Mainstream optics
Refractive Index
A measure of how much the speed of light is reduced inside a medium. Light slows down in water, glass, and air compared to a vacuum.
Scientists / Papers
General physics principles
Theories Citing This Reference (2)
Negative Time as Refractive Index Engineering
The phenomenon of 'negative time' observed in laser-atom experiments is not time travel but the result of altering the medium's refractive index and permittivity via resonance, allowing light to effectively travel faster than c locally.
Warp Drive via Medium Manipulation
Warp drives are possible by manipulating the refractive index of the vacuum/ether, allowing particles (or ships) to travel faster than light relative to the medium without violating causality in the same way as vacuum light speed limits.