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Quantum engineers find a use for the hashtag at the nanoscale

1 September 2017

Dr Maja Cassidy at Microsoft's Station Q in the University of Sydney is building a quantum computer using strange quasiparticles called Majorana fermions.

Dr Maja Cassidy (left) with members of the Station Q Sydney team, including director Professor David Reilly (second left). Credit: AINST

Dr Maja Cassidy (left) with members of the Station Q Sydney team, including director Professor David Reilly (second left). Credit: AINST

In the week that the ubiquitous social media tool, the hashtag, celebrated its 10th birthday an international team of quantum physicists announced it had found a use at the nanoscale for the humble little device that has launched a million Twitter wars.

It turns out that a criss-cross pattern of semiconducting nanowires is an ideal structure in which to induce some very strange quasiparticles known as Majorana fermions.

This nano-hashtag structure at scales of a billionth of a metre should help the Majorana fermions be more easily manipulated into a topological quantum bit, or qubit: the building blocks for quantum computers.

The advantage in using Majorana fermions in qubit infrastructure is that they are predicted to be far more robust than existing qubit technology.

This means scientists developing this technology are confident it will lead to a new generation of quantum architecture allowing for a scalable, fault-tolerant universal quantum computer.

A still from an explainer video on nano-hashtags produced by Technical University Eindhoven in the Netherlands.

A still from an explainer video on nano-hashtags produced by Technical University Eindhoven in the Netherlands. 'M' marks the location of Majorana fermions.

Such an architecture is being pursued by Microsoft’s Station Q, which recently announced a multi-year partnership at the University of Sydney.

One of the researchers involved with this new research is Dr Maja Cassidy, a senior researcher at Microsoft’s Station Q Sydney, based at the University of Sydney Nanoscience Hub.

Dr Cassidy said: “Networks of nanowires are crucial to demonstrate how Majorana fermions interact through braiding. These will be a fundamental building block for topological quantum computation."

Dr Cassidy worked on the research team while she was at TU Delft in the Netherlands.

Collaborators in the research at TU Eindhoven have produced an excellent explainer video on how nano-hashtags could support a quantum architecture for Majorana fermion qubits.

The research was published in Nature at the end of August.

Read more detail on the QuTech website hosted by TNO and the Technical University Delft in the Netherlands.

Video produced by TU Eindhoven in the Netherlands.