Nonentangling channels for multiple collisions of quantum wave packets
Nonentangling channels for multiple collisions of quantum wave packets
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量子波包多次碰撞的非纠缠通道
DOI：
10.1103/physreva.85.032713
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发表时间：
2011
影响因子：
2.9
通讯作者：
B. Fine
中科院分区：
文献类型：
--
作者：
W. Hahn;B. Fine
我们考虑一维量子波包的多重碰撞。被研究的系统由一个不可穿透的壁和两个质量非常不同的硬核粒子组成。较轻的粒子在较重的粒子和壁之间反弹。这两种粒子最初都由窄高斯波包表示。基于一种新的方法，给出了该问题的完整解析解。该方法的思想是将两粒子波函数分解成一个连续的叠加项（通道），使得每个通道内的多次碰撞不会导致两个粒子之间的后续纠缠。对于每个通道，两粒子波函数的时间演化完全由相应的经典点状粒子的运动决定;因此整个量子问题被简化为经典计算。基于上述方法的计算揭示了以下意想不到的结果：由于碰撞，两个粒子之间的纠缠首先随着时间的推移而增加，但随后它开始减少，当轻粒子变得太慢而无法赶上重粒子时完全消失。
We consider multiple collisions of quantum wave packets in one dimension. The system under investigation consists of an impenetrable wall and of two hard-core particles with very different masses. The lighter particle bounces between the heavier one and the wall. Both particles are initially represented by narrow Gaussian wave packets. A complete analytical solution of this problem is presented on the basis of a new method. The idea of the method is to decompose the two-particle wave function into a continuous superposition of terms (channels), such that the multiple collisions within each channel do not lead to subsequent entanglement between the two particles. For each channel, the time evolution of the two-particle wave function is completely determined by the motion of the corresponding classical point-like particles; therefore the whole quantum problem is reduced to a classical calculation. The calculation based on the above method reveals the following unexpected result: The entanglement between the two particles first increases with time due to the collisions, but then it begins to decrease, disappearing completely when the light particle becomes too slow to catch up with the heavy one.