Research Highlights

Astrophysics
Interstellar Spaghetti, with Meatballs Inside
Published: August 16, 2015

When an ordinary star like our Sun wanders very close to a supermassive black hole, it’s very bad news for the star. The immense gravitational pull of the black hole (i.e., tidal forces) overcomes the forces of gravity holding the star together and literally pulls the star apart. Over time, the black hole swallows half of the star stuff, while the other half escapes into the interstellar medium. This destructive encounter between a supermassive black hole and a star is known as a tidal disruption event.

PI: Mitch Begelman
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Astrophysics
Beautiful & Twisted
Published: August 14, 2015

Ever wondered how magnetic pressure alone might be able to maintain the structure of an accretion disk around a black hole in an x-ray binary system? Fellow Mitch Begelman recently gave the idea a lot of thought. And, in the process of working on the idea with Fellow Phil Armitage and Chris Reynolds of the University of Maryland, Begelman came up with a new model for accretion disks around black holes in x-ray binary systems, such as the one shown in the picture.

PI: Mitch Begelman | PI: Phil Armitage
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Atomic & Molecular Physics
Lattice Light and the Chips
Published: August 10, 2015

Compact and transportable optical lattices are coming soon to a laboratory near you, thanks to the Anderson group and its spin-off company, ColdQuanta. A new robust on-chip lattice system (which measures 2.3 cm on a side) is now commercially available. The chip comes with a miniature vacuum system, lasers, and mounting platform.

PI: Dana Anderson
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Astrophysics
Multitalented Lyman-α
Published: July 16, 2015

For astrophysicists like Fellow Jeff Linsky, the Lyman-α spectral line of atomic hydrogen is a powerful tool for investigating the stellar winds emitted by stars, the deuterium/hydrogen (D/H) ratio in the Galaxy, the excited states of hydrogen molecules and carbon monoxide in the environments around young stars, and photochemical processes that create oxygen in the atmospheres of planets around other stars, or exoplanets.

PI: Jeffrey Linsky
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Biophysics
Custom-Made RNA
Published: May 11, 2015

A wildly successful JILA (Nesbitt Group)-NIH collaboration is opening the door to studies of RNA behavior, including binding, folding and other factors that affect structural changes of RNA from living organisms. Such structural changes determine RNA enzymatic functions, including the regulation of genetic information.

PI: David Nesbitt
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Laser Physics
Every Generation Needs a New Revolution
Published: April 30, 2015

For decades after the invention of the red ruby laser in 1960, bright laser-like beams were confined to the infrared, visible, and ultraviolet region of the spectrum. Today there’s an exciting revolution afoot: new coherent x-ray beams are now practical, including the EUV beams gracing the cover of the May 1, 2015, special issue of Science honoring the International Year of Light. The same issue features an article entitled “Beyond Crystallography: Diffractive Imaging Using Coherent X-ray Light Sources” that celebrates the revolutionary advances in both large- and small-scale coherent x-ray sources that are transforming imaging in the 21st century.

PI: Margaret Murnane
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Precision Measurement
About Time
Published: April 21, 2015

The Ye group has just improved the accuracy of the world’s best optical atomic clock by another factor of three and set a new record for clock stability. The accuracy and stability of the improved strontium lattice optical clocks is now about 2 x 10-18, or the equivalent of not varying from perfect time by more than one second in 15 billion years—more than the age of the Universe. Clocks like the Ye Group optical lattice clocks are now so exquisitely precise that they may have outpaced traditional applications for timekeeping such as navigation (GPS) and communications.

PI: Jun Ye
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Atomic & Molecular Physics
A Bug’s Life
Published: April 20, 2015

The Ye Group recently investigated what first appeared to be a “bug” in an experiment and made an unexpected discovery about a new way to generate high-harmonic light using molecular gases rather than gases of noble atoms. Graduate student Craig Benko and his colleagues in the Ye group were studying the interaction of light from an extreme ultraviolet (XUV) frequency comb with molecules of nitrous oxide, or laughing gas (N2O), when they noticed unusual perturbations in the laser spectrum.

PI: Jun Ye
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Nanoscience
Come Close to Me
Published: March 23, 2015

One of the great challenges in the semiconductor and electronics industries is that as nanoscale features get smaller and processes get faster, enormous amounts of heat need to be quickly carried away from the nanostructures. The Kapteyn/Murnane group has made the counter-intuitive discovery that it is easier to cool these nanostructures when they are arranged closely together. The researchers also developed a theory to explain this unexpected new behavior.

PI: Henry Kapteyn | PI: Margaret Murnane
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Astrophysics
Gamma Ray Exposé
Published: March 11, 2015

Supermassive black holes at the center of active galaxies are known as blazars when they are extremely bright and produce powerful jets of matter and radiation visible along the line of sight to the Earth. Blazars can appear up to a thousand times more luminous than ordinary galaxies, and their associated jets are so powerful they can travel millions of light years across the Universe. Blazar jets produce flares of high-energy gamma rays that are detected by ground- and space-based observatories.

PI: Mitch Begelman
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Atomic & Molecular Physics
An Ultrafast Photoelectric Adventure
Published: March 02, 2015

The photoelectric effect has been well known since the publication of Albert Einstein’s 1905 paper explaining that quantized particles of light can stimulate the emission of electrons from materials. The nature of this quantum mechanical effect is closely related to the question how much time it might take for an electron to leave a material such as a helium atom.

PI: Agnieszka Jaron-Becker | PI: Andreas Becker
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Atomic & Molecular Physics | Quantum Information Science & Technology
Terms of Entanglement
Published: February 27, 2015

When the Rey theory group first modeled a quantum system at JILA, it investigated the interactions of strontium atoms in the Ye group’s strontium-lattice clock. The quantum behavior of these collective interactions was relatively simple to model. However, the group has now successfully tackled some more complicated systems, including the ultracold polar KRb molecule experiment run by the Jin and Ye groups.

PI: Deborah Jin
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Atomic & Molecular Physics | Quantum Information Science & Technology
Terms of Entanglement
Published: February 27, 2015

When the Rey theory group first modeled a quantum system at JILA, it investigated the interactions of strontium atoms in the Ye group’s strontium-lattice clock. The quantum behavior of these collective interactions was relatively simple to model. However, the group has now successfully tackled some more complicated systems, including the ultracold polar KRb molecule experiment run by the Jin and Ye groups. In the process, the group has developed a new theory that will open the door to probing quantum spin behavior in real materials; atomic, molecular and optical gases; and other complex systems. The new theory promises important insights in different areas of physics, quantum information science, and biology.

PI: Ana Maria Rey
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Biophysics
Mutant Chronicles
Published: January 20, 2015

Because red fluorescent proteins are important tools for cellular imaging, the Jimenez group is working to improve them to further biophysics research. The group’s quest for a better red-fluorescent protein began with a computer simulation of a protein called mCherry that fluoresces red light after laser illumination. The simulation identified a floppy (i.e., less stable) portion of the protein “barrel” enclosing the red-light emitting compound, or chromophore. The thought was that when the barrel flopped open, it would allow oxygen in to degrade the chromophore, thus destroying its ability to fluoresce.

PI: Ralph Jimenez
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Atomic & Molecular Physics
Metamorphosis
Published: January 07, 2015

A grand challenge of ultracold physics is figuring out how fermions become bosons. This is an important question because the tiniest quantum particles of matter are all fermions. However, these fermions can form larger chunks of matter, such as atoms and molecules, which can be either fermions or bosons.

PI: Deborah Jin
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Laser Physics
The Polarized eXpress
Published: December 10, 2014

Until recently, researchers who wanted to understand how magnetic materials work had to reserve time on a large, stadium-sized X-ray machine called a synchrotron. Synchrotrons can produce X-ray beams that can be sculpted very precisely to capture how the spins in magnetic materials work together to give us beautiful and useful magnetic properties – for example to store data in a computer hard drive. But now, thanks to Patrik Grychtol and his colleagues in the Kapteyn/Murnane group, there’s a way to conduct this kind of research in a small university laboratory.

PI: Henry Kapteyn | PI: Margaret Murnane
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Atomic & Molecular Physics
Exciting Adventures in Coupling
Published: October 31, 2014

New theory describing the spin behavior of ultracold polar molecules is opening the door to explorations of exciting, new physics in JILA’s cold molecular lab, operated by the Jin and Ye groups. According to the Rey theory group and its collaborators, ultracold dipolar molecules can do even more interesting things than swapping spins.

PI: Ana Maria Rey
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Quantum Information Science & Technology
The Quantum Identity Crisis
Published: October 14, 2014

Dynamical phase transitions in the quantum world are wildly noisy and chaotic. They don’t look anything like the phase transitions we observe in our everyday world. In Colorado, we see phase transitions caused by temperature changes all the time: snow banks melting in the spring, water boiling on the stove, slick spots on the sidewalk after the first freeze. Quantum phase transitions happen, too, but not because of temperature changes. Instead, they occur as a kind of quantum “metamorphosis” when a system at zero temperature shifts between completely distinct forms.

PI: James Thompson | PI: Murray Holland
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Astrophysics
When You Feast Upon a Star
Published: August 25, 2014

A Be star is a luminous, blue B-type star with distinctive spectral lines that can provide two types of feasts (tasty snacks or full-scale banquets) for a former companion star in a binary system. The feasting begins when the companion star goes supernova and becomes a neutron star or, more rarely, a black hole. Typically, the companion blows up with enough force to kick itself into an eccentric (elliptical) orbit that is misaligned with respect to the Be star’s orbit.

PI: Phil Armitage
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Atomic & Molecular Physics
Atoms, Atoms, Frozen Tight in the Crystals of the Light, What Immortal Hand or Eye Could Frame Thy Fearful Symmetry?
Published: August 18, 2014

Symmetries described by SU(N) group theory made it possible for physicists in the 1950s to explain how quarks combine to make protons and neutrons and JILA theorists in 2013 to model the behavior of atoms inside a laser. Now, the Ye group has observed a manifestation of SU(N≤10) symmetry in the magnetic behavior of strontium-87 (87Sr) atoms trapped in crystals of light created by intersecting laser beams inside a quantum simulator (originally developed as an optical atomic clock).

PI: Ana Maria Rey | PI: Jun Ye
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