M-theory on Less Supersymmetric PP-Waves
  There are fractionally supersymmetric pp-waves in 11 dimensional supergravity. We study the corresponding supersymmetric Yang-Mills matrix dynamics for M-theory and find its superalgebra and vacuum equations. We show that the ground state energy of the Hamiltonian with nontrivial dynamical superysmmetry can be zero, positive or negative depending on parameters. 
Kimyeong M. Lee