Effect of perturbations on information transfer in spin chains

TL;DR

This paper studies how various perturbations, such as fabrication defects and input operation imperfections, affect the quality of quantum information transfer in spin chains, especially for entangled and unentangled states.

Contribution

It analyzes the impact of realistic perturbations on quantum state transfer in spin chains, including multiple excitation transfer and entanglement creation, providing insights into robustness.

Findings

Perturbations reduce transfer fidelity.

Imperfect input operations affect entanglement transfer.

Multiple excitation transfer remains feasible under certain conditions.

Abstract

Spin chains have been proposed as a reliable and convenient way of transferring information and entanglement in a quantum computational context. Nonetheless, it has to be expected that any physical implementation of these systems will be subject to several perturbative factors which could potentially diminish the transfer quality. In this paper, we investigate a number of possible fabrication defects in the spin chains themselves as well as the effect of non-synchronous or imperfect input operations, with a focus on the case of multiple excitation/qubit transfer. We consider both entangled and unentangled states, and in particular the transfer of an entangled pair of adjacent spins at one end of a chain under the mirroring rule and also the creation of entanglement resulting from injection at both end spins.