Designing spin channel geometries for entanglement distribution

TL;DR

This paper explores various spin channel geometries for entanglement distribution between remote NV centers in diamond, utilizing matrix product operator methods to simulate open system dynamics and analyze effects of disorder and missing spins.

Contribution

It introduces the application of matrix product operator techniques to simulate large spin systems for entanglement transfer, revealing how geometry and disorder influence performance.

Findings

Long transfer times cause dephasing in few-spin systems.

Increasing the number of spins mitigates dephasing effects.

Spin ladders can outperform single spin chains under certain conditions.

Abstract

We investigate different geometries of spin-1/2 nitrogen impurity channels for distributing entanglement between pairs of remote nitrogen vacancy centers (NVs) in diamond. To go beyond the system size limits imposed by directly solving the master equation, we implement a matrix product operator method to describe the open system dynamics. In so doing, we provide an early demonstration of how this technique can be used for simulating real systems. For a fixed NV separation there is an interplay between incoherent impurity spin decay and coherent entanglement transfer: Long transfer time, few-spin systems experience strong dephasing that can be overcome by increasing the number of spins in the channel. We examine how missing spins and disorder in the coupling strengths affect the dynamics, finding that in some regimes a spin ladder is a more effective conduit for information than a single spin chain.