Types of quantum field thories
Where zeta functions appear in physics as expressions for vacuum amplitudes, so multiple zeta functions appear in expressions for more general scattering amplitudes. The intricate combinatorics of these becomes often more tractable when re-expressing them as motivic multiple zeta values (e.g. Schlotterer-Stieberger 12).
Francis Brown, On the decomposition of motivic multiple zeta values (arXiv:1102.1310v2)
A. B. Goncharov, Galois symmetries of fundamental groupoids and noncommutative geometry (arXiv:math/0208144)
Of the superstring:
See also at motives in physics.