Nonlinear amplification of instabilities with longitudinal expansion
Nonlinear amplification of instabilities with longitudinal expansion
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DOI：
10.1103/physrevd.85.076005
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发表时间：
2012-04-05
影响因子：
5
通讯作者：
Schlichting, Soeren
中科院分区：
文献类型：
--
作者：
Berges, Juergen;Boguslavski, Kirill;Schlichting, Soeren
研究了各向异性扩展系统中非平衡不稳定性的动力学问题。这种系统最突出的例子是相对论重离子碰撞实验中的“玻璃”，其中的膨胀是近似助推不变初始条件的结果。在这里，我们考虑具有Boost不变初始条件的标量N分量量子场论中的参数共振问题，这在本质上是相似的。我们发现，通过引入广义共形时间，动力学的许多方面都可以被解析地处理。由线性化的演化方程描述的初级不稳定性被认为是由于非线性修正而导致具有强烈增强的增长率的次级放大区域。对于二次不稳定性，我们给出了弱耦合的功率计算方案，并讨论了它们在各向同性问题中的作用和状态方程的建立。
We study the dynamics of nonequilibrium instabilities in anisotropically expanding systems. The most prominent example of such a system is the "glasma" 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.