Light stopped in its tracks.
S D Rodent
January 18, 2001
Scientists Bring Light to Full Stop, Hold
It, Then Send It on Its Way
By JAMES GLANZ
Researchers say they have
slowed light to a dead stop,
stored it and then released it as if it
were an ordinary material particle.
To quote S D Rodrian:
http://web.sdrodrian.com
"... In reality what they did
was to "pressure" the photon
into such proximity with the
gas atoms that they were
captured gravitationally: This
is a way of saying that the atoms
(which are the ones that are really
"moving" at the speed of light (not
the photons) "grabbed" the photons
and dragged them along (which
speeding up of the photon to "our"
greater speed we naturally interpret
as "slowing down" to "our" state of
"motionlessness." If, as incorrectly
described in the article, the photon
would have really been brought to
a "stop" it would have: 1) not stopped
relative to us, of course, because we
(the universe's ordinary matter) are
always in perpetual relative motion,
and this means for all practical purposes
that the "stopped" photon is ALSO
being "dragged about all over the place"
along with us to make it seem to be at
rest relative to us. [Again confirming my
proposal that the photon "only" "moves"
in a straight trajectory relative to the
rest of the universe (i.e. ... a trajectory
determined by gravity), but also reaffirms
Einstein's already proved proposal that
a strong-enough gravitational field will
"grab" the photon as well (if not as
"much") as it will grab any of the other
particles of ordinary matter.] And, 2) the
fact that a "man-made box" can drag a
photon about as readily as it can "carry
in it" any other article... illustrates better
than any other presentation could: not only
that it IS the "box" that is "moving" and
NOT the photon, but that the photon is NOT
merely "vibrating" (traveling "back & forth"
and therefore simply taking a longer path)
still at the speed of light but is actually
"captured" [energy=motion, therefore its
energy is being conserved IN "motions" which
have been "written] into" the captivating
atoms... in an analogous fashion not all
that much different from a body captured in
orbit (e.g. the addition/conservation of
energy/motion/mass." --SDR
The achievement is a landmark
feat that, by reining in nature's
swiftest and most ethereal form of
energy for the first time, could help
realize what are now theoretical
concepts for vastly increasing the
speed of computers and the
security of communications.
Two independent teams of
physicists have achieved the result,
one led by Dr. Lene Vestergaard
Hau of Harvard University and the
Rowland Institute for Science in
Cambridge, Mass., and the other
by Dr. Ronald L. Walsworth and
Dr. Mikhail D. Lukin of the
Harvard-Smithsonian Center for
Astrophysics, also in Cambridge.
Light normally moves through
space at 186,000 miles a second.
Ordinary transparent media like
water, glass and crystal slow light
slightly, an effect that causes the
bending of light rays that allows
lenses to focus images and prisms
to produce spectra.
Using a distantly related but much
more powerful effect, the
Walsworth-Lukin team first
slowed and then stopped the light
in a medium that consisted of
specially prepared containers of
gas. In this medium, the light
became fainter and fainter as it
slowed and then stopped. By
flashing a second light through the
gas, the team could essentially
revive the original beam.
The beam then left the chamber
carrying nearly the same shape,
intensity and other properties it had when
it entered. The experiments led by Dr. Hau
achieved similar results with
closely related techniques.
"Essentially, the light becomes stuck in
the medium, and it can't get out
until the experimenters say so," said
Dr. Seth Lloyd, an associate
professor of mechanical engineering
at the Massachusetts Institute of
Technology who is familiar with the work.
Dr. Lloyd added, "Who ever thought that
you could make light stand still?"
He said the work's biggest impact could
come in futuristic technologies
called quantum computing and quantum
communication. Both concepts
rely heavily on the ability of light
to carry so-called quantum information,
involving particles that can exist in
many places or states at once.
Quantum computers could crank through
certain operations vastly faster
than existing machines; quantum
commmunications could never be
eavesdropped upon. For both these
systems, light is needed to form
large networks of computers. But
those connections are difficult without
temporary storage of light, a problem
that the new work could help solve.
A paper by Dr. Walsworth, Dr. Lukin
and three collaborators — Dr. David Phillips,
Annet Fleischhauer and Dr. Alois Mair, all at
Harvard-Smithsonian — is scheduled to appear
in the Jan. 29 issue of Physical Review Letters.
Citing restrictions imposed by the
journal Nature, where her report is to
appear, Dr. Hau refused to discuss
her work in detail.
Two years ago, however, Nature
published Dr. Hau's description of
work in which she slowed light to
about 38 miles an hour in a system
involving beams of light shone
through a chilled sodium gas.
Dr. Walsworth and Dr. Lukin mentioned
Dr. Hau's new work in their
paper, saying she achieved her latest
results using a similarly chilled gas.
Dr. Lukin cited her earlier work, which
Dr. Hau produced in collaboration with
Dr. Stephen Harris of Stanford University, as the
inspiration for the new experiments.
Those experiments take the next step,
stopping the light's propagation completely.
"We've been able to hold it there and
just let it go, and what comes out is
the same as what we sent in," Dr. Walsworth
said. "So it's like a freeze frame."
Dr. Walsworth, Dr. Lukin and their team
slowed light in a gas form of
rubidium, an alkaline metal element.
The deceleration of the light in the rubidium
differed in several ways from
how light slows through an ordinary lens.
For one thing, the light dimmed
as it slowed through the rubidium.
Another change involved the behavior
of atoms in the gas, which
developed a sort of impression of
the slowing wave.
This impression, actually consisting of
patterns in a property of the atoms
called their spin, was a kind of record
of the light's passing and was
enough to allow the experimenters to
revive or reconstitute the original beam.
Both Dr. Hau's original experiments
on slowing light, and the new ones
on stopping it, rely on a complex
phenomenon in certain gases called
electromagnetically induced
transparency, or E.I.T.
This property allows certain gases, like
rubidium, that are normally
opaque to become transparent
when specially treated.
For example, rubidium would normally
absorb the dark red laser light
used by Dr. Walsworth and his colleagues,
because rubidium atoms are
easily excited by the frequency of that light.
But by shining a second laser, with a slightly
different frequency, through
the gas, the researchers rendered it transparent.
The reason is that the two lasers create
the sort of "beat frequency" that occurs when
two tuning forks simultaneously
sound slightly different notes.
The gas does not easily absorb that
frequency, so it allows the light to
pass through it; that is, the gas
becomes transparent.
But another property of the atoms, called
their spin, is still sensitive to the
new frequency. Atoms do not actually
spin but the property is a quantum-mechanical
effect analagous to a tiny bar magnet that can be
twisted by the light.
As the light passes through, it alters
those spins, in effect flipping them.
Though the gas remains transparent,
the interaction serves as a friction or
weight on the light, slowing it.
"This language makes it difficult
to avoid envisioning a wave writing
on the sand (from which impression
one would then "recreate" the wave)."
Using that technique, Dr. Hau and Dr. Harris
in the earlier experiment slowed light to
a crawl. But they could not stop it, because the
transparent "window" in the gas became
increasingly narrower, and more
difficult to pass through, as the light
moved slower and slower.
In a recent theoretical advance,
Dr. Lukin, with Dr. Suzanne Yelin of
Harvard-Smithsonian and Dr. Michael
Fleischhauer of the University of
Kaiserslautern in Germany, discovered
a way around this constraint.
They suggested waiting for the beam
to enter the gas container, then smoothly
reducing the intensity of the second beam.
The three physicists calculated that this
procedure would narrow the window, slowing
the first beam, but also "tune" the system so
that the beam always passes through.
The first beam, they theorized, should slow
to an infinitesimally slow speed, finally present
only as an imprint on the spins, with no visible light
remaining. Turning the second beam back on,
they speculated, should reconstitute the first beam.
The new experiments bore those ideas out.
"The light is actually brought to a stop
and stored completely in the atoms," Dr. Harris said.
"There's no other way to do that. It's been done
— done very convincingly, and beautifully."
The FBI
Washington AC
Sent via Deja.com
http://www.deja.com/
S D Rodrian
ste...@iea.com (Steve McGrew) wrote:
> On Fri, 19 Jan 2001 02:12:10 GMT, S D Rodent <the...@my-deja.com>
> wrote:
>
> > To quote S D Rodrian:
> > http://web.sdrodrian.com
> >
> > "... In reality what they did
> > was to "pressure" the photon
> > into such proximity with the
> > gas atoms that they were
> > captured gravitationally: This
> > is a way of saying that the atoms
> > (which are the ones that are really
> > "moving" at the speed of light (not
> > the photons) "grabbed" the photons
> > and dragged them along (which
> > speeding up of the photon to "our"
> > greater speed we naturally interpret
> > as "slowing down" to "our" state of
> > "motionlessness."
>
>
> Unfortunately, this is a prime example
> of pseudoscientific BS!
Much more unfortunate still is the fact that
without any understanding whatsoever of what
is being discussed (evidenced by the above critic's
inability to express/cite ANY proof/argument against
the position of the original statement--and ignoring
that gravity is the ONLY force in effect in the
universe, with the other "three forces" merely being
different quantitative/qualitative aspects of it)...
expert-witness-wanna-bes like the critic above intrude
upon all discussions merely to throw in a haughty: "No
it's not!" (Apparently hoping to get everybody mired
in one of their, "No it's not--Yes it is" theater of the
absurd fracas.
> Gravitation has absolutely nothing to do
> with the experiment or the
> observed effect.
No, of course not! It was carried out [sarcasm]
on another dimension altogether (one
completely devoid of gravitational effects
... naturally, by massless researchers).
> If you want to understand the experiments,
> read the original papers.
Sir: Read the article yourself (it's included in
the original post in its entirety, forGodsSakes).
> Don't believe *anything* you get from the Web or
> from a newsgroup.
> Steve
Well, your categorical rejection of one
rather common source of knowledge
suggests it may not be the only source (of
knowledge) you probably reject out-of-hand.
Perhaps the probability that you are not
confident enough of what you (think you) know
--of the truth-- makes you afraid that you'll
be blinded by any lie you cannot shine "your
truth" on. I cannot tell either way; but it
does very strongly suggest that IF you had known
what argument to make against it... you'd have
made it. You did not, instead choosing to just
cry out: "T'aint so!" And then running away
as fast as you could.
Look: On the outside chance that you do not
understand that gravity is all there is to our
universe... I would be most glad to inform you on
the evolution of the universe. This is not yet
taught in the classrooms of physics, because
the Beagle hath not yet brought back the monkeys
from the stars.
Kindly,
S D Rodrian
web.sdrodrian.com
sdrodrian.com
S D Rodrian
"tinytess" <tinyte...@yahoo.com.au> wrote:
> remotely interesting...but whats your point?
That the universe (reality) hath
a natural explanation. Does the matter
interest you further?
S D Rodrian
web.sdrodrian.com
sdrodrian.com
re:
> S D Rodent <the...@my-deja.com> wrote in message
> news:9487lo$c9t$1...@nnrp1.deja.com...
> > From The New York Times:
> > January 18, 2001
> >
> > Scientists Bring Light to Full Stop, Hold
> > It, Then Send It on Its Way
> >
> > By JAMES GLANZ
> >
> > Researchers say they have
> > slowed light to a dead stop,
> > stored it and then released it as if it
> > were an ordinary material particle.
> >
> > To quote S D Rodrian:
> > http://web.sdrodrian.com
> >
> > "... In reality what they did
> > was to "pressure" the photon
> > into such proximity with the
> > gas atoms that they were
> > captured gravitationally: This
> > is a way of saying that the atoms
> > (which are the ones that are really
> > "moving" at the speed of light (not
> > the photons) "grabbed" the photons
> > and dragged them along (which
> > speeding up of the photon to "our"
> > greater speed we naturally interpret
> > as "slowing down" to "our" state of
> > and three collaborators - Dr. David Phillips,
> > Annet Fleischhauer and Dr. Alois Mair, all at
> > Harvard-Smithsonian - is scheduled to appear
> > - done very convincingly, and beautifully."
> >
> >
> > The FBI
> > Washington AC
> >
> >
> >
> >