The spectrum of tachyons in AdS/CFT.
Zoltan Bajnok, Nadav Drukker, Arpad Hegedus, Rafael Nepomechie, Laszlo Palla, Christoph Sieg, Ryo Suzuki
Preprint series: Journal of computational and applied mathematics, 2013-16
Abstract: We analyze the spectrum of open strings stretched between a D-brane and an anti-D-brane in planar AdS/CFT using various tools. We focus on open strings ending on two giant gravitons with different orientation in 5and study the spectrum of string excitations using the following approaches: open spin-chain, boundary asymptotic Bethe ansatz and boundary thermodynamic Bethe ansatz (BTBA). We find agreement between a perturbative high order diagrammatic calculation in N=4 SYM and the leading finite-size boundary Luscher correction. We study the ground state energy of the system at finite coupling by deriving and numerically solving a set of BTBA equations. While the numerics give reasonable results at small coupling, they break down at finite coupling when the total energy of the string gets close to zero, possibly indicating that the state turns tachyonic. The location of the breakdown is also predicted analytically.
40pp.
