Before quantum computers and quantum networks can fulfil their huge potential, scientists have got several difficult problems to overcome – but a new study outlines a potential solution to one of these problems.
As we've seen in recent research, the silicon material that our existing classical computing components are made out of has shown potential for storing quantum bits, too.
Silicon qubits are one type that physicists have managed to get more advanced and more stable over time, but there's also the question of linking them together at scale. What the new research shows is that certain defects in the silicon – known as T centers – can act as photonic (or light-based) links between qubits.
"An emitter like the T center that combines high-performance spin qubits and optical photon generation is ideal to make scalable, distributed, quantum computers," says quantum physicist Stephanie Simmons from Simon Fraser University in Canada.
"They can handle the processing and the communications together, rather than needing to interface two different quantum technologies, one for processing and one for communications."
In other words, it's a more efficient system and quite possibly one that's easier to build. The researchers report that it is the first time this kind of quantum particle activity has been observed optically in silicon – more evidence that it's a viable way forward.
There's another benefit, too: T centers emit light at the same wavelength used by current fiber communications and telecom equipment networks. That would make rolling out quantum internet technology more straightforward.
"With T centers, you can build quantum processors that inherently communicate with other processors," says Simmons.
"When your silicon qubit can communicate by emitting photons (light) in the same band used in data centers and fiber networks, you get these same benefits for connecting the millions of qubits needed for quantum computing."
The researchers produced tens of thousands of small 'micropucks' on silicon wafers, using special microscopy techniques to confirm that each of these tiny devices had a small number of T centers that could be individually addressed and controlled.
There's a lot more work to do – qubits need to be made more reliable and more accurate so they can be properly utilized – but this research gets us another significant step closer to a quantum computing future.
If that future can be based on silicon, then we already have years of manufacturing expertise and equipment to call on, and that in turn means a smoother transition to quantum computing at scale.
"By finding a way to create quantum computing processors in silicon, you can take advantage of all of the years of development, knowledge, and infrastructure used to manufacture conventional computers, rather than creating a whole new industry for quantum manufacturing," says Simmons.
The research has been published in Nature.