  The entangled Schrodinger cat state obtained immediately upon measurement of
a superposed two-state quantum system is often considered paradoxical because
it appears to predict two macroscopically different outcomes, such as an alive
and dead cat. However, nonlocal interferometry experiments testing
momentum-entangled photon pairs over all phases demonstrate that the cat state
does not fit this description and is not paradoxical. Both experiment and
theory imply that it instead represents a superposition of two nonlocally
coherent (i.e. phase-dependent) statistical correlations between its
sub-systems. This is not paradoxical. Standard quantum theory rigorously
predicts the experimentally-observed outcomes of this state. Neither sub-system
is superposed; rather, the correlations between the states of the subsystems
are superposed. This resolves the problem of definite outcomes. The nonlocal
properties of entanglement then ensure that only one outcome occurs while the
other outcome simultaneously does not occur, resolving a problem posed by
Einstein in 1927. The single outcome that occurs then triggers an irreversible
process leading to macroscopic registration of the outcome. This resolves the
quantum measurement problem. Collapse occurs because of entanglement and does
not require a special collapse postulate. Collapse is a consequence of standard
quantum physics and the irreversible nature of the macroscopic registration.
