SciPost Phys. 10, 148 (2021) ·
published 18 June 2021
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· pdf
We gauge the fermion parity symmetry of the Kitaev chain. While the bulk of
the model becomes an Ising chain of gauge-invariant spins in a tilted field,
near the boundaries the global fermion parity symmetry survives gauging,
leading to local gauge-invariant Majorana operators. In the absence of
vortices, the Higgs phase exhibits fermionic symmetry-protected topological
(SPT) order distinct from the Kitaev chain. Moreover, the deconfined phase can
be stable even in the presence of vortices. We also undertake a comprehensive
study of a gently gauged model which interpolates between the ordinary and
gauged Kitaev chains. This showcases rich quantum criticality and illuminates
the topological nature of the Higgs phase. Even in the absence of
superconducting terms, gauging leads to an SPT phase which is intrinsically
gapless due to an emergent anomaly.
