697 research outputs found
Rotation Symmetry-Protected Topological Phases of Fermions
We study classification of interacting fermionic symmetry-protected
topological (SPT) phases with both rotation symmetry and Abelian internal
symmetries in one, two, and three dimensions. By working out this
classification, on the one hand, we demonstrate the recently proposed
correspondence principle between crystalline topological phases and those with
internal symmetries through explicit block-state constructions. We find that
for the precise correspondence to hold it is necessary to change the central
extension structure of the symmetry group by the fermion parity.
On the other hand, we uncover new classes of intrinsically fermionic SPT phases
that are only enabled by interactions, both in 2D and 3D with four-fold
rotation. Moreover, several new instances of Lieb-Schultz-Mattis-type theorems
for Majorana-type fermionic SPTs are obtained and we discuss their
interpretations from the perspective of bulk-boundary correspondence.Comment: are welcom
Fermion Condensation and Gapped Domain Walls in Topological Orders
We propose the concept of fermion condensation in bosonic topological orders
in two spatial dimensions. Fermion condensation can be realized as gapped
domain walls between bosonic and fermionic topological orders, which are
thought of as a real-space phase transitions from bosonic to fermionic
topological orders. This generalizes the previous idea of understanding boson
condensation as gapped domain walls between bosonic topological orders. We show
that generic fermion condensation obeys a Hierarchy Principle by which it can
be decomposed into a boson condensation followed by a minimal fermion
condensation, which involves a single self-fermion that is its own
anti-particle and has unit quantum dimension. We then develop the rules of
minimal fermion condensation, which together with the known rules of boson
condensation, provides a full set of rules of fermion condensation. Our studies
point to an exact mapping between the Hilbert spaces of a bosonic topological
order and a fermionic topological order that share a gapped domain wall.Comment: 20 pages, 2-colum
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