Charge conservation protected topological phases
2013 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 87, no 16, 161103- p.Article in journal (Refereed) Published
We discuss the relation between particle number conservation and topological phases. In four spatial dimensions, we find that systems belonging to different topological phases in the presence of a U(1) charge conservation can be connected adiabatically, i.e., without closing the gap, upon intermediately breaking this local symmetry by a superconducting term. The time reversal preserving topological insulator states in two and three dimensions which can be obtained from the four-dimensional parent state by dimensional reduction inherit this protection by charge conservation. Hence, all topological insulators can be adiabatically connected to a trivial insulating state without breaking time reversal symmetry, provided an intermediate superconducting term is allowed during the adiabatic deformation. Conversely, in one spatial dimension, non-symmetry-protected topological phases occur only in systems that break U(1) charge conservation. These results can intuitively be understood by considering a natural embedding of the classifying spaces of charge conserving Hamiltonians into the corresponding Bogoliubov-de Gennes classes.
Place, publisher, year, edition, pages
2013. Vol. 87, no 16, 161103- p.
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:su:diva-89861DOI: 10.1103/PhysRevB.87.161103ISI: 000317195700001OAI: oai:DiVA.org:su-89861DiVA: diva2:621415
FunderSwedish Research Council