On the existence and dynamics of braneworld black holes

Based on holographic arguments Tanaka and Emparan et al have claimed thatlarge localized static black holes do not exist in the one-braneRandall-Sundrum model. If such black holes are time-dependent as they propose,there are potentially significant phenomenological and theoreticalconsequences. We revisit the issue, arguing that their reasoning does not takeinto account the strongly coupled nature of the holographic theory. We claimthat static black holes with smooth metrics should indeed exist in thesetheories, and give a simple example. However, although the existence of suchsolutions is relevant to exact and numerical solution searches, such staticsolutions might be dynamically unstable, again leading to time dependence withphenomenological consequences. We explore a plausible instability, suggested byTanaka, analogous to that of Gregory and Laflamme, but argue that there is noreliable reason at this point to assume it must exist.Comment: 20 pages, 2 figures, typo corrected, references adde