Microsoft claims breakthrough in quantum computing with Gooseberry chip and cryo-computing core

The company says its new system is a leap ahead from previous technology

A joint team of researchers from Microsoft and the University of Sydney have announced a novel breakthrough in the field of quantum computing that allows control of thousands of qubits at very low temperatures.

The company says it has developed a cryogenic quantum control platform that uses specialised CMOS circuits to take digital inputs and generate many parallel qubit control signals. This control platform is powered by a new quantum control chip called Gooseberry, which sits next to the quantum device and resolves many issues with I/O common to quantum computers.

The researchers also claim that they have created the first general-purpose cryo-compute core, which performs the necessary computations to determine the instructions sent to Gooseberry chip which, in turn, feeds voltage pulses to the qubits.

The concept of quantum computers was first theorised in 1980s, although quantum technology developed at a relatively slow pace over the past three decades.

Quantum computers are fundamentally different from classical computers. In quantum computers, the basic building blocks are quantum bits (or qubits) which are used to store information. These qubits are described as the superpositions of 0 and 1 states - spin states can be 0 or 1 or somewhere in between, whereas classical computers use switches that are either 1 or 0.

For a quantum computer to work properly, qubits must remain 'entangled' with each other, meaning that the state of one qubit instantaneously affects the state of another qubit, even when they are physically separated from each other.

A big challenge in developing workable quantum computers is the "leakage" of encoded information. This problem occurs when the hardware in a quantum computer encodes the information incorrectly in another state.

Because quantum states can easily become unstable because of outside disruptions, such as electrical noise, scientists need to isolate entangled quantum states from such disruptions.

This involves cooling the qubits nearly down to near absolute zero temperature using special-purpose refrigerators and maintaining them in a regulated, stable environment.

According to Microsoft, the new quantum computing system allows communication of information between qubits and the outside world while also maintaining the stability of the qubits. It claims it also allows scaled-up support for thousands of qubits, a leap ahead from previous technology.

The Gooseberry chips operates at 100 milliKelvin (mK) and dissipate very small amounts of heat, meaning a standard commercially-available research refrigerator can be used.

The cryo-compute core operates at about 2 K, which can be reached by immersion in liquid helium.

The findings of the research are detailed in a paper entitled A Cryogenic Interface for Controlling Many Qubits published this month in Nature.

Quantum computing research continues to advance apace. The latest breakthrough from Microsoft comes weeks after a team of scientists from Fermi National Accelerator Laboratory and five other institutions claimed that they achieved a sustained, long-distance 'quantum teleportation' with fidelity (data accuracy) greater than 90 per cent.

The scientists said that they were able to teleport qubits made of photons over a distance of 44 km (27 miles) over a fibre-optic network.

Earlier, in September 2020, an international research team led by scientists at University of Bristol said that they had developed a prototype city-wide quantum network, which could be used to send completely secure and unhackable messages over the internet.