How to Counteract Systematic Errors in Quantum State Transfer

TL;DR

This paper introduces encoding and decoding methods to correct systematic errors in quantum state transfer over spin chains, enabling perfect transfer despite low error rates by local operations at chain ends.

Contribution

It presents novel encoding and decoding procedures that recover perfect quantum state transfer from systematic errors using only local operations at the chain ends.

Findings

Encoding and decoding regions grow linearly with error size.

Errors can be identified through local actions at chain ends.

Methods enable perfect transfer despite low systematic errors.

Abstract

In the absence of errors, the dynamics of a spin chain, with a suitably engineered local Hamiltonian, allow the perfect, coherent transfer of a quantum state over large distances. Here, we propose encoding and decoding procedures to recover perfectly from low rates of systematic errors. The encoding and decoding regions, located at opposite ends of the chain, are small compared to the length of the chain, growing linearly with the size of the error. We also describe how these errors can be identified, again by only acting on the encoding and decoding regions.