News & Highlights

Research Highlights

The Quantum Control Room
Published: 03-21-2011
In 2008, the Ye and Jin groups succeeded in making ultracold potassium-rubidium (KRb) molecules in their ground state (See “Redefining Chemistry at JILA” in the Spring 2010 issue of JILA Light & Matter). Their next goal was to figure out how to precisely control chemical reactions of these ultracold polar molecules by manipulating the quantum states of the reactants. But first the researchers had to discover how to calm those reactions down enough to study them. Under the conditions in...
The Fickle Finger of Fate
Published: 02-24-2011
Putting the brakes on a superfluid dipolar Bose-Einstein condensate (BEC) just got a whole lot more interesting. Last year, the Bohn theory group explored what would occur in a dipolar BEC when a laser probe — think of it like a finger — tickled a BEC just hard enough to excite a roton. (see JILA Light & Matter, Summer 2010). The roton is a strange type of quasi particleformed when a number of strongly magnetic atoms or dipolar molecules come together and act like a different kind of...
Strontium Clock Performance Skyrockets
Published: 02-03-2011
Quantum Paradox Derails Unwanted Collisions In 2008-2009, much to their amazement,researchers working on the Jun Ye group’s neutral Sr optical atomic clock discovered tiny frequency shifts caused by colliding fermions! They figured out that the clock laser was interacting slightly differently with the Sr atoms inside a one-dimensional (pancake-shaped) trap. The light-atom interactions resulted in the atoms no longer being identical. And, once they were distinguishable, formerly unneighborly...
The Quantum Modeling Agency
Published: 01-14-2011
“Nature is built quantum mechanically,” says Fellow Jun Ye, who wants to understand the connections between atoms and molecules in complex systems such as liquids and solids (aka condensed matter). He says that the whole Universe is made of countless interacting particles, and it would be impossible to figure out the myriad connections between them one particle at a time, either theoretically or experimentally. Fortunately, in 1986 Richard Feynman envisioned a work-around for the challenge of...
Sharing the Adventure of Science
Published: 01-03-2011
Graduate students or research associates at JILA have the option of signing up to help teach after-school science classes to elementary and middle school students in the St. Vrain School District. The volunteers expect to stimulate the children to learn to think critically, enjoy science activities, and become confident in their own abilities to master difficult concepts. What they may not anticipate at first is that they will learn some important skills themselves, including the ability to...
Rainbows of Soft X-Rays
Published: 12-06-2010
The vision of a tabletop x-ray laser has taken a giant step into reality, thanks to Tenio Popmintchev, Ming-Chang Chen and their colleagues in the Kapteyn/Murnane group. By focusing a femtosecond laser into a gas, Popmintchev and Chen generated many colors of x-rays at once, in a band that stretched from the extreme ultraviolet into the soft x-ray region of the electromagnetic spectrum, spanning wavelengths of ranging from about 6 to 2.5 nm. This broad x-ray band has so many different colors...
Sayonara Demolition Man
Published: 11-30-2010
The secret for reducing quantum noise in a precision measurement of spins in a collection of a million atoms is simple: Pre-measure the quantum noise, then subtract it out at the end of the precision measurement. The catch is not to do anything that detects and measures the spins of individual atoms in the ensemble. If states of individual atoms are measured, then those atoms stop being in a superposition and the subsequent precision measurement will be ruined. So, whatever measurement...
Deciphering Nature's Fingerprints
Published: 11-24-2010
Fellow Jun Ye’s group has enhanced the molecular fingerprinting technique with the development of a mid-infrared (mid-IR) frequency comb.  The new rapid-detection technique can now identify traces of a wider variety of molecules found in mixtures of gases. It offers many advantages for chemical analysis of the atmosphere, climate science studies, and the detection of suspicious substances. In addition, planning is already underway for clinical trials of a noninvasive medical breath analyzer...
The Guiding Light
Published: 11-24-2010
Atomic force microscopy (AFM) just got a whole lot more efficient for studying proteins and other biomolecules. Graduate student Allison Churnside, former research associate Gavin King, and Fellow Tom Perkins recently used a laser to detect the position of sparsely distributed biomolecules on a glass cover slip. Since the same laser is also used to locate the AFM tip, it is now possible to align the microscope tip and sample with a precision of 40 nm, before the AFM tip even touches the...
Curling Up in a Nanobathtub
Published: 08-18-2010
In microscopic studies of single biological molecules or nanoparticles, it’s useful to be able to precisely control the temperature around the sample. Until now, heating has required electric currents that warm up microscope stages, slides, and optics in addition to the specimen under study. Such methods are slow and hard to control, not to mention capable of accidentally altering the chemistry or structure of the sample. Now there is a better solution for keeping samples nice and warm: The...
The Mysterious Fermi Gap
Published: 08-18-2010
In 2008, the Deborah Jin Group introduced a new technique, known as atom photoemission spectroscopy, to study a strongly interacting ultracold gas cloud of potassium (40K) atoms at the crossover point between Bose-Einstein condensation and superfl uidity via the pairing of fermionic atoms (See JILA Light & Matter, Summer 2008). Near the crossover point, the physics of superfl uidity in an atom gas system may be connected to that of high-temperature superconductivity. In the 2008 experiment...
An Occurence at the Solvent Bridge
Published: 08-18-2010
Solvents don’t just dissolve other chemicals (called solutes) and then sit around with their hands in their pockets. Instead, they get involved in all sorts of different ways when dissolved molecules toss electrons around, i.e., they facilitate charge transfer events. In research, the hard part is fi guring out exactly how and when solvent molecules get involved when an electron hops from one solute molecule to another. For example, in liquids (which do most of the dissolving), solvent...
Them's the Brakes
Published: 08-18-2010
The Bohn group has just come up with an exciting, really complicated experiment for someone else to do. This is something theorists like graduate student Ryan Wilson, former research associate Shai Ronen, and Fellow John Bohn get a kick out of. In this case, they’re recommending an experiment to measure how fast a tiny blue laser would have to move through a dipolar Bose-Einstein condensate (BEC) to create ripples. Energy lost to the ripples would create a drag force on the laser, signaling the...
Redefining Chemistry at JILA
Published: 05-06-2010
Fellows Deborah Jin, Jun Ye, and John Bohn are exploring new scientific territory in cold-molecule chemistry. Experimentalists Jin and Ye and their colleagues can now manipulate, observe, and control ultralow-temperature potassium-rubidium (KRb) molecules in their lowest quantum-mechanical state. Theorist Bohn analyzes what the experimentalists see and predicts molecule behaviors under different conditions. No other group in the world has even succeeded in making molecules like these, much...
Freeze Frame
Published: 04-17-2010
The cold-molecule collaboration has developed a method for directly imaging ultracold ground-state KRb molecules. Their old method required the transfer of ultracold KRb molecules into a Feshbach state, which is sensitive to electric and magnetic fields. Thus researchers had to turn off the electric field and keep the magnetic field at a fixed value during the imaging process. However, the team recently began to probe the influence of changing electric and magnetic fields on the behavior of...
Good Vibrations
Published: 04-03-2010
Mathias Weber and his team recently did the following experiment: They excited the methyl group (CH3) on one end of nitromethane anion (CH3NO2-) with an infrared (IR) laser. The laser got the methyl group vibrating with enough energy to get the nitro group (NO2) at the other end of the molecule wagging hard enough to spit out its extra electron. The figure here, which appeared on the April 1, 2010, cover of the Journal of Physical Chemistry A, shows an artist’s conception of the process from...
The BEC Transporter
Published: 04-02-2010
The Dana Z. Anderson group has developed a microchip-based system that not only rapidly produces Bose-Einstein condensates (BECs), but also is compact and transportable. The complete working system easily fits on an average-sized rolling cart. This technology opens the door to using ultracold matter in gravity sensors, atomic clocks, inertial sensors, as well as in electric- and magnetic-field sensing. Research associate Dan Farkas demonstrated the new system at the American Physical Society’s...
Nanomeasurement is a Matter of the Utmost Precision
Published: 03-06-2010
Not content with stepping on their bathroom scales each morning to watch the arrow spin round to find their weights, former research associate John Teufel and Fellow Konrad Lehnert decided to build a nifty system that could measure more diminutive forces of half an attoNewton (0.5 x 10-18 N). Their new system consists of a tiny oscillating mechanical wire embedded in a microwave cavity with an integrated microwave interferometer, two amplifiers (one of them virtually noiseless), and a signal...
Radical Changes
Published: 02-24-2010
Carl Lineberger and his group recently achieved some exciting firsts: (1) the experimental observation of the oxyallyl diradical, a key intermediate in a series of important chemical reactions, and (2) the posting of an abstract of the Angewandte Chemie cover story reporting this achievement — on Facebook! While the Lineberger group is responsible for the clever design of the photoelectron spectroscopy experiments that led to the observation of oxyallyl diradical, Lineberger was astonished...
Buried Treasure
Published: 10-01-2009
The Anderson and Cornell groups have adapted two statistical techniques used in astronomical data processing to the analysis of images of ultracold atom gases. Image analysis is necessary for obtaining quantitative information about the behavior of an ultracold gas under different experimental conditions. Until now, the preferred method has been to find a shape (such as a Gaussian) that looks like the results and write an image-fitting routine to probe a series of photographs. The drawback is...
Extreme "Sheep" Herding
Published: 07-30-2009
The new molecules are as big as a virus. They’re ultracold. And, they’re held together by a ghostly quantum mechanical force field with the energy of about 100 billionths of an electron volt. These strange diatomic rubidium (Rb) molecules are the world’s first long-range Rydberg molecules. They were recently formed in Tilman Pfau’s laboratory at the University of Stuttgart from an ultracold cloud of Rb atoms. One neat aspect of the new experiment is that in 2000, Fellow Chris Greene’s...
Rave Reviews for the Efimov Quartet
Published: 07-15-2009
The most peculiar and fragile "molecules" ever discovered are the weakly bound triatomic Efimov molecules that form under specific conditions in a Bose-Einstein condensate (BEC). JILA theorists have now shown that such molecules can interact with an additional atom to form "daughter" molecules, which inherit many of their mother’s characteristics. What's strange is that the atoms in a BEC mostly feel no force of attraction to each other. In fact, the atoms only feel attracted to one...
Holy Monodromy!
Published: 07-02-2009
Monodromy literally means "once around." The term is applied in mathematics to systems that run around a singularity. In these systems, a parameter that describes the state of the system changes when the system loops around the singularity. Since monodromy’s discovery in 1980, mathematicians have predicted that many physical systems have it, including pendulums and tops as well as atoms and molecules. Fellow Heather Lewandowski’s group recently decided to do an experiment to see whether a...
A Light Changing Experience
Published: 04-29-2009
The Weber group wants to understand how the individual building blocks of DNA interact with ultraviolet (UV) light. Such knowledge would be an important step toward gaining a detailed understanding of the molecular processes responsible for the UV-induced DNA damage that results in mutations and can lead to cancer or cell death. Graduate student Jesse Marcum, student assistant Amit Halevi, and Fellow J. Mathias Weber recently studied the UV photodissociation of DNA subunits, called...
Free Association Tunes
Published: 04-14-2009
Starting with ultracold atoms in a Bose-Einstein condensate, it’s possible to create coherent superpositions of atoms and molecules. Fellow Carl Wieman and others have done exactly this. Recently, the Jin group wondered if it would be possible to accomplish the same thing starting with a normal gas cloud of atoms. To spice up the experiment, they included two kinds of atoms: neighborly bosons (87Rb) that readily pile up in the same state and more independent-minded fermions (40K), no two of...

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