  The entangled "measurement state" (MS), predicted by von Neumann to arise
during quantum measurement, seems to display paradoxical properties such as
multiple macroscopic outcomes. But analysis of interferometry experiments using
entangled photon pairs shows that entangled states differ surprisingly from
simple superposition states. Based on standard quantum theory, this paper shows
that (i) the MS does not represent multiple detector readings but instead
represents nonparadoxical multiple statistical correlations between system
states and detector readings, (ii) exactly one outcome actually occurs, and
(iii) when one outcome occurs, the other possible outcomes simultaneously
collapse nonlocally. Point (iii) resolves an issue first raised in 1927 by
Einstein who demonstrated that quantum theory requires instantaneous state
collapse. This conundrum's resolution requires nonlocal correlations, which
from today's perspective implies the MS must be an entangled state. Thus,
contrary to previous presumed proofs of the measurement problem's insolubility,
we find the MS to be the collapsed state and just what we expect upon
measurement.
