FLASH! RELATIVISTS PANIC AS SPEED OF LIGHT DROPS TO ZERO!February 7, 2018
I knew that Onion-like headline would grab your attention. Now that I have it, suffice it to say that there are plenty of caveats here. Nonetheless, when I saw the following headline from our friends at phys.org shared by Mr. B., I really did think that this might be yet the newest "modification" to come along that might lead to a reworking of the famous theory:
The title says it all: light doesn't move at certain exceptional points. The question is, what are those exceptional points? Well, this one is an epistemological noodle-baker for sure:
The researchers, Tamar Goldzak and Nimrod Moiseyev at the Technion – Israel Institute of Technology, along with Alexei A. Mailybaev at the Instituto de Matemática Pura e Aplicada (IMPA) in Rio de Janeiro, have published a paper on stopping light at exceptional points in a recent issue of Physical Review Letters.
As the researchers explain, exceptional points can be created in waveguides in a straightforward way, by varying the gain/loss parameters so that two light modes coalesce (combine into one mode). Although light stops at these exceptional points, in most systems much of the light is lost at these points. The researchers showed that this problem can be fixed by using waveguides with parity-time (PT) symmetry, since this symmetry ensures that the gain and loss are always balanced. As a result, the light intensity remains constant when the light approaches the exceptional point, eliminating losses.
To release the stopped light and accelerate it back up to normal speed, the scientists showed that the gain/loss parameters can simply be reversed. The most important feature of the new method, however, is that the exceptional points can be adjusted to work with any frequency of light, again simply by tuning the gain/loss parameters.
Now, I seem to remember something about Einstein talking about frames of reference and observers and so on, the gist of which was to maintain that the velocity of light was constant to every observer and any frame of reference. So the first thought I had when I read this was that the velocity of light drops to zero relative to what? In the article we're told that that this is achieved by certain times of wave guides that adjust gain and loss parameters with "parity--time symmetry." Whatever that means, and I'll take their word for it. But zero in reference to the waveguide? Presumably so. But the waveguide itself is still stuck on the laboratory tabletop, which is stuck to the ground of planet Earth, which is (the last time I checked) still moving around the Sun, which is still moving around the center of the galaxy... you get the idea.