China team builds first silicon chip with elements for fault-tolerant quantum computing

Quantum computers are designed to solve certain problems that would overwhelm even the fastest conventional computers.

Image: Shutterstock Chinese researchers have shown that a silicon quantum chip can carry out a full set of error-detecting logical operations – the first time this has been done and a key step towards building reliable quantum computers.

The study, published in Nature Nanotechnology on Monday, found the device could process quantum information with built-in error checks – something previously achieved in platforms like superconducting circuits but not with silicon.

According to the team from the Shenzhen International Quantum Academy, the study showed that the core building blocks needed for a broadly useful error-tolerant quantum computer were “now in place in silicon” – a material used in smartphones, laptops and data centres.

The researchers also used the processor to calculate the lowest-energy state of a water molecule, producing a result close to the theoretical value.

They said this showed the approach was “feasible for running practical quantum algorithms”.

Quantum computers are designed to solve certain problems that would overwhelm even the fastest conventional computers, such as simulating molecules or optimising complex systems.

Unlike ordinary computers, which process information as 0s and 1s, quantum computers use quantum bits – or qubits – which can represent multiple possibilities at once and make some calculations far more efficiently.

So far, scientists have built prototype quantum computers using materials such as superconducting circuits, trapped ions and neutral atoms.

For instance, Google is a major player in superconducting quantum computing, while in China a photonic system called Jiuzhang has drawn global attention.

As the foundation of the modern chip industry, silicon is attractive because quantum machines built on it could one day be made more easily and at a larger scale.

Before this study, silicon quantum devices had shown high-precision control over small numbers of qubits, but getting them to work together in a way that could check for errors had remained a major challenge.

The Shenzhen team built the processor for the study by placing phosphorus atoms into silicon with atomic precision, creating a tiny device in which the quantum bits could be individually controlled.

They also developed a way to reduce signal interference – a major source of error in quantum systems.

Using four of those quant

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