A research team at ETH Zurich has demonstrated a new approach to quantum computing that could ease one of the central barriers facing quantum systems: instability during calculations.
The team developed a quantum swap gate for neutral-atom qubits that maintained better than 99.9% precision across 17,000 qubit pairs simultaneously, according to research published in Nature. The concept uses a geometry-based technique that reduces sensitivity to fluctuations from laser systems, a longstanding challenge in neutral-atom quantum computing.
The development is particularly significant because quantum computers remain limited by error rates that are far higher than those in conventional computers. Traditional computers fail at rates approaching one in a trillion operations, while quantum systems encounter failures closer to one in a thousand operations. That gap is one of the factors that prevents quantum computing from attaining mainstream adoption.
The quantum computing industry continues to explore multiple hardware approaches simultaneously, including superconducting systems and photonic architectures. The ETH Zurich results strengthen the position of neutral atoms as one of the more scalable contenders in that race.
Swap Operations
Neutral-atom quantum systems have emerged as a promising architecture because they can potentially support thousands of qubits in a single platform. Unlike superconducting circuits or trapped ions, neutral atoms carry no electric charge, making them less vulnerable to external interference. But running these systems in the real world is difficult because many quantum gate operations need such extremely precise laser control.
The ETH Zurich researchers sought to reduce that dependence. Rather than relying primarily on effects tied to laser intensity and timing, the team used what physicists call a geometric phase. In this approach, the quantum operation depends mainly on the path atoms travel through an optical lattice, which is an artificial crystal formed by intersecting laser beams.
The experiment used ultracold potassium atoms trapped in this artificial crystal. By bringing pairs of atoms close enough for their quantum wave functions to overlap, the researchers created swap operations that exchanged the quantum states of neighboring qubits.
The result: The swap gates completed their operations in less than a millisecond while maintaining 99.91% precision across all 17,000 qubit pairs.
The ETH Zurich team also demonstrated half-swap operations, which partially exchange quantum information while generating entanglement between qubits. Entanglement is essential for practical quantum algorithms because it enables correlations between qubits that do not exist in conventional computing.
Researchers see these half-swap operations as a necessary component for future fault-tolerant quantum systems.
Major Advances Still Required
The research, while promising, does not mean practical quantum computers are imminent. Researchers acknowledged that major advances are still required in both system scale and operational reliability before quantum systems can tackle enterprise workloads.
Still, the findings indicate that neutral-atom systems may require fewer qubits than previously believed to solve advanced computational problems. For instance, some researchers now estimate that Shor’s algorithm, commonly associated with breaking modern encryption systems, could potentially operate with roughly 10,000 qubits instead of millions.
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Originally published by Techstrong.IT. Republished with attribution.
