Alavi 2019

Ali Alavi (Max Planck Institute for Solid State Research)
Recent Progress with Full Configuration Interaction Quantum Monte Carlo
26 November 2019 (Tue) 15:30-16:30 Science and Technology Research Building #4 807 Seminar Room
We will report on recent developments in the FCIQMC methodology over the past year. Firstly, we have developed an Adaptive-shift method to unbias for initiator error. The method will be derived, and results will be shown on some medium size molecules, showing in particular that the methodology not only achieves essentially exact (ie FCI-level) results, but that it also largely removes the dependence of the initiator method on the initiator parameter. Second, we will report on implementing the full Jastrow-factorised, similarity-transformed, Hamiltonian, including all 3-body terms, with applications to atoms and small molecules. The FCIQMC method is shown to be effective in handling the non-Hermitian nature of the problem. Finally, we have implemented a spin-adapted version of FCIQMC based on the Unitary Group Approach. We will briefly outline this development, which allows us to target specific spin states in strongly correlated systems.