Green functions and nonlinear systems: Short time expansion
arXiv:0704.1568 · doi:10.1142/S0217751X08038160
Abstract
We show that Green function methods can be straightforwardly applied to nonlinear equations appearing as the leading order of a short time expansion. Higher order corrections can be then computed giving a satisfactory agreement with numerical results. The relevance of these results relies on the possibility of fully exploiting a gradient expansion in both classical and quantum field theory granting the existence of a strong coupling expansion. Having a Green function in this regime in quantum field theory amounts to obtain the corresponding spectrum of the theory.
7 pages, 3 figures. Version accepted for publication in International Journal of Modern Physics A