Chinese researchers have demonstrated a silicon quantum processor capable of performing a full set of error-detecting logical operations, marking a key step toward practical quantum computing.
The team from Shenzhen International Quantum Academy built a device that can process quantum information while checking for errors, something previously shown in platforms like superconducting circuits but not in silicon.
Quantum systems are highly sensitive to noise, which introduces errors that can disrupt calculations. One solution is to encode information into logical qubits that can detect and handle such errors.
The researchers say their work shows that the essential building blocks for fault-tolerant quantum computing are now achievable in silicon, a material widely used in modern electronics.
From qubits to logic
The processor was created by placing phosphorus atoms into silicon with atomic precision, allowing individual control of quantum bits. The team also developed methods to reduce signal interference, a major source of error in quantum systems.
Using four qubits, the researchers encoded two logical qubits capable of detecting errors during computation. This approach allowed the system to flag unwanted noise that could otherwise affect results.
The study demonstrated a complete chain of operations, including preparing error-checked states, performing logical operations, and applying them in an algorithm.
To test the system, the team ran a quantum algorithm to calculate the lowest-energy state of a water molecule. The result closely matched the theoretical value, showing the system can handle practical tasks.
Running real algorithms now
The researchers used the Variational Quantum Eigensolver to simulate the molecule, achieving results with small deviation from expected values. This indicates the approach could support real-world quantum applications in the future.
The work also showed that silicon-based systems can move beyond controlling small numbers of qubits to performing coordinated operations with built-in error detection.
Silicon remains a strong candidate for scaling quantum computers because it is already widely used in semiconductor manufacturing, which could help future systems be produced more efficiently.
The team said the next steps include improving precision in atom placement, reducing interference further, and increasing the number of qubits on a single chip.
The longer-term goal is to build larger systems that can perform more complex computations while maintaining error control.
The study was published in Nature Nanotechnology.