Short-time universal scaling and light-cone dynamics after a quench in an isolated quantum system in d spatial dimensions
Short-time universal scaling and light-cone dynamics after a quench in an isolated quantum system in d spatial dimensions
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DOI：
10.1103/physrevb.94.134311
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发表时间：
2016-10-25
影响因子：
3.7
通讯作者：
Mitra, Aditi
中科院分区：
文献类型：
--
作者：
Chiocchetta, Alessio;Tavora, Marco;Mitra, Aditi
我们研究了在 d > 2 空间维度中淬灭后，涨落对由具有 O(N) 对称性的 (phi(2))(2) 场论表示的孤立量子系统动力学的影响。采用涉及 epsilon = 4 - d 维度扩展的微扰重正化群方法来研究由弹性相移控制的预热状态内的演化。特别是，我们关注从无序初始状态到临界点的淬灭，这在演化中引入了有效的时间边界。在这个边界上，相关场获得了异常的尺度维度，而序参数及其相关性和响应函数的演化显示出普遍的老化。由于相关的激发以弹道方式传播，因此在真实空间中出现了光锥。在较长时间内，非弹性散射的开始在有效的凯尔迪什场理论中表现为长期增长的自生耗散，耗散顶点的强度提供了离开热前状态所需时间的估计。
We investigate the effects of fluctuations on the dynamics of an isolated quantum system represented by a (phi(2))(2) field theory with O(N) symmetry after a quench in d > 2 spatial dimensions. A perturbative renormalization-group approach involving a dimensional expansion in epsilon = 4 - d is employed in order to study the evolution within a prethermal regime controlled by elastic dephasing. In particular, we focus on a quench from a disordered initial state to the critical point, which introduces an effective temporal boundary in the evolution. At this boundary, the relevant fields acquire an anomalous scaling dimension, while the evolution of both the order parameter and its correlation and response functions display universal aging. Since the relevant excitations propagate ballistically, a light cone in real space emerges. At longer times, the onset of inelastic scattering appears as secularly growing self-generated dissipation in the effective Keldysh field theory, with the strength of the dissipative vertices providing an estimate for the time needed to leave the prethermal regime.