Quantum state transfer through a spin chain in a multiexcitation subspace

Abstract

We investigate the quality of quantum state transfer through a uniformly coupled antiferromagnetic spin chain in a multiexcitation subspace. The fidelity of state transfer using multiexcitation 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 multiexcitation 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.