Tilman SauerTilman Sauer is an historian of physics specializing in general relativity, the foundations of physics, and the philosophy of quantum mechanics. He was a contributing editor for volumes 3 and 4 of the Collected Papers of Albert Einstein. While carefully reading through some 1800 pages of Einstein's manuscripts that were shipped from Princeton to the Albert Einstein Archives in Jerusalem, Sauer found a few short lines about the Einstein-Podolsky-Rosen paradox that considered the result of a measurement of a two-valued spin component and the "knowledge at a distance" that comes into existence instantly for widely separate entangled particles. Einstein was clearly responding to the 1952 suggestion of David Bohm that EPR measurements could be carried our more easily on the discrete values of electron spin than the continuous values of position and momentum in the original EPR paper. Bohm was hoping that such measurements could reveal the existence of "hidden variables."
Composite system of total spin 0.Sauer says the following lines were written at the right margin of the page:
a) the description by the quantum theory is an incomplete one with respect to the individual system, orThis last line is what Erwin Schrödinger had told Einstein would be the case back in 1935, calling the particles "entangled." While Einstein called this "action-at-a-distance" in 1935 (even for a single particle relative to its wave in 1927), and more dramatically called it "spooky action-at-a-distance" in 1948, we now know it is just "knowledge-at-a-distance." Neither particle "acts" on the other. They acquire their values simultaneously to conserve the total spin.
Reference''An Einstein manuscript on the EPR paradox for spin observables.'' Studies in History and Philosophy of Modern Physics 38 (2007) 879-887; [philsci-archive.pitt.edu/archive/00003222] Normal | Teacher | Scholar