New Error-Correction System Could Transform Qubit Efficiency

Scientists have designed error-correcting ‘logical qubits’ that could pave the way for scalable quantum computers with just a few hundred qubits.

Researchers at Nord Quantique, a quantum computing startup, have achieved a major breakthrough by developing individual physical qubits capable of error correction, resembling logical qubits. This advancement holds promise for quantum computers that surpass the capabilities of today’s most powerful classical supercomputers.

Traditional bits in classical computing represent data as either 1 or 0. In contrast, quantum bits (qubits) leverage quantum mechanics to encode data in a superposition of both states simultaneously, a phenomenon known as coherence. Quantum computers exploit entanglement, enabling parallel processing that classical computers cannot match.

However, qubits are prone to environmental interference, leading to high error rates. Achieving quantum supremacy typically requires millions of qubits, yet current quantum computers only have around 1,000 qubits. To address this challenge, researchers are exploring methods to reduce error rates, including building logical qubits composed of entangled qubits.

Nord Quantique’s approach involves designing individual physical qubits and applying bosonic codes during operation to mitigate errors at the qubit level. These codes leverage the quantum properties of bosons, such as photons, to protect against errors like bit-flips and phase-flips. In a study published in Physical Review Letters, Nord Quantique’s scientists demonstrated a 14% improvement in qubit coherence time, a significant achievement in error correction.

Their innovative method could enable quantum advantage with just hundreds of qubits, compared to previous estimates requiring millions of qubits. Julien Camirand Lemyre, Nord Quantique’s chief technology officer, emphasized that their approach integrates error correction directly into the physical qubits, effectively making them behave like logical qubits without the need for extensive redundancy.

While other companies pursue different error-reduction strategies, most rely on logical qubits. Nord Quantique’s approach stands out by embedding error correction into the hardware of each physical qubit using bosonic codes. Lemyre highlighted the efficiency of their approach compared to brute-force methods.

Nord Quantique aims to build a system with multiple error-correcting physical qubits by the Fall of this year. They plan to introduce a quantum computer featuring around 100 of these advanced qubits by 2028, potentially revolutionizing the computing landscape. This development could bring quantum computing closer to achieving quantum supremacy over classical computing.