Albert Einstein Boris Podolsky Nathan Rosen Einstein–Podolsky–Rosen paradox thought experiment quantum-mechanical quantum state Erwin Schrödinger German correlation quantum mechanics particles EPR paradox
In 1935, Albert Einstein, Boris Podolsky and Nathan Rosen published a paper on the counterintuitive predictions that quantum mechanics makes for pairs of objects prepared together in a particular way. In this study, the three formulated the Einstein–Podolsky–Rosen paradox (EPR paradox), a thought experiment that attempted to show that "the quantum-mechanical description of physical reality given by wave functions is not complete." However, the three scientists did not coin the word entanglement, nor did they generalize the special properties of the quantum state they considered. Following the EPR paper, Erwin Schrödinger wrote a letter to Einstein in German in which he used the word Verschränkung (translated by himself as entanglement) "to describe the correlations between two particles that interact and then separate, as in the EPR experiment."
