Overpopulated gauge fields on the lattice
Overpopulated gauge fields on the lattice
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DOI：
10.1103/physrevd.86.074006
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发表时间：
2012-03
影响因子：
5
通讯作者：
J. Berges;S. Schlichting;D. Sexty
中科院分区：
文献类型：
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作者：
J. Berges;S. Schlichting;D. Sexty
从初始超布居数出发，研究了SU(2)纯规范理论的非平衡动力学，其中强的经典规范场用一个动量标度Q_S来描述，经典统计格子模拟表明，在中间时间快速演化到指数为3/2的近似标度行为。值得注意的是，标度指数的值可以理解为在随时间变化的背景场存在的情况下，来自领先的O(g^2)贡献。这种现象与微弱的波动湍流有关，它描述了一种朝向更高动量的能量级联。这一特殊方面与标量理论中观察到的非常相似，在标量理论中，由于依赖于时间的玻色凝聚体的存在，产生了有效的立方相互作用。
We study nonequilibrium dynamics of SU(2) pure gauge theory starting from initial over-population, where intense classical gauge fields are characterized by a single momentum scale Q_s. Classical-statistical lattice simulations indicate a quick evolution towards an approximate scaling behavior with exponent 3/2 at intermediate times. Remarkably, the value for the scaling exponent may be understood as arising from the leading O(g^2) contribution in the presence of a time-dependent background field. The phenomenon is associated to weak wave turbulence describing an energy cascade towards higher momenta. This particular aspect is very similar to what is observed for scalar theories, where an effective cubic interaction arises because of the presence of a time-dependent Bose condensate.