Nonabelian Berry Phase, Yang-Mills Instanton and USp(2k) Matrix Model
  The nonabelian Berry phase is computed in the T dualized quantum mechanics obtained from the USp(2k) matrix model. Integrating the fermions, we find that each of the spacetime points X_{\nu}^{(i)} is equipped with a pair of su(2) Lie algebra valued pointlike singularities located at a distance m_{(f)} from the orientifold surface. On a four dimensional paraboloid embedded in the five dimensional Euclidean space, these singularities are recognized as the BPST instantons. 
B. Chen, H. Itoyama and H. Kihara