Symmetry in Quantum Mechanics

Fundamental symmetries in space and time have been discussed in this chapter. The continuous symmetries include displacements in space and time and rotations in space. Discrete symmetries — space inversion (parity) and time reversal — have also been included. Operators acting on state ket space producing symmetry transformations have been derived. Discussion of important consequences of symmetries, viz. conservation laws and degeneracy, are included. Symmetry groups, their properties, group representation and their use in solving Schrödinger equation have been discussed.