Many-body Majorana-like zero modes without gauge symmetry breaking
journal contributionposted on 08.10.2021, 14:10 by V Vadimov, T Hyart, JL Lado, M Möttönen, Tapio Ala-NissilaTapio Ala-Nissila
Topological superconductors represent one of the key hosts of Majorana-based topological quantum computing. Typical scenarios for one-dimensional (1D) topological superconductivity assume a broken gauge symmetry associated to a superconducting state. However, no interacting 1D many-body system is known to spontaneously break gauge symmetries. Here, we show that zero modes emerge in a many-body system without gauge symmetry breaking and in the absence of superconducting order. In particular, we demonstrate that Majorana zero modes of the symmetry-broken superconducting state are continuously connected to these zero-mode excitations, demonstrating that zero-bias anomalies may emerge in the absence of gauge symmetry breaking. We demonstrate that these many-body zero modes share the robustness features of the Majorana zero modes of symmetry-broken topological superconductors. We further show that the interface between the interacting model and a 1D topological superconductor does not support Majorana modes. We introduce a bosonization formalism to analyze these excitations and show that a ground state analogous to a topological superconducting state can be analytically found in a certain limit. Our results demonstrate that robust Majorana-like zero modes may appear in a many-body system without gauge symmetry breaking, thus introducing a family of protected excitations with no single-particle analogs.
Academy of Finland projects (Grants No. 331342 and No. 336243) and its Centre of Excellence in Quantum Technology (QTF) (Grant No. 336810)
European Research Council under Grant No. 681311 (QUESS)
Foundation for Polish Science through the IRA Programme co-financed by EU within SG OP
- Mathematical Sciences