| Topic: |
Religions > Atheism |
| User: |
"stoney" |
| Date: |
27 Jun 2005 03:20:01 AM |
| Object: |
MIT physicists create new form of matter |
http://web.mit.edu/newsoffice/2005/matter.html
MIT physicists create new form of matter
June 22, 2005
CAMBRIDGE, Mass. -- MIT scientists have brought a supercool end to a
heated race among physicists: They have become the first to create a
new type of matter, a gas of atoms that shows high-temperature
superfluidity.
Their work, to be reported in the June 23 issue of Nature, is closely
related to the superconductivity of electrons in metals. Observations
of superfluids may help solve lingering questions about
high-temperature superconductivity, which has widespread applications
for magnets, sensors and energy-efficient transport of electricity,
said Wolfgang Ketterle, a Nobel laureate who heads the MIT group and
who is the John D. MacArthur Professor of Physics as well as a
principal investigator in MIT's Research Laboratory of Electronics.
Seeing the superfluid gas so clearly is such a dramatic step that Dan
Kleppner, director of the MIT-Harvard Center for Ultracold Atoms,
said, "This is not a smoking gun for superfluidity. This is a cannon."
For several years, research groups around the world have been studying
cold gases of so-called fermionic atoms with the ultimate goal of
finding new forms of superfluidity. A superfluid gas can flow without
resistance. It can be clearly distinguished from a normal gas when it
is rotated. A normal gas rotates like an ordinary object, but a
superfluid can only rotate when it forms vortices similar to
mini-tornadoes. This gives a rotating superfluid the appearance of
Swiss cheese, where the holes are the cores of the mini-tornadoes.
"When we saw the first picture of the vortices appear on the computer
screen, it was simply breathtaking," said graduate student Martin
Zwierlein in recalling the evening of April 13, when the team first
saw the superfluid gas. For almost a year, the team had been working
on making magnetic fields and laser beams very round so the gas could
be set in rotation. "It was like sanding the bumps off of a wheel to
make it perfectly round," Zwierlein explained.
"In superfluids, as well as in superconductors, particles move in
lockstep. They form one big quantum-mechanical wave," explained
Ketterle. Such a movement allows superconductors to carry electrical
currents without resistance.
The MIT team was able to view these superfluid vortices at extremely
cold temperatures, when the fermionic gas was cooled to about 50
billionths of one kelvin, very close to absolute zero (-273 degrees C
or -459 degrees F). "It may sound strange to call superfluidity at 50
nanokelvin high-temperature superfluidity, but what matters is the
temperature normalized by the density of the particles," Ketterle
said. "We have now achieved by far the highest temperature ever."
Scaled up to the density of electrons in a metal, the superfluid
transition temperature in atomic gases would be higher than room
temperature.
Ketterle's team members were MIT graduate students Zwierlein, Andre
Schirotzek, and Christian Schunck, all of whom are members of the
Center for Ultracold Atoms, as well as former graduate student Jamil
Abo-Shaeer.
The team observed fermionic superfluidity in the lithium-6 isotope
comprising three protons, three neutrons and three electrons. Since
the total number of constituents is odd, lithium-6 is a fermion. Using
laser and evaporative cooling techniques, they cooled the gas close to
absolute zero. They then trapped the gas in the focus of an infrared
laser beam; the electric and magnetic fields of the infrared light
held the atoms in place. The last step was to spin a green laser beam
around the gas to set it into rotation. A shadow picture of the cloud
showed its superfluid behavior: The cloud was pierced by a regular
array of vortices, each about the same size.
The work is based on the MIT group's earlier creation of Bose-Einstein
condensates, a form of matter in which particles condense and act as
one big wave. Albert Einstein predicted this phenomenon in 1925.
Scientists later realized that Bose-Einstein condensation and
superfluidity are intimately related.
Bose-Einstein condensation of pairs of fermions that were bound
together loosely as molecules was observed in November 2003 by
independent teams at the University of Colorado at Boulder, the
University of Innsbruck in Austria and at MIT. However, observing
Bose-Einstein condensation is not the same as observing superfluidity.
Further studies were done by these groups and at the Ecole Normale
Superieure in Paris, Duke University and Rice University, but evidence
for superfluidity was ambiguous or indirect.
The superfluid Fermi gas created at MIT can also serve as an easily
controllable model system to study properties of much denser forms of
fermionic matter such as solid superconductors, neutron stars or the
quark-gluon plasma that existed in the early universe.
The MIT research was supported by the National Science Foundation, the
Office of Naval Research, NASA and the Army Research Office.
© 2005 MIT
--
Contempt of Congress meter reading-offscale.
Hello, theocracy with a fundamentalist US Supreme
Court who will ensure church and state are joined
at the hip like clergy and altar boys.
America 1776-Jan 2001 RIP
"As democracy is perfected, the office of president
represents, more and more closely, the inner soul
of the people. On some great and glorious day the
plain folks of the land will reach their heart's
desire at last and the White House will be adorned
by a downright moron." --- H.L. Mencken (1880 - 1956)
Religion is the original war crime.
-Michelle Malkin (Feb 26, 2005)
.
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| User: "Harry F. Leopold" |
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| Title: Re: MIT physicists create new form of matter |
27 Jun 2005 04:19:11 PM |
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On Sun, 26 Jun 2005 22:20:01 -0500, stoney wrote
(in article <ilrub114cfl87tb5ad2dk5td2vp0ujo9ml@4ax.com>):
http://web.mit.edu/newsoffice/2005/matter.html
MIT physicists create new form of matter
June 22, 2005
CAMBRIDGE, Mass. -- MIT scientists have brought a supercool end to a
heated race among physicists: They have become the first to create a
new type of matter, a gas of atoms that shows high-temperature
superfluidity.
Very Innteerristing! Thanks for posting this, Stoney.
--
Harry F. Leopold
aa #2076
AA/Vet #4
The Prints of Darkness
(remove gene to email)
łNo gods were physically harmed during the making of this post. However
nothing was in the contract about emotional or psychological harm.˛
.
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| User: "stoney" |
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| Title: Re: MIT physicists create new form of matter |
03 Jul 2005 05:08:06 PM |
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On Mon, 27 Jun 2005 11:19:11 -0500, Harry F. Leopold
<hleopold@coxyx.net> wrote:
On Sun, 26 Jun 2005 22:20:01 -0500, stoney wrote
(in article <ilrub114cfl87tb5ad2dk5td2vp0ujo9ml@4ax.com>):
http://web.mit.edu/newsoffice/2005/matter.html
MIT physicists create new form of matter
June 22, 2005
CAMBRIDGE, Mass. -- MIT scientists have brought a supercool end to a
heated race among physicists: They have become the first to create a
new type of matter, a gas of atoms that shows high-temperature
superfluidity.
Very Innteerristing! Thanks for posting this, Stoney.
Welcome.
--
Contempt of Congress meter reading-offscale.
Hello, theocracy with a fundamentalist US Supreme
Court who will ensure church and state are joined
at the hip like clergy and altar boys.
America 1776-Jan 2001 RIP
"As democracy is perfected, the office of president
represents, more and more closely, the inner soul
of the people. On some great and glorious day the
plain folks of the land will reach their heart's
desire at last and the White House will be adorned
by a downright moron." --- H.L. Mencken (1880 - 1956)
Religion is the original war crime.
-Michelle Malkin (Feb 26, 2005)
.
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