Microsoft and Quantinuum achieved a considerable breakthrough in quantum computing by demonstrating the most reliable logical qubits on record. The result of the two firms' collaboration is a quantum computing system that reduces the error rate for data processing, moving the field beyond the current noisy intermediate-scale quantum (NISQ) era.

'Qubits' are the fundamental unit of computing in quantum systems. They can be in multiple states at the same time, which explains their potential to produce a tremendous increase in computing power.
Qubits are fast but highly sensitive to noise and prone to errors, causing data mistakes when the quantum computer is disturbed. To address this problem, quantum researchers frequently create more physical qubits than necessary and employ error-correction techniques to produce a lower number of functional and reliable qubits.

Using Quantinuum's H2 quantum computer, Microsoft built an error-correction algorithm for Quantinuum's physical qubits, resulting in around four functional logical qubits from 30 physical ones. Microsoft's qubit-virtualization system was applied to Quantinuum's ion-trap hardware, allowing the team to run more than 14,000 individual experiments without a single error, an improvement of up to 800 times better than previously with physical qubits.

Why does it matter?

The initiative is the latest in a race to develop quantum computing, with big tech giants such as Microsoft, Google, and IBM competing with challengers and even nations to build computers based on quantum physics. The promise is to reach much higher speeds than traditional silicon-based computers, so quantum-powered machines could perform computations that would take thousands of years with existing conventional computers.

The new approach enabled the team to perform error diagnostics and corrections on logical qubits without destroying them, a critical step for fault-tolerant quantum computing. The achievement marks a transition into the next phase of quantum computing, known as 'Level 2 Resilient', which is crucial for solving problems with reliable quantum computing. Microsoft and Quantinuum's results have the potential to greatly accelerate progress toward the supreme goal of tackling real-world situations and transforming fields such as materials science and quantum AI.

Quantum experts often mention 100 reliable qubits as the minimum number required to beat conventional supercomputers and crack problems, and 1000 to create a significant commercial advantage. Both companies plan to continue investing in progressing beyond Level 2, scaling to the level of quantum supercomputing.