A semiclassical ramp in SYK and in gravity

• DOI: 10.48550/arxiv.1806.06840
• Publication Date: 2018-01-01
• Authors: Phil Saad; Stephen H. Shenker; Douglas Stanford
• Keywords: Semiclassical physics; Black hole (networking); Saddle point; Saddle

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 large $N$ collective field description is challenge related one version of the black hole information problem. We describe candidate semiclassical explanation ramp for SYK model holes. SYK, two-replica nonperturbative saddle point fields, with action compact mode that leads linearly ramp. context, solution two-sided periodically identified under Killing time translation. discuss but resolve some puzzles arise.