论文标题
两种挤压状态
Bipartite temporal Bell inequalities for two-mode squeezed states
论文作者
论文摘要
两分的时间钟性不平等与通常的铃铛不等式相似，除非，除了在每次测量时更改极化者的方向，而是改变了进行测量的时间。通过这样做，人们能够测试现实主义和地方，但仅依靠位置测量。这在无法探测动量方向的实验设置中特别有用（例如，在宇宙学中）。我们研究了放置在两种模式挤压状态下的连续系统的这些两分钟的时间铃不平等，并在参数空间中找到了一些区域，在这些区域确实违反了它们。我们强调了旋转角的作用，旋转角是表征两种挤压状态的三个参数之一（其他两个是挤压振幅和挤压角）。在单时间测量中，它仅确定波函数的整体阶段，因此可以被丢弃，但是在多次测量中，其时间动力学变得相关，并至关重要地确定何时违反了两部分时间钟形不平等。我们的研究为观察贝尔不平等现象的新实验设计开辟了可能性。
Bipartite temporal Bell inequalities are similar to the usual Bell inequalities except that, instead of changing the direction of the polariser at each measurement, one changes the time at which the measurement is being performed. By doing so, one is able to test for realism and locality, but relying on position measurements only. This is particularly useful in experimental setups where the momentum direction cannot be probed (such as in cosmology for instance). We study these bipartite temporal Bell inequalities for continuous systems placed in two-mode squeezed states, and find some regions in parameter space where they are indeed violated. We highlight the role played by the rotation angle, which is one of the three parameters characterising a two-mode squeezed state (the other two being the squeezing amplitude and the squeezing angle). In single-time measurements, it only determines the overall phase of the wavefunction and can therefore be discarded, but in multiple-time measurements, its time dynamics becomes relevant and crucially determines when bipartite temporal Bell inequalities can be violated. Our study opens up the possibility of new experimental designs for the observation of Bell inequality violations.
