How chaos reigns in free field theories

In this talk, I will discuss a work in progress with V. Pushkarev which devoted to out-of-equilibrium dynamics and chaotic behaviour in the simplest quantum field theories — free ones. Recently, in the paper by Bianchi, Firrotta, Sonnenschein and Weissman, it was shown how one can quantitatively estimate the chaotic behaviour of certain string amplitudes. We show that similar behaviour could be observed in massive Gaussian free scalar field theories confined in finite volume after different types of quenches.