When people talk about the next-generation of computers, they're usually referring to one of two things: quantum computers – devices that will have exponentially greater processing power thanks to the addition of quantum superposition to the binary code – and optical computers, which will beam data at the speed of light without generating all the heat and wasted energy of traditional electronic computers.
Both of those have the power to revolutionise computing as we know it, and now scientists at the University of Technology, Sydney have discovered a material that has the potential to combine both of those abilities in one ridiculously powerful computer of the future. Just hold on for a second while we freak out over here.
The material is layered hexagonal boron nitride, which is a bit of a mouthful, but all you really need to know about it is that it's only one atom thick – just like graphene – and it has the ability to emit a single pulse of quantum light on demand at room temperature, making it ideal to help build a quantum optical computer chip.
Until now, room-temperature quantum emitters had only worked in a chunky, 3D material such as diamonds, which were never going to be easy to integrate onto computer chips.
"This material – layered hexagonal boron nitride (boron and nitrogen atoms that are arranged in a honeycomb structure) – is rather unique," said one of the researchers, Mike Ford. "It is atomically thin and is traditionally used as a lubricant; however upon careful processing we discovered that it can emit quantised pulses of light – single photons that can carry information.
"That’s important because one of the big goals is to make optical computer chips that can operate based on light rather than electrons, therefore operating much faster with less heat generation," he added.
So how does a pulse of light work with quantum computing? In a traditional computer system, photons – particles of light – can be used to store information by being in either vertical or horizontal polarisation.
But they can also be turned into quantum bits (or qubits) by being put into superposition – a unique quantum state where they're in both vertical and horizontal polarisation at the same time. That's a big deal for security, and also processing power.
"You can create very secure communication systems using single photons," explained team member Igor Aharonovich. "Each photon can be employed as a qubit (quantum bit, similarly to standard electronic bits), but because one cannot eavesdrop on single photons, the information is secure."
Best of all, the material just happens to also be cheap and easy to make, which means that it could be easily scaled up.
"This material is very easy to fabricate," said PhD student Trong Toan Tran. "It’s a much more viable option because it can be used at room temperature; it’s cheap, sustainable and is available in large quantities."
"Ultimately we want to build a 'plug and play' device that can generate single photons on demand, which will be used as a first prototype source for scalable quantum technologies that will pave the way to quantum computing with hexagonal boron nitride," he added.