A Gapless Symmetry-Protected Topological Phase of Fermions in One Dimension
Abstract
We consider a one-dimensional, time-reversal-invariant system with attractive interactions and spin-orbit coupling. Such a system is gapless due to the strong quantum fluctuations of the superconducting order parameter. However, we show that a sharply defined topological phase with protected, exponentially localized edge states exists. If one of the spin components is conserved, the protection of the edge modes can be understood as a consequence of the presence of a spin gap. In the more general case, the localization of the edge states arises from a gap to single particle excitations in the bulk. We consider specific microscopic models and demonstrate both analytically and numerically (using density matrix renormalization group calculations) that they can support the topologically non-trivial phase.
Keywords
Cite
@article{arxiv.1502.02037,
title = {A Gapless Symmetry-Protected Topological Phase of Fermions in One Dimension},
author = {Anna Keselman and Erez Berg},
journal= {arXiv preprint arXiv:1502.02037},
year = {2015}
}