Pretty good state transfer of entangled states through quantum spin chains

TL;DR

This paper demonstrates that unmodulated quantum spin chains can achieve pretty good transfer of multi-qubit entangled and unentangled states, broadening the potential for quantum communication using simple, uniform spin chains.

Contribution

It proves the possibility of pretty good state transfer for any multi-particle state in uniform spin chains, extending previous single-qubit transfer results.

Findings

Pretty good transfer of multi-qubit states is achievable.

Uniform spin chains can serve as quantum channels for arbitrary states.

Results are feasible with current technology.

Abstract

The XX model with uniform couplings represents the most natural choice for quantum state transfer through spin chains. Given that it has long been established that single-qubit states cannot be transferred with perfect fidelity in this model, the notion of pretty good state transfer has been recently introduced as a relaxation of the constraints on fidelity. In this paper, we study the transfer of multi-qubit entangled and unentangled states through unmodulated spin chains, and we prove that it is possible to have pretty good state transfer of any multi-particle state. This significantly generalizes the previous results on single-qubit state transfer, and opens way to using uniformly coupled spin chains as quantum channels for the transfer of arbitrary states of any dimension. Our results could be tested with current technology.