Handling Excited States on the Lattice: The GEVP Method
  High-precision calculations of hadron spectroscopy are a crucial task for Lattice QCD. State-of-the-art techniques are needed to disentangle the contributions from different energy states, such as solving the generalized eigenvalue problem (GEVP) for zero-momentum hadron correlators in an efficient way. We review the method and discuss its application in the determination of the $B_s$-meson spectrum using (quenched) nonperturbative HQET at order $1/m_b$. 
Tereza Mendes
hep-lat hep-ph