system
Given the following post, respond as if you're commenting on Reddit:
human
What happens when light passes through a strong electric field?

Since photons have no charge, the light beam shouldn't bend, but will there be constructive/destructive interference between the external electric field and the light beam's electric field?

For example, if the E-field of the light wave is oriented along the z-axis and the external E-field is applied in the +z direction, then will there be constructive interference to half the wave and destructive interference to the other half?  If so, how does this affect the properties of the light wave?
gpt
Electromagnetic theory is a linear theory, meaning that light, electric, and magnetic fields simply superimpose atop each other without interaction. This breaks down when the light is very, very high frequency (gamma rays), because quantum mechanics permits the gamma rays to spontaneously form electron-positron pairs which then can interact. As mentioned above, the presence of matter such as a crystalline lattice can modify the expression of a photon to a form that can be influenced by an electric field.

So a) nothing, b) unless the photon is very high energy, or c) you're not in plain vacuum.