Abstract

I use stochastic coupled cluster techniques to gain a better understanding of electronic processes in solids. Coupled cluster can give very accurate energies in systems where many electrons interact with each other (it is able to give ”chemical accuracy”). Coupled cluster can be made as accurate but expensive as desired by including more excitations from the reference Slater determinant directly. I refer to these different levels of accuracy as ”truncation levels”. Before I will eventually consider realistic solids, I have studied two model solid system so far, the uniform electron gas and the Hubbard model. These studies indicate how truncation levels of coupled cluster perform with varying strength of electron correlation in solid systems. In the talk I will focus on the uniform electron gas and present stochastic coupled cluster results at different truncation levels and correlation to determine the required truncation levels. I will also discuss the calculation performance with more truncation levels and correlation.