Events in Physics

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).