ABSTRACT
In the present chapter, before discussing the mechanical operators, operator has been lucidly defined and examples are cited for its clear understanding. It includes linear and non-linear operator, commutator and commutation, and Hermitian operator and its properties. It also consists of Schmidt orthogonalisation, del and del2 operators, linear momentum operator and it applications, angular momentum vector and commutation, and angular momentum in spherical polar co-ordinates. This chapter also provides a good discussion regarding ladder operator, Hamiltonian operator and its commutation, and relation of angular momentum operators with Hamiltonian operators. It also discusses projection operator clearly and solution of problem related to projection operator. The properties of projection operator have also been given. Suitable references have also been provided for the consultation. A large number of problems and their solutions relating to different operators have also been cited. Questions on concepts have also been provided for exercise purposes. The readers are advised to solve these problems for better understanding.
