- Coherent State Path Integrals
In the earlier sections, we introduced creation and annihilation operators as alternatives to position and momenta in recasting quantum mechanics of many-particle systems. The description using creation and annihilation operators has been so far tied to the Hamiltonian framework. Just as we did earlier, it is natural to ask whether the creation and annihilation operator approach can be introduced through a Lagrangian framework. It indeed can, and it is the subject of this section known as the coherent state path integral (CSPI). We first introduce the concept in the context of a single degree of freedom.