It is of great importance to determine an unknown quantum state for fundamental studies of quantum mechanics, yet it is still difficult to characterize systems of large dimensions in practice. Although the scan-free direct measurement approach based on a weak measurement scheme was proposed to measure a high-dimensional photonic state, how weak the interaction should be to give a correct estimation remains unclear. Here we propose and experimentally demonstrate a technique that measures a high-dimensional quantum state with the combination of scan-free measurement and direct strong measurement. The procedure involves sequential strong measurement, in which case no approximation is made similarly to the conventional direct weak measurement. We use this method to measure a transverse state of a photon with effective dimensionality of 65000 without the time-consumed scanning process. Furthermore, the high fidelity of the result and the simplicity of the experimental apparatu...

中文翻译：

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高强度量子态的直接强测量

对于量子力学的基础研究而言，确定未知的量子状态非常重要，但在实践中仍然难以表征大尺寸的系统。尽管提出了一种基于弱测量方案的免扫描直接测量方法来测量高维光子状态，但尚不清楚相互作用应有多弱才能给出正确的估计。在这里，我们提出并通过实验证明了一种结合无扫描测量和直接强测量来测量高维量子态的技术。该过程涉及顺序的强测量，在这种情况下，与常规的直接弱测量不同，不会进行近似计算。我们使用这种方法来测量有效尺寸为65000的光子的横向状态，而无需耗时的扫描过程。此外，结果的高保真度和实验仪器的简便性...