High threshold distributed quantum computing with three-qubit nodes

TL;DR

This paper demonstrates that three-qubit nodes in distributed quantum computing can achieve high error tolerance and scalability using advanced purification, even with noisy channels and decoherence, outperforming simpler or more complex node schemes.

Contribution

The authors introduce a scalable distributed quantum computing scheme using only three-qubit nodes that can tolerate high levels of noise and errors through purification techniques.

Findings

Entanglement infidelity can approach 10% with local operation infidelity of 0.1%.

The scheme outperforms prior methods in noise tolerance.

Applicable to ion traps and NV-centers in diamond.

Abstract

In the distributed quantum computing paradigm, well-controlled few-qubit `nodes' are networked together by connections which are relatively noisy and failure prone. A practical scheme must offer high tolerance to errors while requiring only simple (i.e. few-qubit) nodes. Here we show that relatively modest, three-qubit nodes can support advanced purification techniques and so offer robust scalability: the infidelity in the entanglement channel may be permitted to approach 10% if the infidelity in local operations is of order 0.1%. Our tolerance of network noise is therefore a order of magnitude beyond prior schemes, and our architecture remains robust even in the presence of considerable decoherence rates (memory errors). We compare the performance with that of schemes involving nodes of lower and higher complexity. Ion traps, and NV- centres in diamond, are two highly relevant emerging technologies.