The Mudcat Café TM
Thread #59418 Message #1964015
Posted By: Amos
11-Feb-07 - 11:48 AM
Thread Name: BS: The Mother of all BS threads
Subject: RE: BS: The Mother of all BS threads
The quivering sanctimony ! The smug superiority!! The mind-boggling mythological pretensions!! The mind quivers with incipient nausea at the very thought!!
Think I don't know what I'm talking about? Chief Altar Boy, Saint Matthew's Episcopal Choice, right up to the time I realized...well, never mind what I realized. But it was pre-budding-bosom time, if ya take my meaning.
In other, much more important news, light is become muych more cooperative thanks to the lion-tamers over at Hahvahd Physics:
In 1999, Hau headed a team of scientists that slowed light, which
a brisk 186,282 miles a second when unimpeded, to a leisurely 38
hour by shining it into an exotic, ultracooled cloud of sodium atoms. At
temperatures a fraction of a degree above absolute zero, the atoms
coalesce into a single quantum mechanical entity known as a Bose-
condensate. Shining a laser on the cloud tunes its optical properties so
that it becomes molasses when a second light pulse enters it.
Then, in 2001, Hau and a second team of physicists, this one from the
Harvard-Smithsonian Center for Astrophysics, brought light to a complete
halt by slowly turning off the laser. The Bose-Einstein cloud turned
opaque, trapping the light pulse inside. When the laser was turned back
on, the trapped light pulse flew out.
The latest results add an additional twist: transporting the pulse to a
second Bose-Einstein cloud and regenerating the light there.
"That's the sort of stuff we find really sexy in this business," said
A. Cornell, a senior scientist at the National Institute of Standards
In the new Harvard experiment, when the initial pulse slammed into the
first Bose-Einstein cloud, the collision caused 50,000 to 100,000 of the
sodium atoms to start spinning, almost like small tops, and pushed this
small clump forward at less than a mile an hour.
Hau described the clump of atoms as a "metacopy" of the light pulse.
Although it consisted of sodium atoms instead of particles of light, it
exactly captured the characteristics of the light pulse.
The clump floated out from the rest of the cloud, traveled about
two-tenths of a millimeter and burrowed into a second Bose-Einstein
When a laser was shined on the second cloud, the atom clump transformed
into a new pulse of light identical to the original pulse.
It was refinements to the 2001 experimental technique that extended the
time the particles maintain quantum collective behavior. This allowed
clump to reach the second cloud.
Pondering the applications
Transforming a light signal into a clump of atoms could be a way of
storing information. ("You could put it on the shelf for a while," Hau
said.) It could also enable a way of performing calculations in future
optical computers that employ quantum algorithms to speed through
types of calculations.
But one hurdle to building a computer that calculates with light is that
it is difficult to grab onto and manipulate a quick-moving light pulse.
Performing calculations with atomic clumps would be much easier with the
result changed back into light and then sped to the next step.
"That has been a missing link," Hau said.
The advance could also find applications in quantum cryptography, which
can hide messages in codes that cannot be broken.
This idea of stamping atoms with the pattern of light, transporting them elsewhere and having the light pop out again is an interesting one. It could lead, sooner or later, to a genuine Cloak of Invisibility!! Wahey!!