p******e
发帖数: 58 | 1 1. there's no such things like 300*c in this
paper. (read the paper carefully please!)
there's only Ng=-310+-5 and -330+-30, which
corresponds to Vg=-c/310. As I realised, this
300*c appears only in public media, never in
the Nature paper!!!
For the '-' sign, I would rather take it as a
reflection propagating in opposite direction
(if this is still a valid discription, see 2),
so I don't agree with the interpretation in
the paper.
2. the definition of Vg used in this paper is
NOT valid for an | f*******d
发帖数: 339 | 2 You are right, Wang et al claimed that v_g=c/n_g, then they
say n_g=-310, so their velocity is much smaller than c. However,
they did say they have superluminal velocity in their paper,
so either they had completely confused themselves, or they had made a
typo, meant to say n_g=-1/310.
In either case, it is a shame for Nature to publish it as this without
caughting such mistake.
【在 p******e 的大作中提到】
: 1. there's no such things like 300*c in this
: paper. (read the paper carefully please!)
: there's only Ng=-310+-5 and -330+-30, which
: corresponds to Vg=-c/310. As I realised, this
: 300*c appears only in public media, never in
: the Nature paper!!!
: For the '-' sign, I would rather take it as a
: reflection propagating in opposite direction
: (if this is still a valid discription, see 2),
: so I don't agree with the interpretation in
| p******e
发帖数: 58 | 3
from the numbers in the paper, you can calculate and get that both
n_g=-330 and -310 are correct, and so they got v_g=-c/310 in their
experiment.
from page 278, dn, d(nu), lamda=852nm, ==> n_g=-330
from page 279, 6cm, 62ns, ==> v_g=-c/310 ==> n_g=-310
【在 f*******d 的大作中提到】
: You are right, Wang et al claimed that v_g=c/n_g, then they
: say n_g=-310, so their velocity is much smaller than c. However,
: they did say they have superluminal velocity in their paper,
: so either they had completely confused themselves, or they had made a
: typo, meant to say n_g=-1/310.
: In either case, it is a shame for Nature to publish it as this without
: caughting such mistake.
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