformation matrix of unit basis vectors among the spherical coordinate system,cylindrical coordinates system and rectangular coordinates system,and the transformation between the angular momentum operators.Furthermore,we discuss the treatment of 2operator in different coordinate systems.

Stephen P. Martin

Nandita Rudra

The angular momentum operator is closely related to rotation in space. The quantum mechanical definition of angular momentum differs from the classical definition r × p of angular momentum. This expression is not sufficiently general as it cannot yield spin angular momentum which does not have a classical counterpart without having any coordinate representation.