标题： 关于冯·诺依曼投影测量指针态、弱值和干涉的一点说明 显示英文标题

标题： A Note Concerning von Neumann Projector Measurement Pointer States, Weak Values, and Interference

摘要： 众所周知，从对处于预选态 |{\psi }> 的量子系统系综进行的投影算符 A 的冯·诺伊曼测量中得到的指针态 |{\Phi }> 依赖于 A|{\psi }>。这里表明，从对也进行后选择的系综进行此类测量中得到的指针态 |{\Psi }> 依赖于 A 的弱值——无论测量相互作用强度如何。还发现，虽然 |{\Psi }> 的空间分布表现出干涉，但 A 的幂等性禁止了 |{\Phi }> 中的干涉。这是用哪条路径信息来解释的。 显示英文摘要

摘要： It is well known that the pointer state |{\Phi}> resulting from the von Neumann measurement of a projection operator A performed upon an ensemble of quantum systems in the preselected state |{\psi}> depends upon A|{\psi}>. Here it is shown that the pointer state |{\Psi}> obtained from such a measurement performed upon an ensemble that is also postselected depends upon the weak value of A - regardless of the measurement interaction strength. It is also found that, while the spatial distribution of |{\Psi}> exhibits interference, the idempotency of A prohibits interference in that of |{\Phi}>. This is explained in terms of welcher Weg information.