The Einstein-Podolsky‒Rosen paradox is resolved in the way which Einstein would have liked least

—Template:Bell66a

EPR

Einstein-Podolsky-Rosen correlations or EPR for short, embed the essence of quantum mechanics mysteries.

Genesis of EPR

The birth of the EPR paradox is best described in Ref.  where it is apparently Rosen who, from his own work with entanglement in the Hyrogen atom, commented to Einstein difficulties in interpretations, who immediately understood this was in his favor in the Bohr-Einstein debates. Podolsky joined the discussion and proposed to write a paper, which he (Podolsky) did and later passed to the New York Times ahead of publication, with the result of infuriating Einstein who, Peres says, would no longer speak to him.

Podolsky, in fact, penned the EPR paper, which quickly became a centerpiece in the debate over the interpretation of quantum theory, a debate that continues today. Einstein wasn’t thrilled with the approach taken by Podolsky, who submitted the paper to Physical Review on March 25. In a letter dated June 19, 1935, to Erwin Schrödinger, Einstein wrote, “For reasons of language this [paper] was written by Podolsky after several discussions. Still, it did not come out as well as I had originally wanted; rather, the essential thing was, so to speak, smothered by the formalism [gelehrsamkeit].”

Podolsky went on to commit a grave blunder, in Einstein’s view, when he leaked the advance report of the EPR findings published by the New York Times. The newspaper subsequently printed a statement by Einstein, in which he stated that the information “was given to you without my authority. It is my invariable practice to discuss scientific matters only in the appropriate forum and I deprecate advance publi­cation of any announcement in regard to such matters in the secular press.” According to Peres, Einstein was so upset by Podolsky’s indiscretion that he never spoke with him again.

—Kelly Devine Thomas in Ref.

A clean version of the said New-York Times article is difficult to find although snapshots can be, for instance from this collectible which has good high-resolution extracts but not of the full text, or on the opposite,full-text versions tough to decipher at places though:

The content is not inaccurate, although this provides an early example of a frustrating experience with media coverage.

Bell's inequalities

Such correlations are challenged by Bell's inequalities.

The Bell inequalities can be recast in the so-called CHSH inequality form.

GHZ

Links

• Sciencenews.org
• EPR on Wolfram Alpha.
• Nice report from a conference with a photo of GHZ together.

References

• Proposed Experiment to Test Local Hidden-Variable Theories. J. F. Clauser, M. A. Horne, A. Shimony and R. A. Holt in Phys. Rev. Lett. 23:880 (1969).