Interacting One-Dimensional Fermionic Symmetry-Protected Topological Phases
In free fermion systems with given symmetry and dimension, the possible topological phases are labeled by elements of only three types of Abelian groups, 0, Z[subscript 2], or Z. For example, noninteracting one-dimensional fermionic superconducting phases with S[subscript z] spin rotation and time-r...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Physical Society
2012
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| Online Access: | http://hdl.handle.net/1721.1/73874 https://orcid.org/0000-0002-9366-7925 https://orcid.org/0000-0002-5874-581X |
| Summary: | In free fermion systems with given symmetry and dimension, the possible topological phases are labeled by elements of only three types of Abelian groups, 0, Z[subscript 2], or Z. For example, noninteracting one-dimensional fermionic superconducting phases with S[subscript z] spin rotation and time-reversal symmetries are classified by Z. We show that with weak interactions, this classification reduces to Z[subscript 4]. Using group cohomology, one can additionally show that there are only four distinct phases for such one-dimensional superconductors even with strong interactions. Comparing their projective representations, we find that all these four symmetry-protected topological phases can be realized with free fermions. Further, we show that one-dimensional fermionic superconducting phases with Z[subscript n] discrete S[subscript z] spin rotation and time-reversal symmetries are classified by Z[subscript 4] when n is even and Z[subscript 2] when n is odd; again, all these strongly interacting topological phases can be realized by noninteracting fermions. Our approach can be applied to systems with other symmetries to see which one-dimensional topological phases can be realized with free fermions. |
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