2020/10/31 by Umberto Borla, Ruben Verresen, Jeet Shah +1 · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.quant-gas #hep-lat #hep-th #quant-ph
paper · pdf · doi:10.21468/scipostphys.10.6.148
published as SciPost Phys. 10, 148 (2021) · V2. 6 figures in the main text, 2 figures in the appendix
arxiv created 2021/05/19 · arxiv updated 2021/06/23
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.