The Bose-Marletto-Vedral (BMV) experiment tests a quantum gravitational effect predicted by low energy perturbative quantum gravity. It has received attention because it may soon be within observational reach in the lab. We point out that: (i) in relativistic language, the experiment tests an interference effect between proper-time intervals; (ii) the feasibility study by Bose et al. suggests that current technology could allow to probe differences of such proper-time intervals of the order of 10⁻³⁸ seconds, about twenty orders of magnitude beyond the current resolution of the best atomic clocks; (iii) the difference of proper times approaches Planck time (10⁻⁴⁴ s) if the masses of the particles in the experiment approach the Planck mass (~micrograms). This implies that the experiment might open a window on the structure of time at the Planck scale. We show that if time differences are discrete at the Planck scale—as research in quantum gravity may suggest—the Planckian discreteness of time would appear as quantum levels of an in principle measurable entanglement entropy.

Bose-Marletto-Vedral（BMV）实验测试了由低能微扰量子引力预测的量子引力效应。它已受到关注，因为它可能很快就会在实验室中达到观察范围。我们指出：（i）以相对论语言，该实验测试了适当时间间隔之间的干扰效果；（ii）Bose等人的可行性研究。这表明当前的技术可以允许探测这种大约10到³⁸秒的适当时间间隔的差异，这比最佳原子钟的当前分辨率超出了大约二十个数量级；（iii）适当时间的差异接近普朗克时间（10 ^-44s）如果实验中的粒子质量接近普朗克质量（〜微克）。这意味着实验可能会在普朗克尺度上打开时间结构的窗口。我们证明，如果时间差在普朗克尺度上是离散的（如量子引力的研究可能暗示的那样），则普朗克时间的离散性将作为原则上可测量的纠缠熵的量子能级出现。