Researchers unveil the world’s first complete silicon quantum chip design

WHY THIS MATTERS IN BRIEF

Quantum computers promise unrivalled performance but all the chips designed so far are incompatible with today’s existing, silicon based legacy infrastructure, this breakthrough solves that and brings quantum computers with millions of Qubits within tantalising reach.

Researchers have been trying to build quantum computers for decades now but as you’d expect, trying to harness anything as exotic as quantum mechanics needs equally exotic materials, and that’s been the major stumbling block preventing us from building the world’s first true Quantum Computer.

Now though a team of engineers from the University of New South Wales (UNSW) in Australia have announced a breakthrough – they’ve overcome one of the industry’s major stumbling blocks and built a quantum logic gate using silicon, the same material that today’s computer chips are made from.

A Dive Into The Chip

The newly developed device allows two quantum bits, or qubits, to communicate and perform calculations together, which is a crucial requirement for quantum computers, but even better than that might be the fact that they’ve also figured out a way to scale the technology up to millions of qubits, and that means that building the world’s first quantum computer is now within reach, and if Rose’s Law, the quantum computing equivalent of Moore’s Law, which is now said to be running out of steam, is anything to go by, then we could quite quickly find ourselves building quantum computers that are “faster than the entire universe,” and if you think that’s impossible then you’ll have to debate that with a quantum physicist.

Today’s logic based computer chips work by storing information as binary bits, which are either in a 0 or 1 state, and while this has worked well for the past several decades it only allows a finite amount of data to be processed. Qubits, on the other hand, can be in the state of 0, 1, or both at the same time, something called Superposition, and it’s this strange phenomenon that gives quantum computers their unprecedented processing power. For example, in one experiment earlier this year Google put a logical, computer up against a D-Wave quantum computer, which some dispute whether it’s a quantum computer at all, and it was over 100 million times faster.

But qubits are funny things and if you can’t control them then all you have is a very fast computer that’s widly inaccurate, and ergo junk. But today researchers are getting increasingly good at controlling them but one of the major stumbling blocks has been getting them to communicate with each other and perform operations, something that’s essential for forming what’s known as a logic gate, the building block of all digital circuits, that takes two input values and provides a new output based on programmed logic.

Quantum logic gates have been built in the past, but they’ve all used exotic materials, which aren’t compatible with today’s silicon based computers, storage or networking infrastructure, and that’s why a silicon quantum logic gate is such a big deal.

“Because we use essentially the same device technology as existing computer chips, we believe it will be much easier to manufacture a full-scale processor chip than for any of the leading designs, which rely on more exotic technologies,” said project leader Andrew Dzurak, “this makes the building of a quantum computer much more feasible, since it is based on the same manufacturing technology as today’s computer industry.”

The challenge in building quantum logic gates is the fact that in order to get two qubits to ‘talk’ to each other they have to be within 20 to 40 nanometres of each other, and it’s this that makes controlling them incredibly difficult.

In the end though the team overcame this problem by copying the design of traditional chips where the binary bits are defined by tiny semiconductor devices known as transistors, with around a billion transistors alone on the chip in your smartphone.

Quantum bits, on the other hand, are defined by the spin of a single electron, but by reconfiguring traditional transistors to only be associated with one electron, Dzurak and his team were able to have them define qubits instead.

“We’ve morphed those silicon transistors into quantum bits by ensuring that each has only one electron associated with it. We then store the binary code of 0 or 1 on the ‘spin’ of the electron, which is associated with the electron’s tiny magnetic field,” said Menno Veldhorst, the lead author of the research, which has been published in Nature.

The team then showed that they could use metal electrodes on these transistors to control the qubits and get them to communicate with each other to create a functioning logic gate.

The researchers have already patented a design for a full scale quantum computer chip that would allow for millions of qubits and they believe they could build the first large scale prototype with in five years.

Given their staggering power it almost seems inevitable that quantum computers, when they finally emerge from the labs, will transform every industry on Earth, and with every new breakthrough, and with every new announcement we’re getting closer to that day, and that day is looking like it’s going to be sooner rather than later.