A semiclassical ramp in SYK and in gravity
A semiclassical ramp in SYK and in gravity
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发表时间：
2018-06
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通讯作者：
Phil Saad;S. Shenker;D. Stanford
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作者：
Phil Saad;S. Shenker;D. Stanford
在有限熵系统中，实时配分函数在后期不会衰减到零。相反，假设随机矩阵的普遍性，合适的平均值表现出增长的“斜坡”和“高原”结构。推导出这种非衰减行为在一个大的$N$集体字段的描述是一个挑战，涉及到一个版本的黑洞信息问题。我们描述了一个候选人的SYK模型和黑洞的斜坡的半经典解释。在SYK，这是一个两副本的非微扰鞍点的大$N$集体领域，零行动和紧凑的零模式，导致线性增长的斜坡。在黑洞的背景下，解决方案是一个双面黑洞，是定期确定下的杀戮时间翻译。我们讨论但不解决出现的一些难题。
In finite entropy systems, real-time partition functions do not decay to zero at late time. Instead, assuming random matrix universality, suitable averages exhibit a growing "ramp" and "plateau" structure. Deriving this non-decaying behavior in a large $N$ collective field description is a challenge related to one version of the black hole information problem. We describe a candidate semiclassical explanation of the ramp for the SYK model and for black holes. In SYK, this is a two-replica nonperturbative saddle point for the large $N$ collective fields, with zero action and a compact zero mode that leads to a linearly growing ramp. In the black hole context, the solution is a two-sided black hole that is periodically identified under a Killing time translation. We discuss but do not resolve some puzzles that arise.