Multi-configurational Symmetrized Projector Quantum Monte Carlo Studies of excited states of the Hubbard model

We develop a novel multi-configurational Symmetrized Projector Quantum Monte Carlo (MSPQMC) method to calculate excited state properties of Hubbard models. We compare the MSPQMC results for finite Hubbard chains with exact results (where available) or with Density Matrix Renormalization Group (DMRG) results for longer chains. The energies and correlation functions of the excited states are in good agreement with those obtained from the alternate techniques.