A quantum method reaches the ultimate limit of precision even when the machine controlling it is relatively slow.
Learning the internal math of a quantum system usually requires incredibly fast control at ultra-short time intervals. This demonstration shows that the Heisenberg limit of precision can be achieved without those technical shortcuts. It bypasses a major hardware bottleneck that has plagued the field of quantum characterization for years. Researchers can now get perfect readings of a system using the slower hardware we already have. This jump in efficiency means we can build more stable quantum computers without waiting for better control electronics.
Heisenberg-limited Hamiltonian learning without short-time control
arXiv · 2604.27838
Characterizing quantum systems by learning their underlying Hamiltonians is a central task in quantum information science. While recent algorithmic advances have achieved near-optimal efficiency in this task, they critically rely on accessing arbitrarily short-time dynamics. This reliance poses severe experimental challenges due to finite control bandwidth and transient pulse errors. In this work, we demonstrate that Heisenberg-limited Hamiltonian learning can be achieved without short-time cont