@article{Two-electron:4001,
      recid = {4001},
      author = {Ewing, Simon Alexander},
      title = {Variational Two-electron Reduced Density Matrix Theory of  Periodic Systems},
      publisher = {The University of Chicago},
      school = {Ph.D.},
      address = {2022-06},
      pages = {69},
      abstract = {The recovery of static correlation through electronic  structure calculations has led to manynovel insights and  more accurate prediction of chemical properties for many  molecular systems
which exhibit a high degree of  degeneracy. However, such calculations are often  prohibitively
expensive for nontrivial systems when using  wavefunction-based methods. The
use of Reduced Density  Matrix (RDM) theories can lessen the computational cost,  leading
to the possibility of computing electron structures  for larger systems that include static
correlation. Here,  the Variational 2-electron Reduced Density Matrix (V2RDM)  theory is
applied to periodic systems both in the  gamma-point representation and utilizing Brillouin
Zone  sampling, to analyze how static correlation is affected by  periodic boundary conditions
and to determine whether  static correlation is affected by the momentum of the  underlying
periodic basis functions. Additionally, the  amount of static correlation present in a system  is
quantified using an adapted form of the Von Neumann  Entropy which incorporates 3-body
correlation while  remaining size-extensive. I show that static correlation is  an important
factor in the electronic structure of periodic  materials, and that in some cases the static
correlation in  periodic materials is more significant than in their  molecular counterparts.},
      url = {http://knowledge.uchicago.edu/record/4001},
      doi = {https://doi.org/10.6082/uchicago.4001},
}