Mass and spin for classical strings in dS3

We demonstrate that all rigidly rotating strings with center of mass at the origin of the dS(3) static patch satisfy the Higuchi bound. This extends the observation of Noumi et al. for the open GKP-like string to all solutions of the Larsen-Sanchez class. We argue that strings violating the bound end up expanding towards the horizon and provide a numerical example. Adding point masses to the open string only increases the mass/spin ratio. For segmented strings, we write the conserved quantities, invariant under Gubser's algebraic evolution equation, in terms of discrete lightcone coordinates describing kink collisions. Randomly generated strings are found to have a tendency to escape through the horizon that is mostly determined by their energy. For rapidly rotating segmented strings with mass/spin < 1, the kink collisions eventually become causally disconnected. Finally we consider the scenario of cosmic strings captured by a black hole in dS and find that horizon friction can make the strings longer.

Automated summary

This study demonstrates that rigidly rotating strings with center of mass at the origin of the dS(3) static patch satisfy the Higuchi bound, showing that strings violating the bound will expand towards the horizon. It also provides an analysis of conserved quantities under Gubser's algebraic evolution equation for segmented strings and randomly generated strings, as well as the tendency for rapidly rotating segmented strings with mass/spin < 1 to eventually have causally disconnected kink collisions. Additionally, the study explores the scenario of cosmic strings captured by a black hole in dS, finding that horizon friction can elongate the strings.