标题： 在非同步量子时钟下测量量子粒子速度而不进行往返 显示英文标题

标题： Measuring the speed of quantum particles without a round-trip under non-synchronized quantum clocks

摘要： 测量光从一个空间位置传播到另一个空间位置（即单向光速）的速度时，主要问题之一是属于每个分离的空间位置的时钟无法且原则上不能以足够的精度进行同步。 这一问题是迄今为止所有光速测量都测量双向光速（即测量光从源点传播到另一位置再返回源点的速度）的主要原因，因此只需要一个时钟来测量速度。 在这里，我们表明，在原则上，通过采用量子力学描述，并结合两个边界条件以及两态矢量形式主义，同时假设非同步的量子时钟具有未知的时间膨胀，可以测量以光速运动的粒子的速度，而无需假设往返行程。 我们展示了对于拥有与量子粒子时钟不同步的时钟的测试粒子，其速度的弱值是可以测量的。 按照所提出的设置，即使不知道系统的时态，只要知道速度的弱值，这种弱速度就是双向光速。 否则，必须对量子时钟的时态作出假设，这将导致弱速度可能比双向光速慢甚至更快。 我们进一步探讨了该设置的一些基本含义。 所提出的方法为测量量子粒子的速度开辟了一条新途径，同时克服了关于时钟同步的相对论问题。 显示英文摘要

摘要： One of the main issues in measuring the speed of light when it only travels from one spatial position into another position, known as the one-way speed of light, is that the clocks belonging to each separated spatial position are not and, in principle, cannot be synchronized with sufficient precision. This issue is the main reason why all of the measurements of the speed of light until now have measured the two-way speed of light, i.e., measuring the speed of light that travels from a source to another location and back to the source, and so there is a need for only one clock to measure the speed. Here, we show that it is possible, in principle, to measure the velocity of particles that travel at the speed of light without assuming a round-trip once we adopt a quantum mechanical description under two boundary conditions to the state of the quantum system followed by the two-state-vector formalism while assuming non-synchronized quantum clocks with unknown time dilation. We show that the weak value of velocity can be measured for a test particle that has a clock that is not synchronized with the clock of the quantum particle. Following the proposed setup, when the weak value of the velocity is known even without knowing the time states of the system, such a weak velocity is the two-way speed of light. Otherwise, one has to impose assumptions regarding the time states of the quantum clocks, which then give weak velocities that can be slower or even faster than the two-way speed of light. We further explore some fundamental implications of the setup. The proposed approach opens a new avenue toward measuring the velocities of quantum particles while overcoming relativistic issues regarding the synchronization of clocks.