Phase Structure of Black Holes and Strings on Cylinders
T. Harmark, N. A. Obers
TL;DR
This work extends the neutral, static black hole/string phase analysis on cylinders by proving that all such solutions admit the Harmark two-function ansatz and by deriving a general first-law of thermodynamics in the $(M,n)$ framework. It introduces an explicit solution-generator that unwrapps solutions to generate infinite copies, reshaping the non-uniform string and black-hole branches and constraining possible phase transitions associated with the Gregory-Laflamme instability. The paper systematically compares existing scenarios and proposes additional possibilities, aided by detailed phase-diagram reasoning and a striking near-linear TS–M behavior observed in Wiseman’s non-uniform string data. These results sharpen questions about horizon topology changes, entropy ordering, and the uniqueness of static solutions on cylinders, with potential implications for stability and cosmic censorship in higher-dimensional GR.
Abstract
We use the (M,n) phase diagram recently introduced in hep-th/0309116 to investigate the phase structure of black holes and strings on cylinders. We first prove that any static neutral black object on a cylinder can be put into an ansatz for the metric originally proposed in hep-th/0204047, generalizing a result of Wiseman. Using the ansatz, we then show that all branches of solutions obey the first law of thermodynamics and that any solution has an infinite number of copies. The consequences of these two results are analyzed. Based on the new insights and the known branches of solutions, we finally present an extensive discussion of the possible scenarios for the Gregory-Laflamme instability and the black hole/string transition.
