BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Ben Craps (VUB) DTSTART:20210112T110000Z DTEND:20210112T120000Z DTSTAMP:20260513T204324Z UID:CCTP_HEP/31 DESCRIPTION:Title: Slow scrambling in extremal BTZ and microstate geometries\nby Ben Cr aps (VUB) as part of CCTP HEP Seminars\n\n\nAbstract\nOut-of-time-order co rrelators (OTOCs) that capture maximally chaotic properties of a black hol e are determined by scattering processes near the horizon. This prompts th e question to what extent OTOCs display chaotic behaviour in horizonless m icrostate geometries. This question is complicated by the fact that Lyapun ov growth of OTOCs requires nonzero temperature\, whereas constructions of microstate geometries have been mostly restricted to extremal black holes . We compute OTOCs for a class of extremal black holes\, namely maximally rotating BTZ black holes\, and show that on average they display "slow scr ambling"\, characterized by cubic (rather than exponential) growth. Superp osed on this average power-law growth is a sawtooth pattern\, whose steep parts correspond to brief periods of Lyapunov growth associated to the non zero temperature of the right-moving degrees of freedom in a dual conforma l field theory. Next we study the extent to which these OTOCs are modified in certain "superstrata"\, horizonless microstate geometries correspondin g to these black holes. Rather than an infinite throat ending on a horizon \, these geometries have a very deep but finite throat ending in a cap. We find that the superstrata display the same slow scrambling as maximally r otating BTZ black holes\, except that for large enough time intervals the growth of the OTOC is cut off by effects related to the cap region\, some of which we evaluate explicitly.\n LOCATION:https://researchseminars.org/talk/CCTP_HEP/31/ END:VEVENT END:VCALENDAR