Lubos Mitas
North Carolina State University, USA

I will present a short introduction into the electronic structure quantum Monte Carlo (QMC) based on sampling of particles coordinates. These methods typically employ fixed-node approximations to deal with the fermion signs. I will show  examples of current such calculations that encompass strongly correlated systems, molecules, ultracold atomi condensates, etc, together with insights into biases generated by the fixed nodes in general. So far, however, such QMC calculations have been limited to static, collinear treatment of electronic spins. Recently, we have developed QMC with variable spins for calculations that involve spin-orbit or other spin-dependent Hamiltonians and employs generalization of the fixed-node method called fixed-phase. Lastly, I will briefly talk about the nodes of eigenstates due to their both fundamental and practical implications for the fixed-node/phase methods.

host: Martin Gmitra