Abstract
We present a computation of the coherent state path integral for a generic linear system using “functional methods” (as opposed to discrete time approaches). The Gaussian phase space path integral is formally given by a determinant built from a first-order differential operator with coherent state boundary conditions. We show how this determinant can be expressed in terms of the symplectic transformation generated by the (in general, time-dependent) quadratic Hamiltonian for the system. We briefly discuss the conditions under which the coherent state path integral for a linear system actually exists. A necessary—but not sufficient—condition for existence of the path integral is that the symplectic transformation generated by the Hamiltonian is (unitarily) implementable on the Fock space for the system.
- Received 30 March 2005
DOI:https://doi.org/10.1103/PhysRevD.72.025004
©2005 American Physical Society