Research Highlights

  • Free Association Tunes
    April 14, 2009
    PI(s): Deborah Jin
    Topic(s): Atomic & Molecular Physics

    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.

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  • It Takes Two to Tango
    April 12, 2009
    PI(s): David Nesbitt
    Topic(s): Biophysics, Chemical Physics, Nanoscience

    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.

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  • Altered States
    April 12, 2009
    PI(s): John Bohn
    Topic(s): Atomic & Molecular Physics

    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 (< 1 µK) temperatures.

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  • Meet the JILA MONSTRs
    April 10, 2009
    PI(s): Steven Cundiff, Ralph Jimenez
    Topic(s): Laser Physics

    Fellows Steve Cundiff and Ralph Jimenez have created two precision optics instruments with a priceless potential for shedding light on condensed-matter and biological physics. Instrument shop staffer Kim Hagen aided and abetted them in their endeavor by creating exquisite CAD drawings and machining precision parts.

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  • How to Marry a Microscope
    April 10, 2009
    PI(s): Thomas Perkins
    Topic(s): Biophysics, Nanoscience

    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 microscope (AFM) capable of precisely studying proteins in real-world (ambient) conditions.

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  • A Quantum Leap for Precision Lasers
    April 09, 2009
    PI(s): Murray Holland, Jun Ye
    Topic(s): Laser Physics

    To be the best they can be, optical atomic clocks need better clock lasers — lasers that remain phase coherent a hundred times longer than the very best conventional lasers. For instance, light from the clock laser in Fellow Jun Ye’s lab can travel around the Earth 10 times before it loses coherence. However, realizing the potential of the lab’s optical clock requires that the laser light remain coherent for 1000 trips around the Earth. The brute force solution to this problem would be to operate the clock laser at 4 K. This approach would increase the cost, complexity, and size of the optical clock as well as rendering it impractical for space exploration and travel.

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  • The Gas Menagerie
    April 09, 2009
    PI(s): W. Carl Lineberger
    Topic(s): Chemical Physics

    Solvents — those things like water that dissolve other things like salt or sugar — are key players in some chemical reactions. That’s why the Lineberger group has come up with a nifty, but simplified, model system for studying solvent behavior. The group investigates the photodissociation and recombination of simple gas-phase anions, such as iodine bromide (IBr-), when they are surrounded by different numbers of carbon dioxide (CO2) solvent molecules.

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  • Collision Course
    April 05, 2009
    PI(s): Chris Greene
    Topic(s): Atomic & Molecular Physics, Chemical Physics

    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. 

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  • Qubits in Action
    April 05, 2009
    PI(s): Ana Maria Rey
    Topic(s): Quantum Information Science & Technology

    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.

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  • Explosive Evidence
    February 27, 2009
    PI(s): David Nesbitt
    Topic(s): Biophysics, Chemical Physics, Nanoscience

    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 bombarded with a very reactive gas.

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  • Beams In Collision
    February 20, 2009
    PI(s): Jun Ye
    Topic(s): Nanoscience, Precision Measurement

    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 colleagues aimed supersonic beams of either helium (He) atoms or deuterium molecules (D2) at the OH molecules. They then studied the resulting low-energy collisions, which took place at temperatures of 80–300 K.

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  • Threads of Stars and Shadow
    February 15, 2009
    PI(s): Andrew Hamilton
    Topic(s): Astrophysics

    The "dark ages" of the early Universe drew to a close with the appearance of enough stars to strip electrons off most of the hydrogen atoms in the gas clouds between galaxies. By a billion years after the Big Bang, these reionized atoms had rendered the Universe transparent to light. About 12.7 billion years later, visiting JILA member Gayler Harford, Fellow Andrew Hamilton, and Nickolay Gnedin of the Kavli Institute for Cosmological Physics decided to investigate the structures formed by ordinary matter (baryons) and dark matter soon after the reionization process was complete.

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  • Breaking Up Is Hard To Do
    February 13, 2009
    PI(s): Henry Kapteyn, Margaret Murnane
    Topic(s): Laser Physics, Nanoscience

    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.

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  • Spare Time
    February 10, 2009
    PI(s): Judah Levine
    Topic(s): Precision Measurement

    In a rural northern Colorado landscape punctuated by plentiful corn fields, a tree farm, an abandoned feedlot, and a handful of McMansions, only one thing is certain: the exact time. The nation’s backup time scale, consisting of four atomic clocks, two measurement systems, and supporting hardware is tucked away inside radio station WWV's remote transmission station, located 12 miles northwest of Fort Collins. Fellow Judah Levine travels to the station site an average of once a week to check on the performance of the backup time scale, which he designed and built in 2005.

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  • The Lab with the X-ray Eyes
    February 02, 2009
    PI(s): Henry Kapteyn, Margaret Murnane
    Topic(s): Laser Physics

    Researchers in the Kapteyn/Murnane group have decided to use soft X-ray bursts to watch the interplay of electronic and atomic motions inside a molecule. Such information determines how chemical bonds are formed or broken during chemical reactions.

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  • Exotic Probes
    October 13, 2008
    PI(s): Henry Kapteyn, Margaret Murnane
    Topic(s): Laser Physics, Nanoscience

    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 re-collide with the same molecules. The coherent electrons and X-rays are produced in a process known as high harmonic generation.

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  • The Oldest Trick in the Book
    October 03, 2008
    PI(s): Eric Cornell, John Bohn
    Topic(s): Atomic & Molecular Physics

    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 evaluation of molecular candidates for an eEDM search.

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  • Dusty Spaces
    October 02, 2008
    PI(s): Rosalba Perna
    Topic(s): Astrophysics

    Until recently, astronomers have had difficulty figuring out the composition and size of dust grains in galaxies beyond the Milky Way. They've had some luck with the Large and Small Magellanic Clouds (LMC and SMC, respectively). However, these two "satellite" galaxies are practically our next-door neighbors and much easier to observe.

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  • All Quiet on the Amplifier Front
    October 01, 2008
    PI(s): Konrad Lehnert
    Topic(s): Nanoscience, Precision Measurement

    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 importantly, it adds no noise to a measurement system — a critical feature for a system probing the quantum limits of measurement.

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  • Marriage — Galaxy Style
    October 01, 2008
    PI(s): Mitch Begelman, Phil Armitage
    Topic(s): Astrophysics

    Astrophysicists know that the centers of galaxies have supermassive black holes whose size correlates with the size of the galaxy surrounding them. They’ve also observed that galaxies collide and merge. In fact, galactic mergers were even more common billions of years ago in the Universe when today’s galaxies were still being assembled.

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  • The Polar Molecule Express
    September 30, 2008
    PI(s): Deborah Jin
    Topic(s): Atomic & Molecular Physics, Nanoscience

    The Jin and Ye groups recently crafted an entirely new form of matter — tens of thousands of ultracold polar molecules in their lowest energy state. The ground-state molecules are too cold to exist naturally anywhere in the Universe. But, like the Bose-Einstein condensates discovered in the mid-1990s, they promise to open the door to unprecedented explorations of the quantum world, including quantum information processing and exquisite precision measurement. That these molecules exist at all is a testament to the clever ideas and persistence of the Jin and Ye groups.

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  • From Mental to Experimental?
    July 16, 2008
    PI(s): John Bohn
    Topic(s): Atomic & Molecular Physics

    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. 

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  • Missing Link
    July 11, 2008
    PI(s): Deborah Jin
    Topic(s): Atomic & Molecular Physics, Nanoscience

    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 useful.

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  • Where Have All the Hot Planets Gone?
    July 11, 2008
    PI(s): Phil Armitage
    Topic(s): Astrophysics

    Like people, planets can migrate far from where they were born. In the case of planets, they usually travel toward their parent star, but some may also move away. Some wind up in blistering proximity to their Sun-like parents, orbiting them in 1.2 to 8 days. Such orbits are well inside the magnetic-field-induced cavities that typically separate such stars from their planet-forming accretion disks. There’s no way planets could have formed in these cavities, given their lack of raw materials for planet building and incredibly high temperatures.

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  • Bragging Rites
    July 10, 2008
    PI(s): Carl Wieman, Deborah Jin, Eric Cornell
    Topic(s): Atomic & Molecular Physics, Nanoscience

    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.

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  • Nanoartisans Search for Quantum Tremors
    July 10, 2008
    PI(s): Konrad Lehnert
    Topic(s): Nanoscience, Precision Measurement

    Nanoartisans Cindy Regal, John Teufel, and Konrad Lehnert have come up with a clever new way to observe ordinary (very small) things behaving quantum mechanically. They’ve tucked a nanomechanical beam (which is actually a really thin aluminum wire) inside a tiny resonant microwave cavity made of lightweight superconducting aluminum. This design ensures that very small forces will cause large detectable motion.

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  • Stalking the X-Ray Frequency Comb
    July 09, 2008
    PI(s): Jun Ye
    Topic(s): Laser Physics, Nanoscience, Precision Measurement

    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 opened the door to the generation of frequency combs in the extreme ultraviolet (EUV) and soft X-ray regions of the electromagnetic spectrum.

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  • Creating a Monster
    July 09, 2008
    PI(s): Andrew Hamilton
    Topic(s): Astrophysics

    Graduate student Robyn Levine, Fellow Andrew Hamilton, and colleagues from the University of Chicago’s Kavli Institute for Cosmological Physics are working on modeling how supermassive black holes grow inside galaxies.

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  • Splash 2
    July 07, 2008
    PI(s): David Nesbitt
    Topic(s): Biophysics, Chemical Physics, Nanoscience

    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 usually get stickier when they get colder!

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  • Water Music on the Radio
    April 14, 2008
    PI(s): Phil Armitage
    Topic(s): Astrophysics

    Fellow Phil Armitage is excited about the discovery of several new galaxies in which a disk of water masers is orbiting within half a light year of the central massive black hole. Like their counterpart M106 (NGC 4258) discovered in 1995, these hot (600 K) water molecules mase, i.e., emit coherent radio wavelength photons when they return to lower energy states after being excited by collisions inside the gas near the black hole. The water masers orbit black holes much like a planetary system, beaming their steamy songs toward radio telescopes on Earth.

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  • Clock Talk
    April 10, 2008
    PI(s): Jun Ye
    Topic(s): Laser Physics, Nanoscience, Precision Measurement

    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.

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  • The Gravity of the Situation
    April 10, 2008
    PI(s): Jun Ye
    Topic(s): Precision Measurement

    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.

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  • Every Breath You Take
    April 02, 2008
    PI(s): Jun Ye
    Topic(s): Laser Physics, Nanoscience, Precision Measurement

    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 optical frequency comb spectroscopy, a molecular fingerprinting technique reported in Science two years ago.

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  • Lights, Magnets, Action!
    February 18, 2008
    PI(s): Carl Wieman, Deborah Jin, Jun Ye
    Topic(s): Atomic & Molecular Physics

    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.

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  • Twinkle, Twinkle Mighty Quasar
    February 17, 2008
    PI(s): Jeffrey Linsky
    Topic(s): Astrophysics

    What did Fellow Jeff Linsky come home with from a 2006 SINS conference? He arrived at JILA with the realization that quasars twinkle for much the same reason stars twinkle: Light from both quasars and stars pass through turbulence that mixes up the light rays, causing the light to vary in intensity, or twinkle. However, the stars we see every night twinkle because of turbulence in the Earth’s dynamic atmosphere, which changes hundreds of times a second.

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  • Born to Spin
    February 14, 2008
    PI(s): Rosalba Perna
    Topic(s): Astrophysics

    Neutron stars are born in supernovae, spinning very fast. How fast they spin at birth depends on a variety of factors including the initial rotation of the star that goes supernova and what takes place during the supernova explosion. So, if you want to understand these phenomena, one place to start is by investigating how fast a new neutron star can initially spin.

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  • One Ring to Rule Them All
    February 12, 2008
    PI(s): J. Mathias Weber
    Topic(s): Chemical Physics

    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.

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  • A Microscope without a Lens
    February 11, 2008
    PI(s): Henry Kapteyn, Margaret Murnane
    Topic(s): Atomic & Molecular Physics

    The Kapteyn/Murnane group recently proved that you don’t need an accelerator facility to make the X-Rays for an X-Ray microscope. In fact, you can build the whole device on an optical bench — if you use a femtosecond laser to generate coherent X-Rays. The group makes coherent X-Rays by shining the laser into a glass tube filled with argon gas. The argon atoms absorb many low-energy laser photons and spit out high-energy X-Ray photons when they give up the absorbed energy. The X-Ray beam has all the desirable properties of laser light. For example, it does not spread rapidly and can be used to make holograms.

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  • Shocking Prediction Confirmed
    February 10, 2008
    PI(s): Andrew Hamilton
    Topic(s): Astrophysics

    Fellow Andrew Hamilton recently confirmed a prediction he made 10 years ago of the location of a reverse shock wave slowing the expansion of the debris from a supernova that occurred in 1006 AD. SN1006 was (and still is) the brightest supernova observed in recorded history; it was visible from Earth (without telescopes) for three years.

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  • DNA: Force of Nature
    February 07, 2008
    PI(s): Thomas Perkins
    Topic(s): Biophysics, Nanoscience

    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 with atomic precision.

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  • Something Massive This Way Comes
    February 03, 2008
    PI(s):
    Topic(s): Astrophysics

    In Ray Bradbury’s book Something Wicked This Way Comes, people get older or younger depending on which direction they ride on a carnival carousel. Something similar may happen to black holes, except that they become gargantuan or just a smidgeon larger depending on how fast they spin while they’re sucking in matter. The slower they spin, the faster they expand, says Visiting Fellow Andrew King of the University of Leicester. And, how fast they spin is influenced by the direction and orientation of clouds of gas being pulled into them. For the clouds, it’s a lot like jumping onto a carousel.

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  • A Protein Runs Through It
    February 01, 2008
    PI(s): Ralph Jimenez
    Topic(s): Biophysics, Chemical Physics

    An excellent way to watch proteins fold is to probe the inside of a microfluidics device with light. This tiny device contains micron-sized three-dimensional (3D) transparent channels that carry small amounts of liquid. Inside the channels, the fluid flow is laminar, i.e., there is no turbulence. Consequently, fluid flow through them is predictable and easily modeled. Microfluidics devices have been used to study chemical reaction kinetics and control chemical and biological reactions.

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  • Bohr + Schrödinger = Students Win
    January 10, 2008
    PI(s): Carl Wieman
    Topic(s): Atomic & Molecular Physics

    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 quantum nature of electrons in atoms.

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  • Discovering New Planets
    October 01, 2007
    PI(s): Richard McCray
    Topic(s):

    In JILA Fellow Dick McCray’s view, the way students learn astronomy is nearly the reverse of the way early astronomers learned astronomy. For instance, students might first learn Newton’s law of gravity and Kepler’s laws of planetary motion and then complete exercises in which they calculate what scientists have observed. But that’s not how Kepler did it. He fit observations of planetary motion with a controversial mathematical model that was much later confirmed to be correct by Newton’s theory of gravity.

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  • Reflection Grisms
    October 01, 2007
    PI(s): Ralph Jimenez
    Topic(s): Biophysics

    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.

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  • Echoes of Hidden Worlds
    October 01, 2007
    PI(s): Steven Cundiff
    Topic(s): Laser Physics

    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.

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  • X-Ray Demolition Derby
    September 30, 2007
    PI(s): Henry Kapteyn, Margaret Murnane
    Topic(s): Atomic & Molecular Physics

    X-rays are notorious for damaging molecules, including those in our bodies. High in the upper atmosphere, X-rays from the Sun break apart simple molecules like nitrogen (N2) and drive chemical reactions affecting the Earth. For these reasons, it’s important to understand exactly how radiation interacts with, damages, or destroys specific chemicals.

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  • A Failure to Communicate
    June 26, 2007
    PI(s): Eric Cornell
    Topic(s): Atomic & Molecular Physics

    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 many appear depends on temperature.

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  • X-Ray Vision
    May 01, 2007
    PI(s): Henry Kapteyn, Margaret Murnane
    Topic(s): Atomic & Molecular Physics

    It’s easy to make X-rays. Physicians and dentists make them routinely in their offices with a Roentgen X-ray tube, which emits X-rays every which way — just like a light bulb, which is nothing like a laser.

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  • Necklaces of Fire
    April 27, 2007
    PI(s): Mitch Begelman, Phil Armitage
    Topic(s): Astrophysics

    Two egg-shaped necklaces of magnificent stars orbit the enormous black hole known as Sagittarius A* (Sgr A*) at the center of the Milky Way Galaxy. Sgr A* (shown right) has long been thought to be well past promoting new star formation; until the necklaces were discovered, the black hole was considered to be just an aging, depleted relic of its glory days of organizing the Galaxy.

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  • Flash of Insight
    April 16, 2007
    PI(s): Rosalba Perna
    Topic(s): Astrophysics

    There’s a new aspect to research on gamma-ray bursts: their use to discern features of the environment around the star that produced them during its core’s collapse into a black hole. This type of analysis is possible because the spectrum of a gamma-ray burst afterglow is a straight-line continuum without features. 

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  • The Second Wave
    April 12, 2007
    PI(s): Deborah Jin, John Bohn
    Topic(s): Atomic & Molecular Physics

    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.

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  • Exploring a Cold New World
    April 12, 2007
    PI(s): Chris Greene, John Bohn, Jun Ye
    Topic(s): Atomic & Molecular Physics

    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.

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  • Deep Sea Diving
    April 10, 2007
    PI(s): Chris Greene
    Topic(s): Atomic & Molecular Physics

    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.

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  • Warm Side of the Force
    April 10, 2007
    PI(s): Eric Cornell
    Topic(s): Atomic & Molecular Physics, Nanoscience, Precision Measurement

    Small changes in the quantum fluctuations of free space are responsible for a variety of curious phenomena: a gecko’s ability to walk across ceilings, the evaporation of black holes via Hawking radiation, and the fact that warmer surfaces can be stickier than cold ones in micro- and nanoscale electromechanical systems (MEMS and NEMS). The tendency of tiny parts to stick together is a consequence of the Casimir force.

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  • Tunnel Vision
    March 02, 2007
    PI(s): Konrad Lehnert
    Topic(s): Nanoscience, Precision Measurement

    A key challenge in developing new nanotechnologies is figuring out a fast, low-noise technique for translating small mechanical motions into reasonable electronic signals. Solving this problem will one day make it possible to build electronic signal processing devices that are much more compact than their purely electronic counterparts. Much sooner, it will enable the design of advanced scanning tunneling microscopes that operate hundreds to thousands of times faster than current models.

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  • Jupiter Dust Filtration System
    February 22, 2007
    PI(s): Phil Armitage
    Topic(s): Astrophysics

    When astronomers observe a star surrounded by an accretion disk in visible light, they typically see radiation from the star at the center of the disk. When they observe the disk in the infrared, they typically see emission at a continuous range of wavelengths, ranging from short to long.

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  • Born in a Blowtorch
    February 10, 2007
    PI(s): Jeffrey Linsky
    Topic(s): Astrophysics

    Our Sun and its eight planets were born in a rough neighborhood nearly 5 billion years ago. Since then our star has traveled countless light years through the Milky Way, and our planet Earth has evolved the only intelligent life we know of in the Universe. Now, Earth's progeny are seeking to understand not only their own origins, but those of the Sun and its planets. 

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  • Spin City
    February 10, 2007
    PI(s): Steven Cundiff
    Topic(s): Atomic & Molecular Physics

    Researchers are investigating a new kind of microelectronics called spintronics. These devices will rely on the spindependent behavior of electrons in addition to (or even instead of) conventional charge-based circuitry. Researchers in physics and engineering anticipate that these devices will process data faster, use less power than today's conventional semiconductor devices, and work well in nanotechnologies, where quantum effects predominate. Spin-FETs (field effect transistors), spin-LEDs (light-emitting diodes), spin-RTDs (resonant tunneling devices), terahertz optical switches, and quantum computers are some of the multifunctional spintronic devices being envisioned.

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  • Ultimate Relaxation Experience
    February 07, 2007
    PI(s): John Bohn
    Topic(s): Atomic & Molecular Physics

    Scientists anticipate that cold molecules will allow them to explore all kinds of exciting new cold-matter physics. For instance, cold molecules should be able to interact with each other over much longer distances than atoms. They often exhibit an uneven distribution of electric charge called a dipole moment. Unfortunately, the complicated structures of ordinary "warm" molecules means it is very difficult to directly cool them to very cold temperatures.

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