标题： 使用薛定谔猫态的量子增强暗物质探测 显示英文标题

标题： Quantum-enhanced dark matter detection using Schrödinger cat states

摘要： 量子计量学使得暗物质检测变得敏感，特别是使用非经典态，如包含微波腔中亚普朗克干涉结构的薛定谔猫态。 在此，我们报告了四组分薛定谔猫态在高质量超导微波腔中的首次实验应用，用于探测暗光子，这是一种潜在的暗物质候选者。 我们展示了信号光子速率提高了8.1倍，并将暗光子的动能混合角限制到前所未有的$\epsilon < 7.32 \times 10^{-16}$，接近6.44~GHz (26.6~$\mu$eV)。 通过采用参数边带驱动主动调节腔体频率，我们在多个频率区间内实现了暗光子搜索和背景减除，从而在100~kHz带宽内达到$10^{-16}$水平的灵敏度。 我们的薛定谔猫辅助探测（SCaD）方案相比之前的结果有显著改进，有望在量子增强的新物理探索中产生重要影响。 显示英文摘要

摘要： Quantum metrology enables sensitive dark matter detection, particularly using nonclassical states, such as Schr\"odinger cat states featuring sub-Planck interference structures in microwave cavities. Here, we report the first experimental application of four-component Schr\"odinger cat states within a high-quality superconducting microwave cavity to detect dark photons, a potential dark matter candidate. We demonstrate an 8.1-fold enhancement in the signal photon rate and constrain the dark photon kinetic mixing angle to an unprecedented $\epsilon < 7.32 \times 10^{-16}$ near 6.44~GHz (26.6~$\mu$eV). By employing a parametric sideband drive to actively tune the cavity frequency, we achieve dark photon searches and background subtraction across multiple frequency bins, yielding a sensitivity at the $10^{-16}$ level within a 100~kHz bandwidth. Our Schr\"odinger's cat-assisted detection (SCaD) scheme demonstrates a substantial improvement over previous results, promising potential implications in quantum-enhanced searches for new physics.