Generating functionals for harmonic expectation values of paths with fixed end points: Feynman diagrams for nonpolynomial interactions
Abstract
We introduce a general class of generating functionals for the calculation of quantummechanical expectation values of arbitrary functionals of fluctuating paths with fixed end points in configuration or momentum space. The generating functionals are calculated explicitly for the harmonic oscillator with timedependent frequency, and used to derive a smearing formula for correlation functions of polynomial and nonpolynomial functions of timedependent positions and momenta. This formula summarizes the effect of quantum fluctuations, and serves to derive generalized Wick rules and Feynman diagrams for perturbation expansions of nonpolynomial interactions.
 Publication:

Physical Review E
 Pub Date:
 September 1999
 DOI:
 10.1103/PhysRevE.60.2510
 arXiv:
 arXiv:quantph/9902051
 Bibcode:
 1999PhRvE..60.2510K
 Keywords:

 03.65.w;
 Quantum mechanics;
 Quantum Physics
 EPrint:
 Author Information under http://www.physik.fuberlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fuberlin.de/~kleinert/281