Short-Range Entangled Phases of Fermions

Citation

Turzillo, Alexander Michael (2019) Short-Range Entangled Phases of Fermions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/3JR4-8G12. https://resolver.caltech.edu/CaltechTHESIS:05312019-162611521

Abstract

This thesis is an attempt to understand the physics of short-range entangled phases of fermions through several related approaches. The first angle is topological quantum field theory. We discuss the classification of interacting fermionic short-range entangled phases by spin cobordism and give an algebraic characterization of unoriented equivariant bosonic topological quantum field theories in one spatial dimension. A second tool is tensor network representation. We develop the formalism of fermionic matrix product states and use it to derive the stacking group law for one dimensional symmetry-enriched fermionic short-range entangled phases. We also study its relationship with state sum constructions of topological quantum field theories and develop a state sum construction for pin-minus theories in one spatial dimension. The third approach is topological band theory. We classify free fermionic phases enriched by a unitary symmetry in any dimension and determine the map into the interacting classification.

Thesis Files