Dissipation in the 1/D expansion for planar matrix models

We consider the thermal behavior of a large number of matrix degrees of freedom in the planar limit. We work in 0 + 1 dimensions, with D matrices, and use 1=D as an expansion parameter. This can be thought of as a noncommutative large-D vector model, with two independent quartic couplings for the two different orderings of the matrices. We compute a thermal two-point correlator to O(1=D) and find that the degeneracy present at large D is lifted, with energy levels split by an amount similar to 1= p . This implies a timescale for thermal dissipation similar to p . At high temperatures dissipation is predominantly due to one of the two quartic couplings.