Integrated quantum computing company Quantinuum Ltd. and Microsoft today announced a breakthrough in bringing higher reliability to quantum error correction, which will advance the path toward building hybrid quantum supercomputing systems.

Researchers applied Microsoft’s qubit-virtualization system, which uses error diagnostics and correction, to Quantinuum’s ion-trap hardware, successfully demonstrating error rates 800 times lower than physical systems alone. Using the new system, the team was able to run more than 14,000 individual experiments without a single error.

Quantum computing uses qubits to store and process information. Unlike a classical bit that is a 1 or a 0, a qubit can also exist in a superposition where its state is indeterminate — has a probability of being a 1 or a 0 — or entangled with another qubit. Because of the hardware that qubits are built on, which is often sensitive superconducting circuitry to resolve the measurements, qubits can be extremely error-prone.

Quantinuum combined its 32-qubit H2 quantum processor, powered by Honeywell International Inc., with Microsoft’s new error correction system. This led to what both companies said generated the most “reliable logical qubits,” by creating four logical qubits using 30 of the 32 physical qubits available on the H2.

The team also diagnosed and corrected errors in logical qubits without destroying them – a practice known as “active syndrome extraction.” This breakthrough is particularly important because it represents an important milestone toward reliable quantum computation.

Microsoft likened its qubit error correction system to using a high-quality noise-canceling headset to increase the clarity of sound in a noisy environment. It corresponds to an approximately 29-decibel improvement in signal, according to the joint team, which in terms of headphones would knock out even fairly loud annoying noises such as a vacuum cleaner or a busy street.

“With our qubit-virtualization system, we were able to create four highly reliable logical qubits from only 30 physical qubits of the available 32 on Quantinuum’s machine,” the team said in its announcement. “When entangled, these logical qubits exhibited a circuit error rate of 10⁻⁵ or 0.00001, which means they would experience an error only once in every 100,000 runs. That is an 800x improvement over the circuit error rate of 8×10⁻³ or 0.008, measured from entangled physical qubits.”

This achievement will help lead to a new era in computing called “Level 2 Resilient,” where quantum supercomputers are capable of dealing with the issues caused by errors and can tackle meaningful challenges such as modeling states of molecules and materials, simulate complex systems in condensed matter physics, and explore new branches of science. This includes scientific disciplines that are currently beyond the scale of conventional computing, such as large-scale climate simulation, astronomical simulations, drug discovery and advanced material sciences.

“Quantum error correction often seems very theoretical,” said Dr. David Shaw, chief analyst at Global Quantum Intelligence. “What’s striking here is the massive contribution Microsoft’s midstack software for qubit optimization is making to the improved step-down in error rates. Microsoft really is putting theory into practice.”

Microsoft said advanced capabilities based on this new technology will be available in private preview for Azure Quantum Elements, the company’s purpose-built infrastructure for research and development productivity, in the coming months.

Photo: Quantinuum