论文标题
时间旅行台球球时钟：量子模型
Time-travelling billiard-ball clocks: a quantum model
论文作者
论文摘要
一般相对性预测了封闭的时机曲线（CTC）的存在，物体可以沿着它自己的过去传播。 CTC的结果是确定论的失败，即使对于经典系统：一种初始条件可能会导致多种演变。在这里，我们介绍了一个新的量子公式的典型示例，台球球可以沿着两个可能的轨迹传播：一个不受干扰的轨迹，一个沿着CTC沿着CTC与过去的自我相撞。我们的模型包括真空状态，使球在每个轨迹上存在或不存在，而时钟则提供了一种可区分轨迹的操作方法。我们将CTC的两个最重要的量子理论应用于我们的模型：Deutsch的模型（D-CTC）和后选择的传送（P-CTC）。我们发现D-CTC以混合状态的形式重现了经典解的多样性，而P-CTC则预测了这两个轨迹的同等叠加，从而支持Friedman等人的猜想。 [物理。 Rev. D 42，1915（1990）]。
General relativity predicts the existence of closed timelike curves (CTCs), along which an object could travel to its own past. A consequence of CTCs is the failure of determinism, even for classical systems: one initial condition can result in multiple evolutions. Here we introduce a new quantum formulation of a classic example, where a billiard ball can travel along two possible trajectories: one unperturbed and one, along a CTC, where it collides with its past self. Our model includes a vacuum state, allowing the ball to be present or absent on each trajectory, and a clock, which provides an operational way to distinguish the trajectories. We apply the two foremost quantum theories of CTCs to our model: Deutsch's model (D-CTCs) and postselected teleportation (P-CTCs). We find that D-CTCs reproduce the classical solution multiplicity in the form of a mixed state, while P-CTCs predict an equal superposition of the two trajectories, supporting a conjecture by Friedman et al. [Phys. Rev. D 42, 1915 (1990)].
