Schmidt gaps in a long-range Kitaev chain

Abstract

The Schmidt gap for a block of spins in an infinite long-range Kitaev chain is calculated as a function of interaction range and the relative strengths of the chemical potential and hopping terms. We find that for long-ranged interactions where area law violations to the entanglement entropy occur, the Schmidt gap does not appear to close rapidly with chain length. For short-ranged interactions however, the Schmidt gap vanishes in a parameter region corresponding to an antiferromagnetic phase with gapless edge modes. These results demonstrate that the Schmidt gap can be used to distinguish quantum phases in the long-range Kitaev model.