2022 Theses Doctoral

# Applications of Coupled Cluster Theory to Models of Extended Systems of Fermions

This thesis describes the application of coupled-cluster theory to model systems of metallic solids and cold-atom gases. First, I give an overview of both ground- and excited-state coupled cluster theory as background for the main topics in this thesis. Next, I evaluate the accuracy of several cost-saving approaches in estimating the coupled cluster correlation energy for a model metallic system, the uniform electron gas, in the complete basis set and thermodynamic limits.

After that, I present calculations of the spectral function of the uniform electron gas in these same limits, the results of which are rationalized by applying a bosonized coupled-cluster theory to an approximate, simplified Hamiltonian that couples plasmons to a structureless core hole state. Finally, I show how coupled-cluster theory captures the many-body nature of two-component Fermi gases with tunable, attractive interactions.

## Files

- Callahan_columbia_0054D_17319.pdf application/pdf 727 KB Download File

## More About This Work

- Academic Units
- Chemical Physics
- Thesis Advisors
- Berkelbach, Timothy C.
- Degree
- Ph.D., Columbia University
- Published Here
- August 3, 2022