摘要
We report a scheme for quantum sensing in ultracold atoms by utilizing an atom-interferometer producing sub-Planck scale structures. The condensate is trapped in a hybrid potential, comprising of an overall harmonic trap and sharp potential barriers which are designed as 50-50 atomic beam-splitters. A scaling law for quantum sensing is established for ultracold atoms and the maximum limit of quantum sensing is identified. Quantum sensing for position, momentum and temperature are demonstrated with a sufficiently stable condensate. The present scheme reveals maximum limit of quantum sensitivity for ultracold atoms against infinitesimal external perturbations. With a designable time sequence for the trapping potential, our results provide a promising scheme for quantum sensing with Bose-Einstein condensate in atomic chips.