论文标题
实施投影测量需要多长时间？
How long does it take to implement a projective measurement?
论文作者
论文摘要
根据Schrödinger方程，封闭的量子系统会及时不断发展。但是，如果要经过测量，则其状态随机和不连续变化，这是由投影假设描述的。但是，这种不连续的变化需要多长时间？基于简单的估计，其有效性仅取决于自然界中所有基本力都是有限的事实，我们表明量子测量的实施需要最短的时间。这段时间与量子机械对象的直径成比例地缩放，该对象的直径在其上可观察到的非通知作用，比例常数约为$ 10^{ - 5} $ s/m。通过与实验报告的不同平台的测量时间进行比较，我们确认了我们的约束。我们对我们的论点进行了教学阐述，沿着现代概念（例如基于Ancilla的测量，量子速度限制和Lieb-Robinson速度界限）介绍。
According to the Schrödinger equation, a closed quantum system evolves continuously in time. If it is subject to a measurement however, its state changes randomly and discontinuously, which is mathematically described by the projection postulate. But how long does it take for this discontinuous change to occur? Based on simple estimates, whose validity rests solely on the fact that all fundamental forces in nature are finite-ranged, we show that the implementation of a quantum measurement requires a minimum time. This time scales proportionally with the diameter of the quantum mechanical object, on which the measured observable acts non-trivially, with the proportionality constant being around $10^{-5}$ s/m. We confirm our bound by comparison with experimentally reported measurement times for different platforms. We give a pedagogical exposition of our argumentation introducing along the way modern concepts such as ancilla-based measurements, the quantum speed limit, and Lieb-Robinson velocity bounds.
