News & Highlights

Research Highlights

Explosive Evidence
Published: 02-27-2009
Imagine being able to study how molecules form on the quantum level. It turns out that researchers have already figured out some nifty techniques involving lasers and jets of reactive atoms for doing just that in a gaseous environment. Now graduate student Alex Zolot, former Visiting Fellow Paul Dagdikian of Johns Hopkins University, and Fellow David Nesbitt have taken this kind of study into a whole different arena: They recently probed the molecules that form when the surface of a liquid is...
Beams In Collision
Published: 02-20-2009
Last year the Ye group conducted an actual laboratory astrophysics experiment. Graduate students Brian Sawyer, Ben Stuhl, and Mark Yeo, research associate Dajun Wang, and Fellow Jun Ye fired cold hydroxyl (OH) radicals into a linear decelerator equipped with an array of highly charged electrodes and slowed the OH molecules to a standstill. These molecules were then loaded into a permanent magnetic trap where they became the stationary target for collision studies. Next, Sawyer and his...
Breaking Up Is Hard To Do
Published: 02-13-2009
An oxygen molecule (O2) doesn't fall apart so easily — even when an X-ray knocks out one of its electrons and superexcites the molecule during a process called photoionization. In this process, the X-ray first removes an electron from deep inside the molecule, leaving a hole in O2+. Then, an outer electron can fall into the hole, and a second outer electron gets ejected, carrying away any excess energy. The loss of the second electron is known as autoionization, or Auger decay. Surprisingly, in...
Fortune’s Bubbles Rise and Fall
Published: 02-08-2009
A while back, former graduate student Scott Papp, graduate student Juan Pino, and Fellow Carl Wieman decided to see what would happen as they changed the magnetic field around a mixture of two different rubidium (Rb) isotopes during Bose-Einstein condensation. They assumed that the interactions between the atoms would change. They also expected they would observe two distinct condensates at some point. What they didn’t expect was the formation of alternating "bubbles" of 85Rb and 87Rb inside...
Exotic Probes
Published: 10-13-2008
Xibin Zhou and his colleagues in the Kapteyn/Murnane group have come up with a clever new way to study the structure of carbon dioxide (CO2) and other molecules. The researchers use two innovative tools: (1) coherent electrons knocked out of the CO2 molecules by a laser and (2) the X-rays produced by these electrons when they recollide with the same molecules. The coherent electrons and X-rays are produced in a process known as high harmonic generation. The process involves four steps. First,...
The Oldest Trick in the Book
Published: 10-03-2008
The mission to find the electron electric dipole moment (eEDM) recently took a menacing turn. Chief Eric Cornell and his protégés were already hard at work characterizing the hafnium fluoride ion (HfF+). Their goal was to be the first in the world to complete the mission. In their choice of molecule, they owed a lot to JILA theorists Ed Meyer and John Bohn (a.k.a. Agents 13 and 86), who had taken the theory world by storm in 2006 when they devised a simple and straightforward method for the...
All Quiet on the Amplifier Front
Published: 10-01-2008
Fellow Konrad Lehnert needed a virtually noiseless amplifier to help with his experiments on nanoscale structures, so he invented one. Working with graduate student Manuel Castellanos-Beltran and NIST scientists Kent Irwin, Gene Hilton, and Leila Vale, he conceived a tunable device that operates in frequencies ranging from 4 to 8 GHz. This device has the lowest system noise ever measured for an amplifier. In fact, it produces 80 times less noise than the best commercial amplifier. More...
From Mental to Experimental?
Published: 07-16-2008
The John Bohn lab at JILA owes its very existence to a 2002 decision by the Colorado Rockies to begin storing baseballs in a room with ~50% humidity. The conventional wisdom at the time was that Denver’s thinner air was responsible for making Coors Field a hitter’s heaven. In mile-high Denver, hitters averaged two more home runs per game because the thinner air caused a given home run ball to travel 20 feet further than at sea level. The humidified baseballs were supposed to solve the problem...
Missing Link
Published: 07-10-2008
The Jin group recently came up with the first strong experimental link between superfluidity in ultracold Fermi gases and superconductivity in metals. What’s more, this feat was accomplished with photoemission spectroscopy, a tried-and-true technique that has been used for more than 100 years to study solids. This technique has been instrumental in revealing the properties of superconductors. It is just beginning to be developed in ultracold Fermi gases, where it could prove to be just as...
Bragging Rites
Published: 07-10-2008
What happens to a Bose-Einstein condensate (BEC) when its atoms interact strongly? One possibility for large attractive interactions is that the condensate shrinks and then explodes, as the Cornell and Wieman groups discovered in 2001. Another possibility for large repulsive interactions is behavior analogous to that of superfluid liquid helium. If superfluid liquid heliumlike dynamics could be observed and probed in strongly interacting atomic BECs, it would help bridge the gap between the...
Stalking the X-Ray Frequency Comb
Published: 07-09-2008
Fellow Jun Ye’s group is methodically working its way toward the creation of an X-Ray frequency comb. Recently, senior research associate Thomas Schibli, graduate student Dylan Yost, Fellow Jun Ye, and colleagues from IMRA America, Inc. developed a high-performance, ultrastable fiber laser optical frequency comb. At the same time, Yost developed a clever method for getting coherent short-wavelength light out of a femtosecond enhancement cavity used with the fiber laser. These achievements have...
Splash 2
Published: 07-07-2008
For many years, chemists have explored the differences between liquids and solids. One difference is that liquid surfaces tend to be softer than solid surfaces (from the perspective of molecules crashing onto them). Another difference is that the surface of at least one oily liquid (perfluorinated polyether, or PFPE) actually gets stickier as it gets hotter, according to a new study by graduate student Brad Perkins and Fellow David Nesbitt. This behavior contrasts with solid surfaces, which...
The Gravity of the Situation
Published: 04-10-2008
  What sort of experiment could detect the effects of quantum gravity, if it exists? Theories that go beyond the Standard Model of physics include a concept that links quantum interactions with gravity. Physicists would very much like to find evidence of this coupling as these two branches of physics are not yet unified in a single theory that explains everything about our world. Many physicists believe it would be very difficult to detect connections between quantum mechanics and...
Clock Talk
Published: 04-10-2008
By late 2006, Fellow Jun Ye’s clock team had raised the accuracy of its strontium (Sr)-lattice atomic clock to be just shy of that of the nation’s primary time and frequency standard, the NIST-F1 cesium (Cs) fountain clock. Graduate students Marty Boyd and Andrew Ludlow led the effort to improve the clock’s accuracy. But then, the clock team had to spend another year proving that its imporved clock would neither gain nor lose a second in more than 200 million years — thus surpassing the NIST-F1...
Every Breath You Take
Published: 04-02-2008
With every breath you take, you breathe out carbon dioxide and roughly 1000 other different molecules. Some of these can signal the early onset of such diseases as asthma, cystic fibrosis, or cancer. Thanks to graduate student Mike Thorpe and his colleagues in Fellow Jun Ye’s group, medical practitioners may one day be able to identify these disease markers with a low-cost, noninvasive breath test. The new laser-based breath test is an offshoot of Thorpe’s research on cavity-enhanced direct...
Lights, Magnets, Action!
Published: 02-18-2008
When the Jin and Ye group collaboration wanted to investigate the creation of stable ultracold polar molecules, the researchers initially decided to make ultracold KRb (potassium-rubidium) molecules and then study their collision behavior. Making the molecules required a cloud of incredibly cold K and Rb atoms, the ability to apply a magnetic field of just the right strength to induce a powerful attraction between the different kinds of atoms, and some low-frequency photons. The researchers...
One Ring to Rule Them All
Published: 02-12-2008
Benzene has a special ring structure that allows some of its electrons to be shared among all six carbon atoms in the ring. It turns out that chemists like Fellow J. Mathias Weber can adjust the charge density in the ring by exchanging hydrogen (H) atoms in the ring with other atoms or groups of atoms. Such exchanges can change the charge pattern in the ring "seen" by neighboring molecules. The interaction based on the charge distribution isn’t the whole story, however. Often, negatively...
DNA: Force of Nature
Published: 02-07-2008
The Perkins group is helping to develop DNA as a force standard for the nano world. Polymers of DNA act like springs, and DNA's elasticity may one day provide a force standard from 0.1–10 piconewtons (pN). One pN is the force exerted when 1 mW of light reflects off a mirror or the approximate weight of one hundred E. coli cells. DNA is an excellent candidate for a force standard because its double helix is reproduced with exquisite fidelity, which allows researchers (or cells) to build it...
Bohr + Schrödinger = Students Win
Published: 01-10-2008
A solid understanding of the structure and behavior of atoms is important for understanding the physical world, from the basic building blocks of nature to the inner workings of modern technology. However, education researchers have expressed different opinions regarding the best way to teach students the ins and outs of atoms. In particular, some have even recommended doing away with teaching the older and simpler Bohr model, asserting that it inhibits students’ ability to understand the...
Reflection Grisms
Published: 10-01-2007
Fellows Ralph Jimenez and Henry Kapteyn and their groups recently helped develop optical technology that will make femtosecond laser experiments much simpler to perform, opening the door to using such lasers in many more laboratories. The technology, which employs reflection grisms as laser pulse compressors, has been patented and is now available commercially. A reflection grism consists of metal reflection grating mounted on one face of a prism. Properly designed, they can compensate for...
Echoes of Hidden Worlds
Published: 10-01-2007
In Fellow Steve Cundiff’s lab, echoes of light are illuminating the quantum world. Former Graduate Student Gina Lorenz used a technique known as echo peak shift spectroscopy to probe the interactions of potassium atoms in a dense vapor. Research Associate Sam Carter then used the same method to investigate the interactions of excitons confined in two-dimensional semiconductor quantum wells. In semiconductors, an exciton forms when light promotes an electron from the valence band to the...
A Failure to Communicate
Published: 06-15-2007
In the quantum world inside Fellow Eric Cornell’s lab, communication occurs across a two-dimensional lattice array of Bose-Einstein condensates (BECs) when atoms tunnel out of superatoms (made from about 7000 garden-variety rubidium (Rb) atoms) into neighboring BECs. This communication keeps the array coherent, i.e., the phases of all condensates remain locked to each other. But something interesting happens when the tiny superatoms stop communicating among themselves. Vortices form. And how...
The Second Wave
Published: 04-12-2007
A second wave has appeared on the horizon of ultracold atom research. Known as the p-wave, it is opening the door to probing rich new physics, including unexplored quantum phase transitions. The first wave of ultracold atom research focused on s-wave pairing between atoms, where the “s” meant the resultant molecules are not rotating. In contrast, p-waves involve higher-order pairing where the atoms do rotate around each other. p-wave studies promise to expand and enhance the understanding of...
Exploring a Cold New World
Published: 04-12-2007
Researchers from the Ye, Bohn, and Greene groups are busy exploring a cold new world crawling with polar hydroxyl radical (OH) molecules. The JILA experimentalists have already discovered how to cool OH to “lukewarm” temperatures of 30 mK. They’ve precisely measured four OH transition frequencies that will help physicists determine whether the fine structure constant has changed in the past 10 billion years.1 In a recent and productive collaboration between JILA experimentalists and theorists...
Deep Sea Diving
Published: 04-10-2007
A Fermi sea forms at ultracold temperatures when fermions in a dilute gas stack up in the lowest possible energy states, with two fermions in each state, one spin up and one spin down. New analytic techniques for diving headfirst into the fundamental physics of this exotic form of matter were recently developed by graduate students Seth Rittenhouse and Javier von Stecher, Fellow Chris Greene, and former postdoc Mike Cavagnero, now at the University of Kentucky. Seth got the ball rolling (so to...

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