Membrane fuzzy sphere dynamics in plane-wave matrix model

In plane-wave matrix model, the membrane fuzzy sphere extended in the SO(3) symmetric space is allowed to have periodic motion on a sub-plane in the SO(6) symmetric space. We consider a background configuration composed of two such fuzzy spheres moving on the same sub-plane and the one-loop quantum corrections to it. The one-loop effective action describing the fuzzy sphere interaction is computed up to the sub-leading order in the limit that the mean distance r between two fuzzy spheres is very large. We show that the leading order interaction is of the 1/r7 type and thus the membrane fuzzy spheres interpreted as giant gravitons really behave as gravitons.