Application of a renormalization algorithm in Hilbert space to the study   of many-body quantum systems
  We implement an algorithm which is aimed to reduce the number of basis states spanning the Hilbert space of quantum many-body systems. We test the efficiency of the procedure by working out and analyzing the spectral properties of strongly correlated and frustrated quantum spin systems. The role and importance of symmetries are investigated 
Tarek Khalil and Jean Richert