Almost perfect transport of an entangled two-qubit state through a spin chain

TL;DR

This paper demonstrates that a modified XX spin chain model can nearly perfectly transmit entangled two-qubit states across any chain length without external control, showing robustness to imperfections and disorder.

Contribution

It introduces a simple modification to the XX model enabling high-fidelity entanglement transfer without external fields or coupling modulation.

Findings

Achieves near-perfect entanglement transfer with a simple spin chain model.

Works effectively for chains of any size and with certain imperfections.

Under some disorder scenarios, outperforms ideal noiseless cases.

Abstract

We show that using a slightly modified XX model for a spin-1/2 chain, one can transmit almost perfectly a maximally entangled two-qubit state from one end of the chain to the other one. This is accomplished without external fields or modulation of the coupling constants among the qubits. We also show that this strategy works for any size of the chain and is relatively robust to imperfections in the coupling constants among the qubits belonging to the chain. Actually, under certain scenarios of small disorder, we obtain better results than those predicted by the optimal ordered and noiseless case.