  The delayed-choice thought experiment proposed by Wheeler has been
demonstrated over the last several decades for the wave-particle duality of a
single photon. The delayed-choice quantum eraser proposed by Scully and Druhl
has also been intensively studied for the violation of the cause-effect
relation of a single photon as well as a pair of entangled photons in an
interferometric system. Here, a coherence interpretation is conducted for the
nonlocal realism of the space-like separated photons observed in Phys. Rev.
Lett. 84, 1 (2000). As a result, coherence solutions of the observed nonlocal
fringes are deterministically derived from coincidence detection-caused
selective measurements, where the resulting product-basis superposition becomes
the origin of the otherwise quantum mystery of the nonlocal fringes. For this,
a fixed sum-phase relation between entangled photons is a prerequisite, which
cannot be explained by conventional particle nature-based quantum mechanics.
