MessageToEagle.com - Scientists will use new techniques to better understand chemistry and fundamental
physics and to obtain more precise measurements of time.
A team of scientists led by Tanya Zelevinsky, an assistant professor of physics of the
Columbia University in the City of New York created a new type of ultracold strontium molecule, made of pairs
of these glowing atoms.
Typically physicists couple lasers with magnetic fields to create ultracold molecules.
A glowing atom cloud, visible as blue light, in Tanya Zelevinsky's lab, cooled to nearly absolute zero or
minus 460 Fahrenheit. Image credit: Chris Osborn
However, Zelevinsky’s breakthrough was in revealing a method to produce large numbers of them in a fraction of a
second with just lasers, opening up the possibility of studying complex molecules resistant to magnetic forces.
Zelevinsky’s Pupin Hall lab is home to a sprawling contraption of gangly wires, metal pipes and chambers,
and flashing lights. Inside a container that opens up like a porthole is a glowing blue dot—a cloud of a million
atoms cooled to nearly absolute zero, or close to minus 460 degrees Fahrenheit, eight orders of magnitude below
room temperature.
“I can safely say this is the coldest point in New York City,” says Zelevinsky, an assistant
professor of physics who may know more about cold than most people—she was born in Siberia.
For most people, hot and cold are simply temperatures. But on a molecular level, the colder something is, the slower
the particles are moving. Absolute zero is the absence of thermal energy, the lowest theoretical temperature, colder
than any naturally occurring temperature in the universe.
“Many people think of lasers as heating things up because lasers carry a lot of energy, but you can also use lasers
to take away energy or to refrigerate matter,” explains Zelevinsky.
The discovery involved trapping the new molecules in a spider web-like laser scaffold, which allowed Zelevinsky to
measure the molecule’s spectral frequency at a very high resolution.
Some atoms have a unique frequency—a favorite wavelength of light or a color in the spectrum. Zelevinsky finely
tunes lasers to a shade slightly less energetic, or cooler, than the atom’s preferred frequency and shines it
on the atom.
Every time the atom absorbs a photon from the laser beam, it absorbs a little bit less energy than it wants to,
yet it still emits the same amount of energy as usual. In each cycle of absorption and emission it loses a little
bit of energy and thus becomes colder.
Zelevinsky’s cooling method is compounded by the Doppler effect, familiar to most of us as the phenomenon of a moving
ambulance whose siren sounds higher in pitch as it approaches and lower as it moves away.
Lasers have the same effect. When an atom moves toward a laser beam tuned to a lower energy than its preferred color,
it perceives the laser as the ideal shade due to the Doppler effect and is drawn to the beam that pushes it back and
ultimately stops it.
The cold temperature allows molecules to be trapped and observed, making them useful in metrology, the science of
measurement. One application is a molecule clock, a device that measures the vibration frequencies of a molecule
extremely precisely and thus is used to set time standards.
Zelevinsky’s technique could lead to a more exact measurement of the second. “The second will probably change, but
on an everyday scale we wouldn’t notice,” she says.
“One application of atomic and molecular clocks is checking whether certain properties of the universe have been constant since the big bang.”
Strontium molecules are good for building quantum clocks because the “time” they tell is not influenced by
hard-to-control things like heat in the lab or the Earth’s magnetic field.
“Columbia is the birthplace of modern atomic physics, started by Rabi in the 1930s,” she says. “We are excited
because ours is the first modern lab in atomic, molecular and optical physics here. Our technique expands the
scope of what you can do with molecules in the lab and the possibility for precise measurements in
fundamental physics,” Tanya Zelevinsky said.
Paper is published in the Sept. 13 issue of Physical Review Letters.
Teenage Girl Develops Cell Phone That Tests Your Heart
Catherine Wong is a 17-year-old high school student from New Jersey who she is already making a name for herself in both the science
and technology communities. Wong has developed a Bluetooth-enabled device that allows for remote cardiac examination.
No More Zoo Of Broken 3D Printed Objects -
A New Software Will Give Them Strength!
Objects created using 3-D printing have a common flaw: They are fragile and often fall apart or lose their shape.
"I have an entire zoo of broken 3-D printed objects in my office," said Bedrich Benes, an associate professor of computer graphics at Purdue University.
Become A Rocket Scientist And Space Cargo Pilot
With NASA's Free HIAD App!
Have you ever wanted to become a rocket scientist or space cargo pilot? How about mixing space science with a game?
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MessageToEagle.com - Scientists will use new techniques to better understand chemistry and fundamental
physics and to obtain more precise measurements of time.
All across the world there are people who love to stand outside and photograph the best our beautiful night sky has to offer.
Sometimes they can wait for hours just to take that one perfect shot! The results of these peoples' efforts...
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the concept of the time machine, from H.G. Wells to current sci-fi writers, and there are physicists who say we cannot rule out time travel.
Catherine Wong is a 17-year-old high school student from New Jersey who she is already making a name for herself in both the science
and technology communities. Wong has developed a Bluetooth-enabled device that allows for remote cardiac examination.
Objects created using 3-D printing have a common flaw: They are fragile and often fall apart or lose their shape.
"I have an entire zoo of broken 3-D printed objects in my office," said Bedrich Benes, an associate professor of computer graphics at Purdue University.
Have you ever wanted to become a rocket scientist or space cargo pilot? How about mixing space science with a game?
Want to try your hand at landing an inflatable spacecraft? All you need is a smart phone, a computer or a tablet.
