Tiny component may be able to reach ‘quantum supremacy’

(Credit: Ola J. Joensen/U. Copenhagen)

Researchers have developed a nanocomponent that emits light particles carrying quantum information.

Less than one-tenth the width of a human hair, the miniscule component makes it possible to scale up and could ultimately reach the capabilities required for a quantum computer or quantum internet.

The authors of the new study and their colleagues have focused on developing quantum communication technology based on light circuits, known as nanophotonic circuits. Now, they’ve achieved a major advancement.

“It is a truly major result, despite the component being so tiny…”

“It is a truly major result, despite the component being so tiny,” says Leonardo Midolo, an assistant professor at the University of Copenhagen who has been working towards this breakthrough for the past five years.

The research team has invented a component, called a nanomechanical router, that emits quantum information carried by light particles (photons) and routes them into different directions inside a photonic chip. Photonic chips are like computer microchips—only, they use light instead of electrons.

The component merges nano-opto-mechanics and quantum photonics—two areas of research that, until now, have never been combined. Most spectacular of all is the size of the component, just a tenth of a human hair. It is this microscopic size that makes it so promising for future applications, researchers say.

“Bringing the worlds of nanomechanics and quantum photonics together is a way to scale up quantum technology. In quantum physics, it has been a challenge to scale systems. Until now, we have been able to send off individual photons. However, to do more advanced things with quantum physics, we will need to scale systems up, which is what this invention allows for.

“To build a quantum computer or quantum internet, you don’t just need one photon at a time, you need lots of photons simultaneously that you can connect to each another,” explains Midolo.

To exploit quantum mechanical laws to build a quantum computer or a quantum internet, scientists must integrate many nanomechanical routers in the same chips. About 50 photons are necessary to have enough power for achieving what is known as “quantum supremacy.”

According to Midolo, the new nanomechanical router makes this a realistic goal. “We have calculated that our nanomechanical router can already be scaled up to ten photons, and with further enhancements, it should be able to achieve the 50 photons needed to reach ‘quantum supremacy.'”

The invention is also a major leap forward in controlling light in a chip. Existing technology allows scientists to integrate only a few routers on a single chip due to the large device footprint. Nanomechanical routers, on the contrary, are so small that several thousand can be integrated in the same chip.

“Our component is extremely efficient. It is all about being able to emit as many photons at once, without losing any of them. No other current technique allows for this,” says Midolo.

The researchers carried out their work in the Quantum Photonics Group at the Niels Bohr Institute, which is a part of the Center for Hybrid Quantum Networks. Innovationsfonden; Villum Fonden; Danmarks Grundforskningsfond; H2020 European research Concil; Teknologi og Produktion, Det Frie Forskningsråd; Bundesministerium für Bildung und Forschung; Deutsche Forschungsgemeinschaft; Styrelsen for Forskning og Innovation funded the research.

Source: University of Copenhagen