Robust entanglement transfer through a disordered qubit ladder

Abstract

We study an entanglement transfer protocol in a two-leg ladder spin-1/2 chain in the presence of disorder. In the scenario where the on-site energies and intrachain couplings are correlated, following approximately constant proportions along the chain, we set up a scheme for high-fidelity state transfer via a particular subspace wherein effective fluctuations in the parameters ultimately depend on the degree of such correlations, rather on the disorder featured by each leg individually, accounted by a box distribution of strength W. Moreover, we find that the leakage of information out of that subspace is suppressed upon increasing W and thus the transfer fidelity, evaluated through the entanglement concurrence at the other end of the ladder, also builds up with W.