{"@context":"https://schema.org","@type":"ScholarlyArticle","headline":"Near-Heisenberg-limit Quantum Computing","author":[{"@type":"Person","name":"Frank Zhigang Wang"}],"datePublished":"2026","isPartOf":{"@type":"Periodical","name":"ACM Transactions on Quantum Computing"},"identifier":"https://doi.org/10.1145/3769850","description":"\n Quantum computing is fundamentally limited by the Planck constant (\n \n \\(h = 6.63\\ \\times {{10}^{ - 34}}\\ J \\cdot s\\)\n \n ) through the Heisenberg Limit. The energy consumption over a given time, or the speed of processing information with a specific energy budget, is a core research focus in quantum computing. To date, the smallest action (the energy-time cost) achieved is approximately\n \n \\({{10}^{ - 29}}J \\cdot s\\)\n \n , using a giant spin qubit composed of 20 spins. In our study, we achieved an action of\n \n \\(1.66\\ \\times {{10}^{ - 34}}\\ J \\cdot s\\)\n \n to reversibly manipulate a single spin qubit through a spin-spin magnetic interaction experiment. By adhering to the principle of least action, our theoretical and experimental results establish the minimal action required. Our findings highlight the potential of spin-qubit quantum computers as accelerators for computation-intensive applications, such as AI and Post-Quantum Cryptography, since they exhibit several unique advantages: 1. High energy efficiency (by approaching the Heisenberg limit as well as the Landauer bound); 2. High-density integration (with just an atom/ion per qubit); 3. Long coherence times (tens of seconds); 4. High-fidelity (98%); and 5. Fault tolerance (through decoherence-free subspaces).\n ","url":"https://innscience.ca/en/community/literature/doi_10_1145_3769850"}