Understanding and harnessing the efficient and robust flow of information and energy in quantum networks is an important challenge for practical quantum technologies.

In the first part of this talk I will consider a wire of nitrogen impurities connecting two distant NV- centre qubits. This setup has been suggested as the fundamental building block for an quantum computing architecture [1]. Using realistic parameters and models of environmental decoherence, I will argue that such wires can indeed serve as channels for quantum information, albeit in a different way than originally proposed [2].

As the second part of the talk, I shall present a simple and intuitive explanation for the intriguing observation that optimally efficient networks are not purely quantum, but are assisted by some interaction with a ‘noisy’ classical environment. By considering the systemʼs dynamics in both the site-basis and the momentum-basis, I will argue that the effect of classical noise is to sustain a broad momentum distribution, countering the depletion of high mobility terms which occurs as energy exits from the network. I will also discuss how insights from this picture can unlock further improvements in performance when a global driving field specifically targets noise at the low mobility components [3].

Time permitting, I will finish with a discussion of how quantum interference enhances energy flow through asymmetric, noisy two site networks.

[1] Yao, Jiang, Gorshkov, Gong, Zhai, Duan, Lukin, Phys. Rev. Lett 106 040505 (2011); Yao, Jiang, Gorshkov, Maurer, Giedke, Cirac, Lukin, Nat. Comm. 3 800 (2012)

[2] Ping, Lovett, Benjamin, Gauger, Phys. Rev. Lett. 110 100503 (2013)

[3] Li, Caruso, Gauger, and Benjamin, New Journal of Physics 17, 013057 (2015)

[4] Fruchtman, Gomez-Bombarelli, Lovett, and Gauger. arXiv:1511.06302 (2015).