Research Highlights

Mid-infrared (mid-IR) laser light is accomplishing some remarkable things at JILA. This relatively long-wavelength light (2–4 µm), when used to drive a process called high-harmonic generation, can produce bright beams of soft x-rays with all their punch packed into isolated ultrashort bursts. And, all this takes place in a tabletop-size apparatus. The soft x-rays bursts have pulse durations measured in tens to hundreds of attoseconds (10^-18 s).

Biomolecules may not always behave the same way in test tubes as they do in living cells, a fact underscored by important new work by former research associate Nick Dupuis, graduate student Erik Holmstrom, and Fellow David Nesbitt. The researchers found that under crowded conditions that begin to mimic those found in cells, single RNA molecules folded 35 times faster than in the dilute solutions typically used in test-tube experiments.

The Markus Raschke group has come up with an innovative way that may one day allow it to peer inside superconductors, new materials for solar cells, or even a single cell and identify the inner workings of these complex systems. The new method is able to determine where the different chemical constituents are located and how their spatial distribution determines their function.

Fellow Tom Perkins’ group is significantly closer to realizing its long-standing dream of using atomic force microscopy (AFM) to study how membrane proteins fold and unfold. Historically, scientists have used AFM to measure the mechanical forces needed to unfold individual proteins and the resulting increase in their lengths. However, the limitations of AFM itself have prevented researchers from watching the unfolding process in detail.

Graduate student Erik Holmstrom and Fellow David Nesbitt have applied their laboratory research on the rates of RNA folding and unfolding to the medically important enzyme telomerase. Telomerase employs both protein and RNA components to lengthen chromosomes, which are shortened every time they are copied.

The Regal-Lehnert collaboration has just taken a significant step towards the goal of one day building a quantum information network. Large-scale fiber-optic networks capable of preserving fragile quantum states (which encode information) will be necessary to realize the benefits of superfast quantum computing.

Quantum chaos just showed up in an ultracold gas of erbium atoms, and the Bohn theory group knows why. Theorists expect quantum chaos to appear when quantum mechanical objects get sufficiently complicated. But until now, scientists hadn’t realized that something as simple as a pair of colliding atoms could be complicated enough for quantum chaos to appear.

There’s exciting news from JILA’s ultracold molecule collaboration. The Jin, Ye, Holland, and Rey groups have come up with new theory (verified by experiment) that explains the suppression of chemical reactions between potassium-rubidium (KRb) molecules in the KRb quantum simulator. The main reason the molecules do not collide and react is continuous measurement of molecule loss from the simulator.

When Andy Almand-Hunter and his colleagues in the Cundiff group shined a laser on a sample of gallium arsenide (GaAs), the last thing they were expecting to create was a fog of liquid-like quantum droplets, which the group named "dropletons." Dropletons are a new, stable form of matter much like an ordinary liquid—with one key difference.

The groups of Fellow Adjoint Markus Raschke and Fellow Tom Perkins joined forces recently to shine light onto a bacterial membrane protein called bacteriorhodopsin (bR). They used a new infrared (IR) light imaging system with a spatial resolution and chemical sensitivity of just a few bR molecules. In their experiment, the tip of an atomic force microscope (AFM) acted like an antenna for the IR light, focusing it onto the sample.

Fellows Mitch Begelman and Phil Armitage have just solved the 40-year old mystery of what causes the gas of stellar debris surrounding black holes in binaries to flip back and forth cyclically between a spherical cloud and a luminous disk.

Black holes have a new item on their dinner menu: a three-dimensional glowing sphere of stellar debris that looks like a star. The sphere provides a sumptuous main course for a supermassive black hole, while emitting excess energy via jets erupting from its polar regions. The idea for this new type of gourmet feast for black holes comes compliments of graduate student Eric Coughlin and Fellow Mitch Begelman.

Real-world quantum mechanics may not always work exactly like the simple picture presented in textbooks, according to observations made by research associate Gaël Nardin and his colleagues in the Cundiff group.

JILA and NIST labs are well on the way to creating astonishingly accurate optical atomic clocks based on the neutral atoms strontium (Sr) and ytterbium (Yb). The new technologies are already capable of the most meticulous timekeeping in human history.

Capturing and controlling the fleeting dance of electrons as they rearrange during a chemical reaction has been a long-standing challenge in science for several decades. Since electrons are much lighter than atoms, they can respond almost instantaneously – on time scales of hundreds of attoseconds, where an attosecond is 10^-18 s.

The Cornell and Jin groups have just met the challenge of creating and studying an extremely strongly interacting Bose-Einstein condensate (BEC). This feat was reported in Nature Physics online January 12, 2014. An example of an ordinary weakly interacting Bose-Einstein condensate (BEC) is a quantum gas of rubidium atoms (⁸⁵Rb) all piled up in a little ball whose temperature is a chilly 10 nK.

Physicists wonder about some pretty strange things. For instance, one burning question is: How round is the electron? While the simplest picture of the electron is a perfect sphere, it is possible that it is instead shaped like an egg. The egg shape would look a bit like a tiny separation of positive and negative charges. Physicists call this kind of charge separation an electric dipole moment, or EDM. The existence of an EDM in the electron or any other subatomic particle will have a profound impact on our understanding of the fundamental laws of physics. 

Tauno Palomaki and his colleagues in the Lehnert group have just gone where no one has gone before: They’ve entangled the quantum motion of a vibrating drum with the quantum state of a moving electrical pulse. What’s more, they figured out how to storehalf of this novel entangled state in the drum (which is tiny compared to a musical drum, but huge compared to the atoms or molecules normally entangled in a lab). The drum can then generate another electrical pulse that is entangled with the first one!  This amazing feat was reported in Science.

Research associate Tom Purdy and his colleagues in the Regal group have just built an even better miniature light-powered machine that can now strip away noise from a laser beam. Their secret: a creative workaround of a quantum limit imposed by the Heisenberg Uncertainty Principle. This limit makes it impossible to simultaneously reduce the noise on both the amplitude and phase of light inside interferometers and other high-tech instruments that detect miniscule position changes.

Research associate Bo Yan and his colleagues recently observed spin exchanges in ultracold potassium-rubidium (KRb) molecules inside an optical lattice (a crystal of light formed by interacting laser beams). In solid materials, such spin exchanges are the building blocks of advanced materials and exotic behavior.