4 ms·
Phase velocity vs group velocity. But it's pretty easy to check that everything is alright with group velocity. If there is zero neutrino production at t=0 (in
by Florin_Andrei 15y ago
Phase velocity vs group velocity.
But it's pretty easy to check that everything is alright with group velocity. If there is zero neutrino production at t=0 (in the reactor's frame of reference), and then the production jumps up, there can be no doubt about the group velocity.
Bizarre effects relative to superluminal phase velocity only appear when you start generating particles before t=0 and you mess with the medium in between. Then the "superluminal" illusion is created by quanta created before t=0.
TLDR: I find it bizarre that seasoned professionals could be fooled by phase velocity or a similar effect.
- DenisM 15y agoPhase velocity vs group velocity. Yes, thank you. Why did it take me so many words? :)
- mirkules 15y agoI'm glad that it did take you so many words. I remember reading about this a while back, but could never remember what it was called, or why the light particles actually didn't break the speed barrier. I really appreciate your laymen explanation, and now, thanks to you parent, also know what the effect is called.
- Florin_Andrei 15y agoThink of the wagon wheels, as seen in a western movie, turning back, or moving at bizarre speeds in either direction. It's not a perfect analogy, but it's a related phenomenon.
- 0x12 15y agoThat's called aliasing.
- Florin_Andrei 15y agoWell, you gave the layman's explanation. Not everyone is well versed in these specific terms.