Slashdot Mirror
Ultra-Dense Optical Storage on One Photon
Andreaskem submitted this story about researchers being able to encode an image into a photon and to later retrieve it intact. From the article: "It's analogous to the difference between snapping a picture with a single pixel and doing it with a camera — this is like a 6-megapixel camera... You can have a tremendous amount of information in a pulse of light, but normally if you try to buffer it, you can lose much of that information... We're showing it's possible to pull out an enormous amount of information with an extremely high signal-to-noise ratio even with very low light levels."
The Image is NOT encoded into one photon, at least not in a way that can be extracted again. Each individual photon is in a superposition of having gone all the possible paths and the set of those possible paths is the information to be extracted but when measured each photon will only reveal a small amount of information so it is only in the aggregate (by measuring lots of photons) that the initial image can be reproduced. At least this is what the article sounds like it is saying it wasn't very clear.
In fact it is probably best to think of this without quantum mechanics at all. What they did is pretty much like figuring out the shape of an object by shooting BBs at it and looking at which ones make it past the object.
The part that is supposedly new and interesting is the way they collected the photons at the other end. It didn't seem very clear on this but apparently by catching many of the photons in their device at one time it made it much easier to decode the image in the light.
If you liked this thought maybe you would find my blog nice too:
Both the poster's summary and the news release are incorrect. You cannot encode more information than quantum numbers on any quanta, it is not possible. I believe that another poster has a plausible explanation for what is actually going on: that they measure many photons and reconstruct the information by knowing the possible paths which do the encoding of information.
I suspect the original press release and the articles on Science Daily and PhysOrg are FUBAR. I think an article in the Washington Post is probably more accurate. Unfortunately the Phys. Rev. Letter web site doesn't seem to have the actual paper publicly available yet.
In about 1968, IBM had an optical memory where about 2 Km of optical path was folded into something the size of a filing cabinet using mirrors, and 1 bit was circulating endlessly. Optical fibres transparent enought to do this did not happen for years. This geta a brief mention in... http://www-03.ibm.com/ibm/history/history/year_196 8.html
MS Fnd in a Lbry
HAL DRAPER
From: Report of the Commander, Seventh Expeditionary Force,
Andromedan Paleoanthropological Mission
What puzzled our research teams was the suddenness of collapse
and the speed of reversion to barbarism, in this multigalactic
civilization of the biped race. Obvious causes like war, destruction,
plague, or invasion were speedily eliminated. Now the outlines of the
picture emerge, and the answer makes me apprehensive.
Part of the story is quite similar to ours, according to those who
know our own prehistory well.
On the mother planet there are early traces of *books*. This word
denotes paleoliterary records of knowledge in representational and
macroscopic form. Of course, these disappeared very early, perhaps
175,000 of our yukals ago, when their increase threatened to leave
no place on the planet's surface for anything else.
First they were reduced to *micros*, and then to *supermicros*,
which were read with the primeval electronic microscopes then extant.
But in another yukal the old problem was back, aggravated by colonization
on most of the other planets of the local Solar System, all of which were
producing *books* in torrents. At about this time, too, their cumbersome
alphabet was reduced to mainly consonantal elements (thus: thr cmbrsm alfbt
w rdsd t mnl cnsntl elmnts) but this was done to facilitate quick reading,
and only incidentally did it cut down the mass of Bx (the new spelling)
by a full third. A drop out of the bucket.
Next step was the elimination of the multitude of separate Bx
depositories in favor of a single building for the whole civilization.
Every home on every inhabited planet had a farraginous diffuser which
tuned in on any of the Bx at will. This cut the number to about one
millionth at a stroke, and the wise men of the species congratulated
themselves that the problem was solved.
This building, twenty-five miles square and two miles high, was buried
in one of the oceans to save land surface for parking space, and so our
etymological team is fairly sure that the archaic term liebury (Ibry) dates
from this period. Within no more than twenty-two yukals, story after story
had been added till it extended a hundred miles into the stratosphere.
At this level, cosmic radiation defarraginated the scanning diffusers,
and it was realized that another limit had been reached. Proposals were
made to extend the liebury laterally, but it was calculated that in three
yukals of expansion so much of the ocean would be thus displaced that the
level of the water would rise ten feet and flood the coastal cities.
Another scheme was worked out to burrow deeper into the ocean bottom,
until eventually the liebury would extend right through the planet like
a skewer through a shashlik (a provincial Plutonian delicacy), but it
was realized in time that this would be only a momentary palliative.
The fundamental advance, at least in principle, came when the
representational records were abandoned altogether in favor of *punched
supermicros*, in which the supermicroscopic elements were the punches
themselves. This began the epoch of abstract recs - or Rx, to use the
modern term.
The great breakthrough came when Mcglcdy finally invented mass-
produced *punched molecules* (of any substance). The mass of Rx
began shrinking instead of expanding. Then Gidbg proved what had
already been suspected; knowledge was not infinite, and the civilization
was asymptotically approaching its limits; the flood was leveling off.
The Rx storage problem was hit another body-blow two generations later
when Kwlsk used the Mcglcdy principle to develop the *notched electron*,
made available for use by the new retinogravitic activators. In the ensuing
ten yukals a series of triumphant developments wiped the problem out for
good, it seemed:
(1) Getting below matter level, Shmt began by notching quanta (an o
I just wondered if anyone noticed that this news story is exactly the same as the one /. posted under the heading, Slow Light = Fast Computing, on January 19?
Taking stuff apart since 1969 (TM)