Restoring entanglement in atomic collisions: A gedanken experiment

Anton Zeilinger

Yu Shi

Abstract The famous gedanken experiments of quantum mechanics have played crucial roles in developing the Copenhagen interpretation. They are studied here from the perspective of standard quantum mechanics, with no ontological interpretation involved. Bohr's investigation of these gedanken experiments, based on the uncertainty relation with his interpretation, was the origin of the Copenhagen interpretation and is still widely adopted, but is shown to be not consistent with the quantum mechanical view. We point out that in most of these gedanken experiments, entanglement plays a crucial role, while its buildup does not change the uncertainty of the concerned quantity in the way thought by Bohr. Especially, in the gamma ray microscope and recoiling double‐slit gedanken experiments, we expose the entanglement based on momentum exchange. It is shown that even in such cases, the loss of interference is only due to the entanglement with other degrees of freedom, while the uncertainty relation argument, which has not been questioned up to now, is not right.

Hoshang Heydari

Padmanabhan Murali

Experimental realization of Gedanken experiments on Quantum Mechanics continue to suggest inferences of action at a distance, action into the future or past as reported in Delayed choice Quantum entanglement experiments recently by Ma et al (2012). Is it possible to read through this and investigate through simple logic and experiments whether control of the past or future is possible? A set of experiments are suggested here to do the same whose results may be interesting. Gedanken experiments on Quantum Mechanics principles Einstein, Podolsky and Rosen (Einstein et al, 1935) were the first to suggest a Gedanken experiment which would suggest instant communication over a distance between particles which was against the principle of Special

F. J. Duarte

F.J. Duarte