Conventional computers use bits, which can be either zero or one at a time, to store information and to perform calculations. Quantum computers, on the other hand, use qubits for those tasks, which improve over conventional bits because they can also be an arbitrary combination of zero and one at the same time, a quantum physics phenomenon. This improvement is expected to spark a revolution in areas such as climate and pharmaceutical research.
Nowadays, several architectures are being tested around the world in the race for building the first quantum computer processor with millions of qubits instead of just a few of them. Those include silicon spin qubits, ion traps, superconducting loops, diamond vacancies and topological qubits. Unfortunately, in all of those architectures, qubits are currently extremely fragile and prone for calculation error, and even quantum processors with just a few of them are too big for mass manufacturing. But according to researchers from the University of New South Wales (UNSW), a new chip design has both problems solved.
As already reported here at Neowin, UNSW researchers are favoring the silicon spin qubit approach to quantum computing, mainly because it enables them to reuse the currently available technology developed for silicon microprocessors. By following this path, they have recently published a paper in the journal Nature Communications announcing a new chip design based on CMOS (complementary metal-oxide-semiconductor) for performing calculations.
The new UNSW silicon quantum processor consists of a vast two-dimensional array of qubits and uses conventional silicon transistors to control the qubit's spins and two-qubit logic interactions. As stated by Dr. Menno Veldhorst, lead author of the paper:
By selecting electrodes above a qubit, we can control a qubit's spin, which stores the quantum binary code of a 0 or 1. And by selecting electrodes between the qubits, two-qubit logic interactions, or calculations, can be performed between qubits.
The team of researchers claims it is the first time all of the key components needed for quantum computing are made available in a single chip. Furthermore, the chip's architecture includes error-correcting codes that rely on multiple qubits storing a single piece of data, which were designed specifically for spin qubits.
The team from UNSW expects some changes will be necessary in the chip's design as it is prepared for manufacturing. Either way, they are already proud of how fast they have achieved this milestone, since it was only two years ago when they first created a two-qubit logic gate, demonstrating how quantum calculations could be done in a silicon-based chip.