Gapless symmetry-protected topological phase of fermions in one dimension
Gapless symmetry-protected topological phase of fermions in one dimension
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 …