Green functions and nonlinear systems: Short time expansion

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

References in corpus (6)

• Duality in Perturbation Theory and the Quantum Adiabatic Approximation
• Strongly coupled quantum field theory
• Green Function Method for Nonlinear Systems
• Strong coupling expansion for general relativity
• A strongly perturbed quantum system is a semiclassical system
• Dual perturbation expansion for a classical $\lambda {\varphi }^4$ field theory

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