“…This program has met with apparent success in the BMN limit [12,13,14], where the operators are very close to being BPS. It has also been successful, to a point, in the long wave-length limit, where the eigenvalues of the dilatation operator have been shown to match the string predictions at the one-loop level [15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40], and in some cases up to two loop order [42,24,43,44,45], although there is a mismatch at three loop order [46,42,47,44]. Both the BMN limit and the long wave-length limit can be treated using a semiclassical analysis [48,49], with expansion parameter λ/L 2 , where λ is the 't Hooft parameter and quantum corrections are suppressed by 1/L.…”