Nonlocality arises if and only if we assume that the measurement of the spin of a particle "collapses the
wave function" from the linear superposition to
either j ">1 j #>2 or j #>1 j ">2 in (1). If such a collapse
occurs, then measuring the spin of particle one would fix the spin of particle two. The spin of particle two
would be fixed instantaneously, even if the particles had been allowed to separate to large distances. If at the
location of particle one, we make a last minute decision to measure the spin of particle one in the left-right
direction rather than the up-down direction, then instantaneously the spin of particle two would be fixed in
the opposite direction as particle one --
if we assume that (2) collapses at the instant we measure the spin
of particle one. The mystery of quantum nonlocality lies in trying to understand how particle two changes
-- instantaneously-- in response to what has happened in the location of particle one.
There is no mystery. There is no quantum nonlocality. Particle two
doesn't know what has happened
to particle one when its spin is measured. State transitions are nice and local in quantum mechanics.
These statements are true because quantum mechanics tells us that the wave function does
not collapse
when the state of a system is measured. In particular, nonlocality disappears when the Many-Worlds
Interpretation (MWI) [6,7,8,16] is adopted. The MWI dispels the mysteries of quantum mechanics.