Giant Spinons

We study the spectrum around the "antiferromagnetic" states of the planar AdS_5/CFT_4 duality. In contrast to the familiar large-spin limit J \to \infty where each magnon momentum scales as p \sim 1/J << 1, we consider a novel "large-winding" limit in which the total momentum becomes infinitely large, \sum_j p_j \to \infty. Upon taking the limit we identify "spinon" excitations of both gauge and string theories. In particular, a (classical) string spinon turns out to be an infinite set of spiky strings, which are closely related to well-known infinite-spin strings: giant magnons. Furthermore, we show that the curious agreement of scattering phase-shifts of two spikes and that of two giant magnons can be accounted for by regarding the spinon scattering as factorised scatterings of infinitely many magnons.