We develop superstring bit models, in which the lightcone transverse coordinates in D spacetime dimensions are replaced with d = D −2 double-valued “flavor” indices xk → fk = 1, 2; k = 2, . . . , d + 1. In such models the string bits have no space to move. Let-ting each string bit be an adjoint of a “color” group U(N), we then analyze the physics of ’t Hooft’s limit N → ∞, in which closed chains of many string bits behave like free lightcone IIB superstrings with d compact coordinate bosonic worldsheet fields xk, and s pairs of Grassmann fermionic fields θL,Ra, a = 1, . . . , s. The coordinates xk emerge because, on the long chains, flavor fluctuations enjoy the dynamics of d anisotropic Heisenberg spin chains. It is well-known that the low energy excitations of a many-spin Heisenberg chain are identical to those of a string worldsheet coordinate compactified on a circle of radius Rk, which is related to the anisotropy parameter −1 ≤ Δk ≤ 1 of the corresponding Heisenberg system. Furthermore there is a limit of this parameter, Δk → ±1, in which Rk → ∞. As noted in earlier work [Phys. Rev.D 89 (2014) 105002], these multi-string-bit chains are strictly stable at N = ∞ when d < s and only marginally stable when d = s. (Poincaré supersymmetry requires d = s = 8, which is on the boundary between stability and instability.)
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