Large N Spectrum of two Matrices in a Harmonic Potential and BMN energies

The large N spectrum of the quantum mechanical hamiltonian of two hermitean matrices in a harmonic potential is studied in a framework where one of the matrices is treated exactly and the other is treated as a creation operator impurity in the background of the first matrix. For the free case, the complete set of invariant eigenstates and corresponding energies are obtained. When g_{YM}^2 interactions are added, it is shown that the full string tension corrected spectrum of BMN loops is obtained.