SCIENTISTS RESEARCHING A WAY TO BETTER USE SUPERCONDUCTING MATERIALS

FROM:  NATIONAL SCIENCE FOUNDATION 
Researcher studies unsolved problem of interacting objects
Insights could enable more widespread use of superconducting materials

One of science's biggest puzzles is figuring out how interacting objects behave collectively. Take water, for example. "It's a molecule, but it's also a liquid with specific properties," says Daniel Sheehy, an assistant professor of physics at Louisiana State University. "How does the liquid come from the microscopic action of these water molecules?"

Sheehy doesn't study water, but he likes to use it to describe what he does study, which is many-particle quantum mechanics, that is, how atoms organize themselves at very low temperatures when they become trapped in beams of laser light, and whether they reach a superfluid state, a phenomenon that occurs only when it is extremely cold.

In a superconductor, the electrons form a superfluid which "is like a liquid, but better," Sheehy says. "It never slows down and the electrical resistance is zero, meaning none of the energy is lost."

The down side, however, is that this requires very cold temperatures to achieve, on the order of 10 kelvins (minus 263 C, minus 442 F), for conventional superconductors, which is why they generally only are used in special applications, such as in MRI machines, where they are kept cold with liquid helium.

"This is why they are not used in power lines," he says. "You would need refrigerators, which isn't very practical."

Sheehy's goal is to gain further insights that could enable more widespread uses for superconducting materials. "Might it be possible to make material that is a superconductor at ambient temperatures?" he asks. "No one knows. It is a very difficult goal, a very big goal. But we would like to use superconductors in places where they are not used now."

He is performing theoretical calculations regarding clouds of extremely cold atoms--imagine very dilute particles of gases trapped in a laser field--to see how they behave and whether they show superconducting properties. "All I want to know is if I put a million atoms in a small region and watch them interact, what can they do?" he says.

He is examining the activities of different alkali gases--those in the first column of the Periodic Table--because "they have only one outermost electron, making them easier to control," he says. "First, let's understand the simplest system we can think of so we can develop the theory. Let's fundamentally understand nature and this unsolved problem of interacting objects."

He does not conduct actual physical experiments, but is a theorist "who uses a computer, as well as paper and pencil calculations," to determine the properties of these clouds of atoms. "I am interested in the superfluid states of these atoms, which is where the particles don't have any viscosity; they flow without resistance," he says.

Sheehy is conducting his research under a National Science Foundation (NSF) Faculty Early Career Development (CAREER) award, which he received in 2012. The award supports junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education, and the integration of education and research within the context of the mission of their organization. NSF is funding his work with $428,200 over five years.

The grant's educational component includes developing more interactive materials in large-size physics classes so that they go beyond the "lecture" format, "with more hands-on activities that get them thinking," he says. "We will be trying to use Internet applications with certain computer programs that demonstrate the principles of quantum mechanics. This, hopefully, will get them to better learn physics, and get them excited about a future in science."

He also plans an outreach project to the public, and to high school and middle school students, including an in-school demonstration program aimed at inspiring the interest of minority students in science, and in pursuing science careers.

"The field of cold atoms is growing rapidly, fueled by numerous recent experimental breakthroughs, making it an ideal area for students to work in," he says. "We're working on fundamental problems that are conceptually simple but yet still intellectually stimulating and experimentally relevant."

-- Marlene Cimons, National Science Foundation
Investigators
Daniel Sheehy
Related Institutions/Organizations
Louisiana State University & Agricultural and Mechanical College

SPACE BUCKYBALLS IN SOLID FORM FOUND BY NASA

The following excerpt is from the NASA website:

“NASA'S SPITZER FINDS SOLID BUCKYBALLS IN SPACE
WASHINGTON -- Astronomers using data from NASA's Spitzer Space
Telescope have, for the first time, discovered buckyballs in a solid
form in space. Prior to this discovery, the microscopic carbon
spheres had been found only in gas form.

Formally named buckminsterfullerene, buckyballs are named after their
resemblance to the late architect Buckminster Fuller's geodesic
domes. They are made up of 60 carbon molecules arranged into a hollow
sphere, like a soccer ball. Their unusual structure makes them ideal
candidates for electrical and chemical applications on Earth,
including superconducting materials, medicines, water purification
and armor.

In the latest discovery, scientists using Spitzer detected tiny specks
of matter, or particles, consisting of stacked buckyballs. They found
them around a pair of stars called "XX Ophiuchi," 6,500 light-years
from Earth.

"These buckyballs are stacked together to form a solid, like oranges
in a crate," said Nye Evans of Keele University in England, lead
author of a paper appearing in the Monthly Notices of the Royal
Astronomical Society. "The particles we detected are miniscule, far
smaller than the width of a hair, but each one would contain stacks
of millions of buckyballs."

Buckyballs were detected definitively in space for the first time by
Spitzer in 2010. Spitzer later identified the molecules in a host of
different cosmic environments. It even found them in staggering
quantities, the equivalent in mass to 15 Earth moons, in a nearby
galaxy called the Small Magellanic Cloud.

In all of those cases, the molecules were in the form of gas. The
recent discovery of buckyballs particles means that large quantities
of these molecules must be present in some stellar environments in
order to link up and form solid particles. The research team was able
to identify the solid form of buckyballs in the Spitzer data because
they emit light in a unique way that differs from the gaseous form.

"This exciting result suggests that buckyballs are even more
widespread in space than the earlier Spitzer results showed," said
Mike Werner, project scientist for Spitzer at NASA's Jet Propulsion
Laboratory in Pasadena, Calif. "They may be an important form of
carbon, an essential building block for life, throughout the cosmos."


Buckyballs have been found on Earth in various forms. They form as a
gas from burning candles and exist as solids in certain types of
rock, such as the mineral shungite found in Russia, and fulgurite, a
glassy rock from Colorado that forms when lightning strikes the
ground. In a test tube, the solids take on the form of dark, brown
"goo."

"The window Spitzer provides into the infrared universe has revealed
beautiful structure on a cosmic scale," said Bill Danchi, Spitzer
program scientist at NASA Headquarters in Washington. "In yet another
surprise discovery from the mission, we're lucky enough to see
elegant structure at one of the smallest scales, teaching us about
the internal architecture of existence."

NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., manages
the Spitzer Space Telescope mission for NASA's Science Mission
Directorate in Washington. Science operations are conducted at the
Spitzer Science Center at the California Institute of Technology in
Pasadena. Caltech manages JPL for NASA.”