Conserved quantities of SU(2)-invariant interactions for correlated   fermions and the advantages for quantum Monte Carlo simulations
  In the context of realistic calculations for strongly-correlated materials with $d$- or $f$-electrons the efficient computation of multi-orbital models is of paramount importance. Here we introduce a set of invariants for the SU(2)-symmetric Kanamori Hamiltonian which allows to massively speed up the calculation of the fermionic trace in hybridization-expansion continuous-time quantum Monte Carlo algorithms. As an application, we show that, exploiting this set of good quantum numbers, the study of the orbital-selective Mott-transition in systems with up to seven correlated orbitals becomes feasible. 
Nicolaus Parragh, Alessandro Toschi, Karsten Held and Giorgio   Sangiovanni
cond-mat.str-el cond-mat.supr-con