Nonlinear amplification of instabilities with longitudinal expansion

作者：Berges Juergen^*; Boguslavski Kirill; Schlichting Soeren

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012, 85(7): 076005.

DOI：10.1103/PhysRevD.85.076005

We study the dynamics of nonequilibrium instabilities in anisotropically expanding systems. The most prominent example of such a system is the %26quot;glasma%26quot; in the context of relativistic heavy-ion collision experiments, where the expansion is a consequence of approximately boost-invariant initial conditions. Here we consider the problem of parametric resonance in scalar N-component quantum field theories with boost-invariant initial conditions, which is similar in spirit. We find that many aspects of the dynamics can be treated analytically by introducing a generalized conformal time. Primary instabilities, which are described by the linearized evolution equations, are seen to lead to a secondary regime of amplifications with strongly enhanced growth rates due to nonlinear corrections. For the secondary instabilities we present a power-counting scheme for weak coupling, and discuss their role for the question of isotropization and the establishment of an equation of state.

• 出版日期2012-4-5