Scientists in the UK have made a major step in quantum computing by demonstrating that superconducting electrical circuits can be used to send information between two stores of quantum information (AFP, Reuters). The advance is detailed in two papers in this week’s Nature – one by Silanpaa and colleagues and the other by Johannes Majer and colleagues.

Silanpaa and co connected their storage mechanisms for quantum information (qubits) via a cavity in which an electromagnetic wave had been established. Majer and co did a similar thing, but using ‘virtual’ photons (“weak perturbations of their cavity’s quantum light field” according to an accompanying News and Views article, subscription required). As if quantum computing wasn’t difficult enough, another paper from last week’s Nature is also relevant, one authored by Houck et al. They detailed a ‘single-photon gun’ that can be used to generate and guide photons in an electrical circuit

What does this all mean though? Basically, for quantum computing to work we need to be able to transfer information stored in qubits to other qubits. Previously this had only been done between qubits that were (relatively) close to each other; this work shows it can be done over (relatively) large distances. Here’s what the News and Views piece makes of it all: “these papers represent confident steps towards the ultimate goal of a viable, large-scale quantum computer.”.

Yale, where many of these researchers are based, has a press release on this too.

Image: “coplanar waveguide cavity connecting two superconducting phase qubits at each end” / Michael Kemper