Arévalo Aguilar L M
Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, 18 Sur y Avenida San Claudio, Col. San Manuel, C.P. 72520, Puebla, PUE, Mexico.
Sci Rep. 2021 Mar 24;11(1):6744. doi: 10.1038/s41598-021-85508-8.
In 1927, at the Solvay conference, Einstein posed a thought experiment with the primary intention of showing the incompleteness of quantum mechanics; to prove it, he employed the instantaneous nonlocal effects caused by the collapse of the wavefunction of a single particle-the spooky action at a distance-, when a measurement is done. This historical event preceded the well-know Einstein-Podolsk-Rosen criticism over the incompleteness of quantum mechanics. Here, by using the Stern-Gerlach experiment, we demonstrate how the instantaneous nonlocal feature of the collapse of the wavefunction together with the single-particle entanglement can be used to produce the nonlocal effect of steering, i.e. the single-particle steering. In the steering process Bob gets a quantum state depending on which observable Alice decides to measure. To accomplish this, we fully exploit the spreading (over large distances) of the entangled wavefunction of the single-particle. In particular, we demonstrate that the nonlocality of the single-particle entangled state allows the particle to "know" about the kind of detector Alice is using to steer Bob's state. Therefore, notwithstanding strong counterarguments, we prove that the single-particle entanglement gives rise to truly nonlocal effects at two faraway places. This opens the possibility of using the single-particle entanglement for implementing truly nonlocal task.
1927年，在索尔维会议上，爱因斯坦提出了一个思想实验，其主要目的是表明量子力学的不完备性；为了证明这一点，他利用了在进行测量时单个粒子波函数坍缩所引起的瞬时非局域效应——即幽灵般的超距作用。这一历史事件早于著名的爱因斯坦 - 波多尔斯基 - 罗森对量子力学不完备性的批评。在此，通过使用斯特恩 - 盖拉赫实验，我们展示了波函数坍缩的瞬时非局域特征以及单粒子纠缠如何能够用于产生引导的非局域效应，即单粒子引导。在引导过程中，鲍勃得到的量子态取决于爱丽丝决定测量哪个可观测量。为了实现这一点，我们充分利用了单粒子纠缠波函数在大距离上的扩展。特别地，我们证明了单粒子纠缠态的非局域性使得粒子能够“知晓”爱丽丝用于引导鲍勃态的探测器类型。因此，尽管存在强烈的反对观点，我们证明了单粒子纠缠在两个遥远位置产生了真正的非局域效应。这开辟了利用单粒子纠缠来实现真正非局域任务的可能性。
