4 ms·
“The 3-microsecond long pulse of light would normally take only 0.2 nanoseconds to pass through the chamber in a vacuum. But when passed through the specially p
by fallingfrog 5y ago
“The 3-microsecond long pulse of light would normally take only 0.2 nanoseconds to pass through the chamber in a vacuum. But when passed through the specially prepared chamber, light emerged 62 nanoseconds earlier than it would have had it passed through the chamber in a vacuum.”
So, the pulse emerged 61.8 ns before it entered? It traveled backwards in time? Seems like there’s a typo somewhere.
- EGreg 5y agoYes from the point of view of observers. From the Nature article abstract: "in practice, this means that a light pulse propagating through the atomic vapour cell appears at the exit side so much earlier than if it had propagated the same distance in a vacuum that the peak of the pulse appears to leave the cell before entering it. "
- maxk42 5y agoNo, I think what it's saying is a pulse of duration 3000ns arrived at its destination over the course of 2938.2ns.
- fallingfrog 5y agoOh ok. Maybe there’s some confusion over the meaning of “emerged” then. I interpret “emerged” as “when the leading edge first becomes detectable coming out”.