EL:
(Bilge) wrote
in message ...
EL:
(Bilge)

I'm pointing out that articles which describe
some of the details in the papers I've seen referenced on this
forum may be found by searching for "rephasing" and "superluminal".
None of the papers mentioned so far actually describe what the
authors mean by "rephasing". The term is only referenced.

[EL]
Oh! But I did and all search take you into a full round fools picnic
and brings you back to where you started.

So, what about rephasing did you find to be s problem?

[EL]
How many new expressions do physicists have to invent to cover up
their asses?

What other expression does "rephasing" duplicate and what about the
phrase suggests anything about "covering asses"? To the contrary, I
don't see that it's "covering" anything except in the case that
someone mistakes the group velocity for the signal velocity.

If all that jumbled mumbles are about wave shapes then I still have
objections on claiming that a wave shape deformation can happen faster
than light because every local field vector that does not involve a
distance is not a speed, and any propagation is a function of the
parameters of the medium and have nothing to do with a wave shape.
This silly game is identical to here we go round the mulberry bush.

Then your objections are contradicted by a real experiment that
demonstrates the non-deformation of a gaussian pulse propagating
through cesium and arriving ahead of the same pulse in vacuum.

I strongly suggest that if you have some knowledge on the issue that
would add or change my stance you are strongly being encouraged to
bring it forth before I make my mind irreversibly on this matter.

What makes you think I have an opinion one way or the other
or really care whether you do?

[EL]
The thread is still on the record, and I did not invite you to give
the advice you gave willingly.

What does that have to do with what you assume my opinion about
the description of the phenomenon happens to be? You immediately
assumed something based only on me pointing out where additional
information might be found.

Giving such advice implies that you assume my ignorance of something
you know and that you so kindly felt that I should be educated.

Given your argument regarding group velocities, the assumption is
valid since you aren't talking about the same thing as the authors,
who differentiate between signal velocity and group velocity. If
you wish to take that as some slight to your manhood, ok. There's
nothing I can do about that. I usually read the material someone
suggests rather than looking for my dueling pistols under the
assumption the reference was a glove being slapped in my face.

(Bilge) wrote in message ...

[EL]
How many new expressions do physicists have to invent to cover up
their asses?

What other expression does "rephasing" duplicate and what about the
phrase suggests anything about "covering asses"? To the contrary, I
don't see that it's "covering" anything except in the case that
someone mistakes the group velocity for the signal velocity.

[EL]
Take wave shape reshaping where reshaping is a word found in
dictionaries.
Please do not imply that {phase} is not common knowledge here.
We all know what are phase-lag, phase-lead, and phase-shift etcetera
so we are talking about the same thing here. Any manipulation in the
phase of a wave is a wave reshaping so why do they have to obscure the
issue by creating a new word unless they intentionally are obscuring
rather than explaining?
Yes they are covering their asses and I am not confusing a
wave-modulation-envelope's velocity with signal velocity as much as
you seem to wish to imply.


If all that jumbled mumbles are about wave shapes then I still have
objections on claiming that a wave shape deformation can happen faster
than light because every local field vector that does not involve a
distance is not a speed, and any propagation is a function of the
parameters of the medium and have nothing to do with a wave shape.
This silly game is identical to here we go round the mulberry bush.

Then your objections are contradicted by a real experiment that
demonstrates the non-deformation of a gaussian pulse propagating
through cesium and arriving ahead of the same pulse in vacuum.

[EL]
I strongly protest to your twisting of the facts here.
Some morons made an experiment and falsely claimed claims to which I
have objections and not the other way around as you deliberately put
to confuse the readers.
It is not my objections that are being refuted but it is the wild
claims which I am refuting here.
You obviously did not read all my posts on this topic and that is why
you have no clue on the evidences I have presented so far. I
practically tore that experiment to pieces Bilge so hold your horses
before you get deeper or involved. I know your high calibre and your
solid knowledge, and I hate being in opposition with you, so take my
advise and hold your horses right there.

EL

A possible way to distinguish between the explanation that a leading
portion of the starting pulse allows the full pulse to be
reconstructed at the endpoint before the full pulse enters the chamber
and the explanation that the use of light speed EM signals causes the
starting point and endpoint to be missynchronized might be to reflect
back the pulse to the starting point.
If the leading portion idea is correct then both the forward and
return pulses should be time shifted ahead so the return pulse should
return to the start 124 nanoseconds before the starting pulse fully
enters the chamber.
If standard special relativity synchronization is incorrect then in
fact the return pulse will return to the start *after* the start pulse
enters the chamber.


Bob Clark


(Robert Clark) wrote in message
...
The original paper in Nature is available he

Gain-assisted superluminal light propagation.
L. J. Wang, A. Kuzmich & A. Dogariu
NEC Research Institute, 4 Independence Way, Princeton, New Jersey
08540, USA
NATURE, VOL 406, 20 JULY 2000, p. 277-279.
http://www.physik.uni-stuttgart.de/i...2001-chien.pdf

A passage on page 278 suggests the departure points and arrival
points have to be time synchronized:

"A high-sensitivity avalanche photodiode,
reverse-biased below breakdown, serves as detector D2 to measure
the weak probe pulse that propagates through the atomic cell. The
photoelectric current produced by detector D2 is converted to a
voltage signal using a 500-Q load resistor and recorded by a
digitizing oscilloscope using a synchronized output signal from
the pulse generator as the trigger."
Gain-assisted superluminal light propagation, p. 278


The equations that you cited I think are actually in a more detailed
examination that is available on lead author Lijun Wang's web site:

Superluminal Light Pulse Propagation at a
Negative Group Velocity.
http://www.neci.nec.com/homepages/lw...er/paper46.pdf

The equations you cited used greek letters that didn't show up in the
usenet post. I'll use the letter w to represent the frequency that
appears in the first equation you cited. Then the equation says:

Vg = c/(n + wdn/dw) , where Vg is group velocity, c is light speed, n
is refractive index and w is frequency.
The researchers were able to achieve superluminal group velocity by
making the derivative dn/dw highly negative, that is, the refractive
index rapidly decreases as the frequency increases.
They explain their work simply he

Detailed statement on faster-than- c light pulse propagation.
http://www.nec.co.jp/press/en/0007/images/1901.pdf

Here they explain that the laser pulse exited the 6 cm long cesium
chamber 62 nanoseconds sooner than if the laser traveled the 6 cm in
vacuum. Since it takes only 0.2 nanoseconds for light to traverse 6 cm
in vacuum, this means the pulse exited the chamber before it entered
it.
The suggested explanation for this effect is that some portion of the
entering pulse reaches the end detector before the full pulse enters
the chamber from which the full pulse was reconstructed. This
explanation however could be applied whenever you did get a result
that suggested the pulse traveled superluminally.
An improved test to see if the signal is traveling superluminally
might be to use a longer chamber 100 meters long for example. Light
takes 330 nanoseconds to traverse this length. In the first experiment
the authors say the exiting pulse traveled 20 meters before the
starting pulse entered the chamber. If the time shift is the same in
the 100 meter long chamber, the exiting pulse should leave after the
starting pulse enters this time. Then you could see if the travel time
is less than that for light in vacuum. You might still be able to
argue that what is happening is some portion of the starting pulse is
being transmitted early to the end detector, but it won't really
matter if it still provides a means of signaling in a shorter time
that light signals would take.



Bob Clark

[EL]
I decided not to be mean to you and tell you that you posted
gibberish.
That is why I made the effort to un-riddle your obscure linguistic
constructs.
Giving you the benefit of the doubt I shall interleave my comments.

(Robert Clark) wrote in message . com...
A possible way to distinguish between the explanation that a leading
portion of the starting pulse

[EL]
I hate cuttoning a long sentence or shredding a meaning into pieces
but your gibberish is forcing me.
Oops, sorry.
You "say a leading portion of a starting pulse".
Why is it not simply a wavefront!
Starting pulse implies an ending pulse, or did you mean the pulse
begining which is the leading portion which is the wavefront?

allows the full pulse to be reconstructed

[EL]
Reconstructed implied deconstructed, which you forgot to explain.
A dispersive medium is well known to dismantle a group-wave into its
components due to the different velocities of different frequencies on
condition that the angle of incidence of the wave-packet is not normal
to the surface of the medium such that the different refractive
indexes cause different paths at different angles for each frequency
component.
Now that we know how the wave-packet is deconstructed, how do you
suggest reconstruction by other means else than magic please?

at the endpoint before the full pulse enters the chamber

[EL]
I beseech your sanity if you have any such sanity to tell me how you
could imagine this insane causality scheme.
Let us replace "the full pulse" by letter P.
You say that P shows up at the endpoint before P enters the chamber!

A room with a door and a wall ahead of the door inside the room and
you imply that a person P would touch the wall inside the room ahead
of the door before even opening the door!

If that insane jumbled mumbles are not what I protest to be the most
reckless pseudo-scientific claims then what else could break the
record of being more insane?


and the explanation that the use of light speed EM signals causes the
starting point and endpoint to be missynchronized might be to reflect
back the pulse to the starting point.

[EL]
Now you started to describe wanton fiddling with a device and not a
respectable scientific experiment.

If the leading portion idea is correct then both the forward and
return pulses should be time shifted ahead so the return pulse should
return to the start 124 nanoseconds before the starting pulse fully
enters the chamber.

[EL]
This is typical nonsense, because the wave-packet's wavefront proceeds
from the splitter and enters an infinitesimal length in both of the
chambers, the caesium and the vacuum at the same time. This means that
within 0.2 ns the vacuum chamber output must be concluded, expected
and measured empirically and you have not ONE SINGLE COMPLETE
nanosecond to claim a whole lot of 124 nanoseconds that you never had.

If standard special relativity synchronization is incorrect then in
fact the return pulse will return to the start *after* the start pulse
enters the chamber.


Bob Clark

[EL]
SR and GR are being introduced here as a salvation of the fallacy
which is founded on a classic error that overlooked the fact that time
could not be rewound negatively.

Negative time is a descriptive issue of the past as remembered at some
point in the future but we cannot apply negative time operationally to
conclude any time travel or back-causality or time-reversal.

So claiming that time could go negative is very stupid and usually
made by superficial minds and clowns.

Wake up people, and if SR and GR did preach such lunatic ideas then I
have to denounce those theories as the cause of the dark ages of
physics in which we live today.

EL

The explanation that has been proposed for how a full pulse can arrive
at the end before the *full* pulse enters the chamber is given in this
NY Times story:

May 30, 2000
Light Exceeds Its Own Speed Limit, or Does It?
By JAMES GLANZ
"As most physicists interpret the experiment, it is a low-intensity
precursor (sometimes called a tail, even when it comes first) of the
incoming wave that clues the cesium chamber to the imminent arrival of
a pulse. In a process whose details are poorly understood, but whose
effect in Dr. Wang's experiment is striking, the cesium chamber
reconstructs the entire pulse solely from information contained in the
shape and size of the tail, and spits the pulse out early.
"If the side of the chamber facing the incoming wave is called the
near side, and the other the far side, the sequence of events is
something like the following. The incoming wave, its tail extending
ahead of it, approaches the chamber. Before the incoming wave's peak
gets to the near side of the chamber, a complete pulse is emitted from
the far side, along with a backward wave inside the chamber that moves
from the far to the near side."
http://www.nytimes.com/library/natio...ics-light.html

It is a mathematical fact that a highly smooth pulse (the technical
term is analytic) such as a Gaussian pulse can be completely
reconstructed from any portion of the pulse.

What this hypothesized explanation is proposing is illustrated in the
diagram below:

_______________
| |
/\ | |
/ \ | |
----/ \---- |_______________|


_______________
| |
/\ | |
/ \| |\
----/ |_______________| \----


_______________
| |
/\| | /\
/ | | / \
----/ |_______________|-/ \----


(You may need to used a fixed-width font such as Courier to view this
diagram properly.)

Then if the pulse position is determined by the peak, the pulse is
seen as exiting the chamber before it enters. But actually what
happens, according to this explanation, is that a lead portion of the
beginning pulse enters the chamber, travels at normal light speed, and
reconstructs the full pulse when it reaches the other side. So no
superluminal or backwards in time transmission of information occurs.
My suggested experiment to decide between this explanation and the
explanation that there is really superluminal *signal* tranmission
implying a varying *one-way* speed of light can also be illuminated by
the above diagram. As you can see in the middle figure of the diagram
the lead portion of the exit pulse also exits the chamber before the
full pulse exits and since the pulse shape is unchanged it leads by
the same amount as with the starting pulse. So this leading exiting
portion leads the exiting full pulse by the same amount about 62
nanoseconds. Then the leading exiting portion in fact leads the
entrance of the full starting pulse by twice this, 124 nanoseconds.
Then if we reflect this back to the start since the light speed travel
time is so short about .2 nanoseconds, this returning lead pulse
should also create a full pulse back at the starting side, at about
124 nanoseconds before the full starting pulse enters the chamber.
On the other hand according the superluminal signal transmission
explanation, the observation of the exit pulse leaving the chamber at
an earlier *measured* time than the entrance of the start pulse is
simply due to the exit and entrance not being properly synchronized by
EM light speed signals. So it is, according to this explanation, the
actual full pulse that is being transmitted from the start to the end.
Then in this case when you reflect the end pulse back to the start it
should arrive *after* the start pulse has entered.


I had thought that the accepted explanation of a leading portion of
the start pulse creating the early exit pulse was purely hypothetical
since no one had actually seen what was happening in the chamber.
However, I just found an article describing such a leading pulse
called a Sommerfeld precursor or forerunner in material surface waves
:

Observation of Sommerfeld Precursors on a Fluid Surface.
"We report the observation of two types of Sommerfeld precursors (or
forerunners) on the surface of a layer of mercury.When the fluid depth
increases, we observe a transition between these two precursor surface
waves in good agreement with the predictions of asymptotic analysis.
At depths thin enough compared to the capillary length, high frequency
precursors propagate ahead of the ‘‘main signal'' and their period and
amplitude, measured at a fixed point, increase in time. For larger
depths, low frequency ‘‘precursors'' follow the main signal with a
decreasing period and amplitude. These behaviors are understood in the
framework of the analysis first introduced for linear transient
electromagnetic waves in a dielectric medium by Sommerfeld [Ann. Phys.
(Leipzig) 44, 177 (1914)] and Brillouin [Ann. Phys.(Leipzig) 44, 203
(1914)]."
PHYSICAL REVIEW LETTERS.
8 AUGUST 2003 VOLUME 91, NUMBER 6
http://www.ens-lyon.fr/~efalcon/prl03/PRL03.pdf



Bob Clark


-------------------------------------------------------------
For email response, send to same userid as above, but append
Hotmail.com instead of Yahoo.com.
-------------------------------------------------------------

(EL) wrote in message . com...
[EL]
I decided not to be mean to you and tell you that you posted
gibberish.
That is why I made the effort to un-riddle your obscure linguistic
constructs.
Giving you the benefit of the doubt I shall interleave my comments.

(Robert Clark) wrote in message . com...
A possible way to distinguish between the explanation that a leading
portion of the starting pulse

[EL]
I hate cuttoning a long sentence or shredding a meaning into pieces
but your gibberish is forcing me.
Oops, sorry.
You "say a leading portion of a starting pulse".
Why is it not simply a wavefront!
Starting pulse implies an ending pulse, or did you mean the pulse
begining which is the leading portion which is the wavefront?

allows the full pulse to be reconstructed

[EL]
Reconstructed implied deconstructed, which you forgot to explain.
A dispersive medium is well known to dismantle a group-wave into its
components due to the different velocities of different frequencies on
condition that the angle of incidence of the wave-packet is not normal
to the surface of the medium such that the different refractive
indexes cause different paths at different angles for each frequency
component.
Now that we know how the wave-packet is deconstructed, how do you
suggest reconstruction by other means else than magic please?

at the endpoint before the full pulse enters the chamber

[EL]
I beseech your sanity if you have any such sanity to tell me how you
could imagine this insane causality scheme.
Let us replace "the full pulse" by letter P.
You say that P shows up at the endpoint before P enters the chamber!

A room with a door and a wall ahead of the door inside the room and
you imply that a person P would touch the wall inside the room ahead
of the door before even opening the door!

If that insane jumbled mumbles are not what I protest to be the most
reckless pseudo-scientific claims then what else could break the
record of being more insane?


and the explanation that the use of light speed EM signals causes the
starting point and endpoint to be missynchronized might be to reflect
back the pulse to the starting point.

[EL]
Now you started to describe wanton fiddling with a device and not a
respectable scientific experiment.

If the leading portion idea is correct then both the forward and
return pulses should be time shifted ahead so the return pulse should
return to the start 124 nanoseconds before the starting pulse fully
enters the chamber.

[EL]
This is typical nonsense, because the wave-packet's wavefront proceeds
from the splitter and enters an infinitesimal length in both of the
chambers, the caesium and the vacuum at the same time. This means that
within 0.2 ns the vacuum chamber output must be concluded, expected
and measured empirically and you have not ONE SINGLE COMPLETE
nanosecond to claim a whole lot of 124 nanoseconds that you never had.

If standard special relativity synchronization is incorrect then in
fact the return pulse will return to the start *after* the start pulse
enters the chamber.


Bob Clark

[EL]
SR and GR are being introduced here as a salvation of the fallacy
which is founded on a classic error that overlooked the fact that time
could not be rewound negatively.

Negative time is a descriptive issue of the past as remembered at some
point in the future but we cannot apply negative time operationally to
conclude any time travel or back-causality or time-reversal.

So claiming that time could go negative is very stupid and usually
made by superficial minds and clowns.

Wake up people, and if SR and GR did preach such lunatic ideas then I
have to denounce those theories as the cause of the dark ages of
physics in which we live today.

EL

EL:
(Robert Clark) wrote in message
.com...

Here they explain that the laser pulse exited the 6 cm long cesium
chamber 62 nanoseconds sooner than if the laser traveled the 6 cm in
vacuum. Since it takes only 0.2 nanoseconds for light to traverse 6 cm
in vacuum, this means the pulse exited the chamber before it entered
it.

[EL]
My problem with those supposedly scientists is that they do not feel
ashamed to say that nonsense and repeat it as if it was so normal
logic and they claim with boldness that it does not violate causality.
If that nonsense did not violate causality then what else does?


Bilge replied:
You actually have to read several of their papers to figure out what
they mean. The buzzword used is "rephasing". It's not clear to me that
"superluminal" applies to a signal that can carry information, or at least
carry information superluminally. The papers show some plots that give a
better idea of what's going on, but it's too hard to try and reproduce
them or describe them here. Search for "rephasing" and "superluminal"

Having actually read some of their papers a while ago they freely admit that
their results in no way violate either SR or QM - indeed it is predicted by
it. Thus they can not send information faster than light - casualty
guarantees it.

Thanks
Bill

"Bill Hobba" wrote in message ...
EL:
(Robert Clark) wrote in message
.com...

Here they explain that the laser pulse exited the 6 cm long cesium
chamber 62 nanoseconds sooner than if the laser traveled the 6 cm in
vacuum. Since it takes only 0.2 nanoseconds for light to traverse 6 cm
in vacuum, this means the pulse exited the chamber before it entered
it.

[EL]
My problem with those supposedly scientists is that they do not feel
ashamed to say that nonsense and repeat it as if it was so normal
logic and they claim with boldness that it does not violate causality.
If that nonsense did not violate causality then what else does?


Bilge replied:
You actually have to read several of their papers to figure out what
they mean. The buzzword used is "rephasing". It's not clear to me that
"superluminal" applies to a signal that can carry information, or at least
carry information superluminally. The papers show some plots that give a
better idea of what's going on, but it's too hard to try and reproduce
them or describe them here. Search for "rephasing" and "superluminal"

Having actually read some of their papers a while ago they freely admit that
their results in no way violate either SR or QM - indeed it is predicted by
it. Thus they can not send information faster than light - casualty
guarantees it.

Thanks
Bill

[EL]
So Sam tells to you that he was already an adult before his father was
born and that that fact does not violate SR or QM and indeed is
predicted by them. Also he may not walk or run faster than his younger
father and that that is guaranteed by [sic] casualty not causality.

So you believe Sam because he said so!
Even if you can obviously see that Sam was full of ****!

How about the equations I have demonstrated!
They made an error by mimicking a classical theoretical error that was
never verified then and certainly is not being verified now.
The error is taking negative time from negative slopes of
delta-lambda/delta-velocity to be subtracted rather than added to the
total time required for the completion of a change of state.
This error is hidden in the jargon of:

u = v – (L (dv/dL))

where u is the group velocity, v is the phase velocity, L is the
wavelength, dv is the difference between wave packet components'
velocities and dL is the difference between their wavelengths.

A negative slope means a negative frequency!
A negative frequency is the inverse of a negative time.
There is no negative frequency because frequency is a count of
integers per unit of proper time.

The correct mathematical formula is:

u = v – (L (|dv/dL|))

There is no physical meaning for the moronic label "negative
dispersion".
A negative slope still takes an absolute quantity of time to happen.

So there is no superluminal speed at all to be in agreement or
disagreement with SR, GR, QM or any other system whatsoever.

To verify the logic, draw a proper time line and mark a time window to
be the proper Time Frame of the experiment. Inside that Time Frame
draw the intervals of every time period in which a sequence of events
took place. Conclude your logical conclusions from paper and not from
dreams, please.

EL

Microsoft Outlook Express uses a proportional font by default in
reading newsgroup messages. To properly view the diagram below in OE,
you need to tell it to use a fixed-width font such as Courier: go to
Tools - Options...- Read - Fonts ... Then choose actually a
fixed-width font such as Courier in the pull-down list under the box
for the Proportional Font.

Or you can read the post he

From: Robert Clark )
Subject: Empirically Confirmed Superluminal Velocities?
Newsgroups: sci.physics.relativity, alt.sci.physics.new-theories,
sci.physics, sci.astro
Date: 2003-11-07 11:49:03 PST
http://groups.google.com/groups?selm...g .google.com

The diagram itself I took from the article:

"Slow" and "Fast" Light.
by Robert W. Boyd and Daniel J. Gauthier
http://www.phy.duke.edu/research/pho...ssInOptics.pdf

It appears in Fig. 1 on page 21.

The conclusion that under the accepted explanation the exiting
Sommerfeld precursor reflected back reaches the start 124 nanoseconds
before the start peak reaches the chamber is puzzling however. This
would also seem to mean that this reflected precursor reaches the
start *before* the precursor of the start pulse as well. But it is
this precursor of the start pulse that is supposed to get the process
going to begin with. Then you are back to a causality problem.
I tried making the precursor of the start pulse arrive at the chamber
shorter or longer than 62 nanoseconds before the start peak but I
still keep coming back to the conclusion that the reflected precursor
arrives at the start before the starting precursor.
The only thing I can think, following the accepted explanation, is
that the exiting pulse really does not look just like the entering
pulse. It would for example not have that leading exiting portion. But
this should be visible in the shape of the exiting pulse if true. The
exiting pulse would be chopped off at the front.


Bob Clark


-------------------------------------------------------------
For email response, send to same userid as above, but append
Hotmail.com instead of Yahoo.com.
-------------------------------------------------------------

(Robert Clark) wrote in message . com...
The explanation that has been proposed for how a full pulse can arrive
at the end before the *full* pulse enters the chamber is given in this
NY Times story:

May 30, 2000
Light Exceeds Its Own Speed Limit, or Does It?
By JAMES GLANZ
"As most physicists interpret the experiment, it is a low-intensity
precursor (sometimes called a tail, even when it comes first) of the
incoming wave that clues the cesium chamber to the imminent arrival of
a pulse. In a process whose details are poorly understood, but whose
effect in Dr. Wang's experiment is striking, the cesium chamber
reconstructs the entire pulse solely from information contained in the
shape and size of the tail, and spits the pulse out early.
"If the side of the chamber facing the incoming wave is called the
near side, and the other the far side, the sequence of events is
something like the following. The incoming wave, its tail extending
ahead of it, approaches the chamber. Before the incoming wave's peak
gets to the near side of the chamber, a complete pulse is emitted from
the far side, along with a backward wave inside the chamber that moves
from the far to the near side."
http://www.nytimes.com/library/natio...ics-light.html

It is a mathematical fact that a highly smooth pulse (the technical
term is analytic) such as a Gaussian pulse can be completely
reconstructed from any portion of the pulse.

What this hypothesized explanation is proposing is illustrated in the
diagram below:

_______________
| |
/\ | |
/ \ | |
----/ \---- |_______________|


_______________
| |
/\ | |
/ \| |\
----/ |_______________| \----


_______________
| |
/\| | /\
/ | | / \
----/ |_______________|-/ \----


(You may need to used a fixed-width font such as Courier to view this
diagram properly.)

Then if the pulse position is determined by the peak, the pulse is
seen as exiting the chamber before it enters. But actually what
happens, according to this explanation, is that a lead portion of the
beginning pulse enters the chamber, travels at normal light speed, and
reconstructs the full pulse when it reaches the other side. So no
superluminal or backwards in time transmission of information occurs.
My suggested experiment to decide between this explanation and the
explanation that there is really superluminal *signal* tranmission
implying a varying *one-way* speed of light can also be illuminated by
the above diagram. As you can see in the middle figure of the diagram
the lead portion of the exit pulse also exits the chamber before the
full pulse exits and since the pulse shape is unchanged it leads by
the same amount as with the starting pulse. So this leading exiting
portion leads the exiting full pulse by the same amount about 62
nanoseconds. Then the leading exiting portion in fact leads the
entrance of the full starting pulse by twice this, 124 nanoseconds.
Then if we reflect this back to the start since the light speed travel
time is so short about .2 nanoseconds, this returning lead pulse
should also create a full pulse back at the starting side, at about
124 nanoseconds before the full starting pulse enters the chamber.
On the other hand according the superluminal signal transmission
explanation, the observation of the exit pulse leaving the chamber at
an earlier *measured* time than the entrance of the start pulse is
simply due to the exit and entrance not being properly synchronized by
EM light speed signals. So it is, according to this explanation, the
actual full pulse that is being transmitted from the start to the end.
Then in this case when you reflect the end pulse back to the start it
should arrive *after* the start pulse has entered.


I had thought that the accepted explanation of a leading portion of
the start pulse creating the early exit pulse was purely hypothetical
since no one had actually seen what was happening in the chamber.
However, I just found an article describing such a leading pulse
called a Sommerfeld precursor or forerunner in material surface waves
:

Observation of Sommerfeld Precursors on a Fluid Surface.
"We report the observation of two types of Sommerfeld precursors (or
forerunners) on the surface of a layer of mercury.When the fluid depth
increases, we observe a transition between these two precursor surface
waves in good agreement with the predictions of asymptotic analysis.
At depths thin enough compared to the capillary length, high frequency
precursors propagate ahead of the ??main signal'' and their period and
amplitude, measured at a fixed point, increase in time. For larger
depths, low frequency ??precursors'' follow the main signal with a
decreasing period and amplitude. These behaviors are understood in the
framework of the analysis first introduced for linear transient
electromagnetic waves in a dielectric medium by Sommerfeld [Ann. Phys.
(Leipzig) 44, 177 (1914)] and Brillouin [Ann. Phys.(Leipzig) 44, 203
(1914)]."
PHYSICAL REVIEW LETTERS.
8 AUGUST 2003 VOLUME 91, NUMBER 6
http://www.ens-lyon.fr/~efalcon/prl03/PRL03.pdf



Bob Clark


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[EL]
Let me help you and the readers by proposing a much more tenable
scenario Robert.

Assume that the experimenters used a symmetrical wave the wavelength
of which is about 38 meters long or anything approximately oscillating
at 8MHz (These values are very rough and just for demonstration).

Assume that the wave shape is symmetrical and that the wavefront has
the minimum amplitude but the maximum tare of amplitude change of
state. The maximum amplitude is at the centre of the wave.

Now let that wave enter the chamber and propagate at c and the
wavefront reaches the far end after exactly 0.2 nanoseconds but the
detector translates the maximum rate of change of the amplitude to a
maximum output amplitude, and the wavefront thus triggers the timer to
register the arrival of the wave-peak, which did not yet enter the
chamber, which when on entering the chamber triggers the near end
detector of a wave peak about 62 nanoseconds which is half the full
period of the wave.

In other words it could be a clumsy mistake or a deliberate foul play
with experimental results.

If those experimenters were serious, they must repeat the same
experiment showing the arrival time being ahead by 31 nanoseconds when
they double the frequency of the wave being transmitted and 124
nanoseconds when the frequency is halved or the wavelength doubled.

Then my scenario should make full sense and they should discard the
relevance of their experiment for any proof of a superluminal speed.

A much better experiment is to send a square wave pulse from a
chopper.
In that scenario the wave front is the same as the maximum rate of
change in the amplitude.
The body of the wave having a constant amplitude shall not induce
changes at the far end until the falling edge arrives and produces a
second peak. This frequency doubler shall prove my suspicions and give
them accurate time of the arrival of each edge and by the knowledge of
the wavelength the velocity may be calculated.

As far as I know and am sure of my knowledge in electronics that
somewhere in there measuring system there is an inverter that reports
the inverse of the wave amplitude at the caesium far end while it
reports a none-inverted wave amplitude at the vacuum far end.

This might explain what you meant by wave-reshaping or the weird
expression of rephasing.

In any case of which I have presented, there is no superluminal
propagation of anything but we do have a screwed up experiment with
results prepared before experimenting.

To fully understand what I am explaining here you need access to the
full specifications of the caesium cell, wave splitters, the vacuum
cell, the wave detector integrated circuit and if its part number
causes inversion or not and its sensitivity curves and the length of
leads and the recording of data and the acquisition methods.

After studying the specifications of the device you may proceed to
inspect the data that was recorded before any mathematical
manipulation of that data.

Kind regards.

EL






(Robert Clark) wrote in message . com...
Microsoft Outlook Express uses a proportional font by default in
reading newsgroup messages. To properly view the diagram below in OE,
you need to tell it to use a fixed-width font such as Courier: go to
Tools - Options...- Read - Fonts ... Then choose actually a
fixed-width font such as Courier in the pull-down list under the box
for the Proportional Font.

Or you can read the post he

From: Robert Clark )
Subject: Empirically Confirmed Superluminal Velocities?
Newsgroups: sci.physics.relativity, alt.sci.physics.new-theories,
sci.physics, sci.astro
Date: 2003-11-07 11:49:03 PST
http://groups.google.com/groups?selm...g .google.com

The diagram itself I took from the article:

"Slow" and "Fast" Light.
by Robert W. Boyd and Daniel J. Gauthier
http://www.phy.duke.edu/research/pho...ssInOptics.pdf

It appears in Fig. 1 on page 21.

The conclusion that under the accepted explanation the exiting
Sommerfeld precursor reflected back reaches the start 124 nanoseconds
before the start peak reaches the chamber is puzzling however. This
would also seem to mean that this reflected precursor reaches the
start *before* the precursor of the start pulse as well. But it is
this precursor of the start pulse that is supposed to get the process
going to begin with. Then you are back to a causality problem.
I tried making the precursor of the start pulse arrive at the chamber
shorter or longer than 62 nanoseconds before the start peak but I
still keep coming back to the conclusion that the reflected precursor
arrives at the start before the starting precursor.
The only thing I can think, following the accepted explanation, is
that the exiting pulse really does not look just like the entering
pulse. It would for example not have that leading exiting portion. But
this should be visible in the shape of the exiting pulse if true. The
exiting pulse would be chopped off at the front.


Bob Clark

EL:

Now let that wave enter the chamber and propagate at c and the
wavefront reaches the far end after exactly 0.2 nanoseconds but the
detector translates the maximum rate of change of the amplitude to a
maximum output amplitude, and the wavefront thus triggers the timer to
register the arrival of the wave-peak, which did not yet enter the
chamber, which when on entering the chamber triggers the near end
detector of a wave peak about 62 nanoseconds which is half the full
period of the wave.

A constant fraction discriminator solves that problem and is one of
the most common, if not the most common method of obtaining timing marks
which are independent of rise time and amplitude. Timing considerations
are such a crucial part of any experiment that no experimental physicist
would make such a mistake.

A cfd works by splitting an input signal, inverting one of those,
delaying it slightly, adding it to the non-inverted signal and
taking the zero crossing of the summed signal as the timing mark,
which is then output as a digital pulse (typically NIM).

[...]

As far as I know and am sure of my knowledge in electronics that
somewhere in there measuring system there is an inverter that reports
the inverse of the wave amplitude at the caesium far end while it
reports a none-inverted wave amplitude at the vacuum far end.

A standard way of determining the timing of two pulses is the
following:

+--------------- analog pulse data
|
------+-|cfd|-|TAC|-- timing information
In 1

+--------------- analog pulse data
|
------+-|cfd|-|TAC|-- timing information
In 2

Or some variation on that theme. A time-to-digital converter or
time-to-amplitude (TAC) converter follows the constant fraction
discriminator. The analog pulse data are then completely irrelevant
for timing information. All of the timing information is in a time
spectrum. It's trivial to get time resolution at a resolution of
a couple of nseconds. It's possible to better than 1 ns by being
careful and using a good cfd and TAC. Propagation times are always
matched to account for any differences due to cable delays or elec-
tronics. If anything, they would have a set up that is better than
this, not worse, since this is very basic.