Close on the heels of multiple innovations in quantum computing from late last year, scientists have now created a computer chip that could be capable of handling thousands of qubits (the ‘language’ of quantum computing), compared to current technology which can handle just dozens. The chip operates at a temperature of almost absolute zero, and may pave the way for next-generation quantum computers.  

Designed by engineers hailing from The University of Sydney in collaboration with Microsoft, the chip was unveiled in research published to Nature Electronics. 

“To realise the potential of quantum computing, machines will need to operate thousands if not millions of qubits,” said Professor David Reilly, a designer of the chip and engineer for both Microsoft and the University of Sydney, in a statement.

“The world’s biggest quantum computers currently operate with just 50 or so qubits,” he said. “This small scale is partly because of limits to the physical architecture that control the qubits.” 

“Our new chip puts an end to those limits.” 

 

The chip is technically called a complementary metal-oxide-semiconductor, or CMOS for short. A CMOS chip holds a tiny bit of memory that stores the BIOS settings (a program that controls much of the background tasks) of a computer, sending out vital instructions that control vital tasks and settings. Sat in the heart of the motherboard, CMOS chips are an integral part of a working computer. 

However, building one that can handle the craziness of quantum information is a difficult task. Whereas traditional computers use bits, which is a unit of information based on binary and can either be in an ‘on’ state or an ‘off’ state, quantum computers instead use qubits. A qubit introduces a new state: both ‘off’ and ‘on’, at the same time. This creates three states instead of two, allowing for much higher amounts of data to be transferred.  

The issue with this is that quantum machines must be kept cold – really, really cold. In this design, the chip must be kept at a cool 100 millikelvin, or –273.05 degrees Celsius, which is almost absolute zero. Heat introduces errors to quantum information, so extreme cold is the only way we can accurately transfer the data. 

Also, quantum data is usually transferred by a mess of wires, which are impractical for the inside of computers. This new CMOS chip utilizes a design that requires just two cables, massively improving the output. Alongside this, the chip can be kept cool using a commercially available dilution refrigerator. 

“Our device does away with all those cables. With just two wires carrying information as input, it can generate control signals for thousands of qubits,” said Dr Kushal Das, joint inventor of the chip. 

“This changes everything for quantum computing.” 

This chip is capable of controlling thousands of qubits, breaking through the input-output bottleneck that has held back researchers until now.

There is still much more to do before we have a viable quantum computer – power draws remain high, scalability is still an issue and qubit transfer still needs fidelity improvements. However, this marks one of the most advanced quantum chips produced to date, and is a giant leap forward in the pursuit of a quantum age.