2019-03-13
10:15 at HCP F 43.4

Quantum Monte Carlo approaches to solving the Schrodinger equation

Nick Blunt

St John's College, University of Cambridge, United Kingdom

In this talk I will discuss the full configuration interaction quantum Monte Carlo (FCIQMC) method, and its use for studying problems in quantum chemistry and condensed matter physics. When solving the Schrödinger equation for realistic systems, we encounter the problem that the size of the Hilbert space grows exponentially with the number of electrons and orbitals considered, so that only very small systems can be treated exactly at the quantum level. The FCIQMC method offers one way to improve this situation by instead Monte Carlo sampling the wave function. I will introduce this Monte Carlo approach, and discuss recent developments. I will also discuss the density matrix quantum Monte Carlo (DMQMC) method, which allows an essentially exact sampling of the full density matrix at finite temperatures, allowing accurate calculation of arbitrary properties, including complex entanglement measures. This method has recently been used to provide accurate benchmarks for matter in the warm dense phase, as found in the interiors of stars and planets such as Jupiter.