Is this what everyone else thinks the mysterious 'double trace' must be? I came across it in a paper on the standard model extension by A. Kostelecky and M. Mewes...
Does anyone have any other ideas about what they could be talking about?
OK that clears it up quite a bit, thanks for the help - I guess it really is true that a lot of these problems can be fixed just by thinking about what happens in the frame of the light you want to observe. Thanks! :)
This may have been answered in one of the quoted resources in this thread, but I have never been able to get my head around the following conundrum:
An observer external to the black hole will never see something cross the event horizon, yet someone falling in should be able to cross the...