2. In our daily experience, most of us deal with three phases of matter : solid,
liquid and gas.
A fourth high energy phase of matter, plasma occurs in high energy
processes as near as a fire or as far away as the core of a star.
For decades, the existence of a fifth lower energy form of matter known as
Bose Einstein Condensate(BECs),was only a theoretical possibility.
In 2001, the Noble Prize for physics went to Eric Cornell, Wolfgang Ketterle,
and Carl Wieman, who used lasers,magnets,and evaporative cooling to
bring about this fascinating new phase of matter.
3. Bose-Einstein
condensate (BEC), a state
of matter which is formed by
cooling a gas of extremely
low density ,about one
hundred thousandth the
density of normal air ,to super
low temperatures . They can
slow light down to the
residential speed limit, flow
without friction . They are
effectively super atoms,
groups of atoms that behave
as one.
4. The theory of BECs was developed by Satyendra Nath Bose
and Albert Einstein in the early 1920s. Bose combined his
work in thermodynamics and statistical mechanics with the
quantum mechanical theories that were being developed,
and Einstein carried the work to its natural conclusions and
brought it to the public eye.At the time, none of the
necessary technology was available to make BECs in the
lab: cryonics were extremely limited, and the first laser wasn't
even built until 1960. The fine control allowed by modern
computers was also a prerequisite. Because of all of these
technological hurdles, it wasn't until 1995 that experimenters
were able to force rubidium atoms to form this type of
condensate.
FOUNDERS
5. Solids have the lowest energy levels (corresponding with
the lowest temperatures), while liquids and gases have
increasingly higher levels. At the top end of this scale, we
can add plasmas, which are energetic enough to emit
all kinds of energy in the form of heat and photons.
Bose-Einstein Condensates represent a fifth phase of
matter beyond solids. They are less energetic than solids.
We can also think of this as more organized than solids,
or as colder -- BECs occur in the fractional micro-Kelvin
range, less than millionths of a degree above absolute
zero; in contrast, the vacuum of interstellar space
averages a positively tropical 3 K.
BEC S AS COMPARED TO THE
OTHER STATES OF MATTER
6. BECs are more ordered than solids in that
their restrictions occur not on the
molecular level but on the atomic level.
Atoms in a solid are locked into roughly
the same location in regard to the other
atoms in the area.
Atoms in a BEC are locked into all of the
same attributes as each other; they are
literally indistinguishable, in the same
location and with the same attributes.
When a BEC is visible, each part that one
can see is the sum of portions of each
atom, all behaving in the same way,
rather than being the sum of atoms as in
the other phases of matter
7. Most research into Bose-Einstein Condensates serves as "basic"
research -- that is to say, it is more concerned with knowing more
about the world in general than with implementing a specific
technology. However, there are several potential uses for BECs.
The most promising application is in etching.
When BECs are fashioned into a beam, they are like a laser in their
coherence. That is to say, both a laser and a BEC beam run "in
lock step," guaranteeing that an experimenter can know how a
part of the beam will behave at every single location. This property
of lasers has been used in the past for etching purposes. A BEC
beam would have greater precision and energy than a laser
because even at their low kinetic energy state, the massive
particles would be more energetic than the massless photons.
PROPERTIES AND FUTURE APPLICATIONS
8. • The major technological concerns with a BEC beam
would be getting a clean enough environment for it to
function repeatedly and reducing the cost of BEC
creation enough to use BECs regularly in beams.
However, BEC beams or "atom lasers" could produce
precisely trimmed objects down to a very small scale --
possibly a nanotech scale. Their practical limits will be
found with experimentation
9. • One of the most commonly known properties of BECs is their
super fluidity. That is to say, BECs flow without interior friction.
• Since they're effectively super atoms, BECs are all moving in
the same way at the same time when they flow, and don't
have energy losses due to friction.
• Even the best lubricants currently available have some
frictional losses as their molecules interact with each other,
but BECs, while terribly expensive, would pose no such
problem.
10. • One of the problems physicists run into when teaching
quantum mechanics is that the principles are just
counter-intuitive.
• They're hard to visualize.
• But videos of BEC blobs several millimetres across show
wave-particle duality at a level we can comprehend
easily.
• We can watch something that acts like an atom, at a
size we could hold in our hands.
• MIT researchers have produced visible interference
fringe patterns from sodium BECs, demonstrating
quantum mechanics effects on the macro scale.
11. • Perhaps most interestingly, BECs have
been used to slow the speed of light to
a crawl -- from 186,282 miles per second
(3x108 m/s) in a vacuum to 38 miles per
hour (17 m/s) in a sodium BEC.
• No other substance so far has been
able to slow the speed of light within
orders of magnitude of that speed.
• Although so far this discovery has not
been applied to any technological
problems, researchers at Harvard
suggest that it might make possible
revolutions in communications, including
possibly a single-photon switch.
12. • The Bose-Einstein Condensate is to matter as the laser is to
light -- the analogy is precisely that simple.
• It took twenty years from the invention of the laser until its
technological applications began to take off.
• At first, lasers were considered too difficult to make to ever
find use in everyday applications; now, they're everywhere.
• The characteristics of BECs, specifically their response to
sound and other disturbances, are still under investigation,
but they hold the promise of many curious developments to
come.
