New 'Quantum Modem' Could Connect the Quantum Internet

The device was developed by researchers at the Max Planck Institute of Quantum Optics.
Chris Young

A new "quantum modem" sporting a tiny mirror cabinet has been developed to act as the equivalent of a classical computing internet modem for the quantum internet.

The quantum internet is an expected evolution whose existence is still in a very early development stage and is solely reliant on advances in quantum computing. 

Nevertheless, the newly-developed quantum modem adds to the list of other quantum devices, including quantum batteries and computers that signal an oncoming revolution in computing.


A quantum modem for the future

Aside from allowing calculations that would not be possible, or would take years for a classical computer, quantum computing also has the potential to allow incredibly secure spy-proof communication via a quantum internet.

Due to their very nature, quantum computers, when and if they eventually become commercially available, will be virtually unhackable.

Though the quantum computing revolution is not actually guaranteed to take place, a quantum modem brings us a step closer to seeing it become a reality.

"In the future, a quantum internet could be used to connect quantum computers located in different places, which would considerably increase their computing power!" physicist Andreas Reiserer, from the Max Planck Institute in Germany, explained in a press release.

The new research focuses on connecting stationary qubits — quantum computing's equivalent of classical computer bits — in a quantum computer with moving qubits traveling between several of the machines. 

A miniature mirrored cabinet

The newly-developed quantum modem uses light photons to store quantum data in transit. These are precisely tuned to the infrared wavelength of laser light used in today's communication systems — this means that the system can work with existing fiber-optic networks, allowing for a smoother eventual shift to quantum technologies.

The mirror cabinet can be seen in the middle of the quantum modem device. Source: Max Planck Institute

Inside their modem, the researchers installed a miniature mirrored cabinet around a crystal made out of a yttrium silicate compound.

By using the element erbium and its electrons and cooling the system to minus 271 degrees Celsius (minus 455.8 degrees Fahrenheit), the researchers were able to get their stored resting qubits to react the way they wanted with infrared photons.

"Our system thus enables efficient interactions between light and solid-state qubits while preserving the fragile quantum properties of the latter to an unprecedented degree," the researchers wrote in their published paper.

The cooled crystal keeps the erbium atoms stable enough to force an interaction while the mirrors bounced the infrared photons around the inside of the modem thousands of times.

The mirrors essentially create tens of thousands of chances for the necessary quantum leap to occur. They make the system 60 times faster and much more efficient, the researchers explain.

A quantum leap for computing?

As with most advances in quantum technology, it will likely be a long time before we see any real-world system using the new development. We are still a long way from seeing an effective quantum computing system that could be viably mass-produced. 

However, aside from presenting a substantial step forward for a potential quantum computing revolution, the quantum modem study could also help to develop quantum processors and quantum repeaters that are able to pass data over longer distances, the researchers say.

We might be a long way away from seeing the quantum computing revolution take place, but with companies like Google and IBM claiming they've achieved quantum supremacy, and a stream of other new developments, it may not be such a large leap away from becoming reality.