Quantum state transfer through a spin chain in a multi-excitation subspace

TL;DR

This paper explores quantum state transfer in a spin chain within a multi-excitation subspace, demonstrating high fidelity comparable to ground state protocols and revealing that fidelity depends mainly on the number of excitations.

Contribution

It introduces a novel understanding of multi-excitation state transfer fidelity, showing independence from excitation order and simplifying the preparation process.

Findings

Fidelity in multi-excitation transfer matches ground state protocols.

Fidelity depends only on the number of excitations, not their order.

Proposes a low-effort quantum communication scheme.

Abstract

We investigate the quality of quantum state transfer through a uniformly coupled antiferromagnetic spin chain in a multi-excitation subspace. The fidelity of state transfer using multi-excitation channels is found to compare well with communication protocols based on the ground state of a spin chain with ferromagnetic interactions. Our numerical results support the conjecture that the fidelity of state transfer through a multi-excitation subspace only depends on the number of initial excitations present in the chain and is independent of the excitation ordering. Based on these results, we describe a communication scheme which requires little effort for preparation.