Mass and spin for classical strings in dS3

Abstract

We demonstrate that all rigidly rotating strings with center of mass at the origin of the dS3 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.

The gravitino and the swampland

“…More recently, obstructions to the limit of vanishing mass of various objects have been studied from different perspectives and related to the swampland program. For example, on backgrounds with positive energy, the consequences of the Higuchi bound [8] for integer higher spin particles and the string tower have been analysed in [9][10][11][12][13][14], while [15] proposes a general lower bound for the mass of any particle charged under an abelian symmetry. The specific case of massive spin-2 fields and of massive gravity has instead been considered in detail in [16].…”

String excitation by initial singularity of inflation

“…[9,10]. Recently, this analysis is revisited to see the consistency between the Higuchi bound and the modified Regge trajectory [11][12][13][14]. String propagation in an expanding universe has been studied in many contexts so far [15][16][17][18][19].…”