Ahmed Youssef, Dirk Kreimer
We study the infrared (large separations) behavior of a massless minimally coupled scalar QFT with a quartic self-interaction in de Sitter. We show that the perturbation series in the interaction strength $\lambda$ is secular, i.e it does not lead to a uniform approximation of the solution in the infrared region. Only a non-perturbative resummation can capture the correct IR behavior. We seek to justify this picture using the Dyson-Schwinger equations in the ladder-rainbow approximation. We are able to write down an ordinary differential equation obeyed by the two-point function and perform its asymptotic analysis. Opposing a widespread belief that IR divergences are regulated through a dynamical mass generation, our work suggest an even stronger IR decay than the power-law one resulting from a mass term.
View original:
http://arxiv.org/abs/1301.3205
No comments:
Post a Comment