Perfect quantum transport in arbitrary spin networks

TL;DR

This paper introduces methods for achieving perfect quantum information transfer in arbitrary spin networks by using weak coupling and control techniques, enabling high-fidelity transfer even with imperfect or natural networks.

Contribution

The authors propose a novel approach for perfect quantum transport in arbitrary spin networks using weak coupling and minimal control, applicable to engineered and natural systems.

Findings

Achieved perfect quantum state transfer with limited control resources.

Demonstrated robustness of the method in arbitrary network topologies.

Proposed practical implementation with nitrogen vacancy centers.

Abstract

Spin chains have been proposed as wires to transport information between distributed registers in a quantum information processor. Unfortunately, the challenges in manufacturing linear chains with engineered couplings has hindered experimental implementations. Here we present strategies to achieve perfect quantum information transport in arbitrary spin networks. Our proposal is based on the weak coupling limit for pure state transport, where information is transferred between two end-spins that are only weakly coupled to the rest of the network. This regime allows disregarding the complex, internal dynamics of the bulk network and relying on virtual transitions or on the coupling to a single bulk eigenmode. We further introduce control methods capable of tuning the transport process and achieve perfect fidelity with limited resources, involving only manipulation of the end-qubits. These strategies could be thus applied not only to engineered systems with relaxed fabrication precision, but also to naturally occurring networks; specifically, we discuss the practical implementation of quantum state transfer between two separated nitrogen vacancy (NV) centers through a network of nitrogen substitutional impurities.