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The geometrical approximation of the extended Maxwell equation in curved
spacetime incorporating interactions induced by the vacuum polarization
effects is considered. Taking into account these QED interactions and
employing the analogy between eikonal equation in geometrical optics and
Hamilton-Jacobi equation for the particle motion, we study the phase structure
of the modified theory. There is a complicated, local induced phase which is
believed to be responsible for the modification of the classical picture of
light ray. The main features of QGO could be obtained through the study of
this induced phase. We disscuss initial principles in conventional and
modified geometrical optics and compare the results.
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