# Raising, lowering and number operators for Dirac notation

Starting from this very interesting post Defining quantum-mechanical Bra and Ket operations, i would like to implement raising, lowering and number operators, taking into account that they might be non-commutative, i.e. $$a_i^\dagger a_i |n_1,\dots ,n_i, \dots \rangle \neq a_i a_i^\dagger |n_1,\dots ,n_i, \dots \rangle$$ I know that there is a package for Quantum Mechanics but I would prefer a stand-alone script.