News & Highlights

Research Highlights

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...
Altered States
Published: 04-12-2009
Understanding how molecules collide is a hot topic in ultracold physics. Knowing the number of times molecules crash into each other and what happens when they do helps theorists predict the best ways to cool molecules to merely cold (1 K–1 mK), pretty cold (1 mK–1 µk), or ultracold ( Fellow John Bohn recently decided to investigate the general collision behavior of polar molecules in low-temperature gases. He wanted to see whether knowing the molecule’s dipole moment and mass would be...
It Takes Two to Tango
Published: 04-12-2009
Quantum dots are tiny structures made of semiconductor materials. With diameters of 1–5 nm, they are small enough to constrain their constituents in all three dimensions. This constraint means that when a photon of light knocks an electron into the conduction band and creates an electron/hole pair, the pair can’t get out of the dot. In terms of quantum mechanics, this confinement means that the wavelengths of the wave functions of both the electron and the hole are forced to be significantly...
How to Marry a Microscope
Published: 04-10-2009
The most important step for a microscope wanting to marry another microscope is finding the right partner. A professional matchmaker, such as the Perkins lab, might be just the ticket. The group recently presided over the nuptials of atomic force microscopy and optical-trapping microscopy. Research associate Gavin King, graduate students Ashley Carter and Allison Churnside, CU freshman Louisa Eberle, and Fellow Tom Perkins officiated. The marriage produced an ultrastable atomic force...
Fermions in Collision?
Published: 04-07-2009
According to the laws of quantum mechanics, identical fermions at very low temperatures can’t collide. These unfriendly subatomic particles, atoms, or molecules simply will not share the same piece of real estate with an identical twin. A few years back, researchers in the Ye lab considered this unneighborly behavior a big advantage in designing a new optical atomic clock based on an ensemble of identical 87Sr atoms. They (along with every other physicist in the world) assumed that using...
Collision Course
Published: 04-05-2009
The Greene group just figured out everything you theoretically might want to know about four fermions "crashing" into each other at low energies. Low energies in this context mean ultracold temperatures under conditions where large, floppy Feshbach molecules form. The group decided to investigate four fermions because this number makes up the smallest ultracold few-body system exhibiting behaviors characteristic of the transition between Bose-Einstein condensation and superfluidity. Senior...
Qubits in Action
Published: 04-05-2009
Fellows Ana Maria Rey and Jun Ye have come up with a clever idea that should make it much easier to design a quantum computer based on alkaline-earth atoms such as strontium (Sr). In this work, they collaborated with former research associate Marty Boyd, former JILA Fellow Peter Zoller (University of Innsbruck), and colleagues from Harvard University and the University of Innsbruck. To understand the new quantum computing idea, it’s helpful to imagine a high-tech company as a quantum...

Pages