Pair-wise decoherence in coupled spin qubit networks

TL;DR

This paper investigates how pairwise interactions, especially dipolar couplings, cause decoherence in spin networks like Fe8 molecules, and how low temperatures can suppress these effects, informing quantum computing design.

Contribution

It provides a detailed analysis of pairwise decoherence mechanisms in spin networks and highlights temperature effects on suppressing correlated errors.

Findings

Pairwise interactions are the main source of decoherence.

Low temperatures significantly suppress pairwise decoherence.

Implications for quantum information processing systems.

Abstract

Experiments involving phase coherent dynamics of networks of spins, such as echo experiments, will only work if decoherence can be suppressed. We show here, by analyzing the particular example of a crystalline network of Fe8 molecules, that most decoherence typically comes from pairwise interactions (particularly dipolar interactions) between the spins, which cause `correlated errors'. However at very low T these are strongly suppressed. These results have important implications for the design of quantum information processing systems using electronic spins.