Research Highlights

Displaying 261 - 280 of 469
Atomic & Molecular Physics
Everything's Cool with Atom
Published: November 29, 2012

The Regal group recently completed a nifty feat that had never been done before: The researchers grabbed onto a single trapped rubidium atom (87Rb) and placed it in its quantum ground state. This experiment has identified an important source of cold atoms that can be arbitrarily manipulated for investigations of quantum simulations and quantum logic gates in future high-speed computers.

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PI(s):
Cindy Regal
Atomic & Molecular Physics
Close Encounters with the Contact
Published: October 22, 2012

The Jin and Cornell groups have discovered irrefutable evidence for the contact. The contact appears in ultracold gases under conditions when the atoms are close “contact” in a Bose-Einstein condensate, or BEC.  Like pressure, volume, and temperature, the contact is an important property of ultracold ensembles of atoms.  The contact is particularly important when the atoms interact with each other, since the contact tells you how likely it is that an atom in the ensemble is having a close encounter with another atom.

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PI(s):
Deborah Jin | Eric Cornell
Astrophysics
A More Perfectly Understood Union
Published: October 18, 2012

Research associate Bruno Giacomazzo recently studied the effects of magnetic fields and matter on the likelihood that the merger of two black holes will produce jets of light of different frequencies ranging from radio waves to X-rays. If such signals are generated, it may be possible to detect them with ground- or space-based observatories. Their detection would help astronomers identify and study the unions of supermassive black holes that occur after galaxies collide. Supermassive black holes are found at the centers of most galaxies in the Universe.

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PI(s):
Other
Atomic & Molecular Physics
Sizzling Vibrations
Published: October 18, 2012

Former research associate Antonio Picón, research associate Agnieszka Jaron-Becker, and Fellow Andreas Becker have discovered a way to make the hydrogen molecular ion (H2+) fall apart into its constituent atoms without exciting or ionizing the electron. This startling finding was a big surprise for the researchers, who recently figured out how to do something that conventional wisdom said was difficult, if not downright impossible.

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PI(s):
Andreas Becker
Astrophysics
Messages from the Abyss
Published: October 10, 2012

Many neutron stars are surrounded by accretion disks. The disks are often made up of matter pulled in by the neutron star’s gravity from a companion star in a binary system. Over time, the neutron stars can swallow so much additional material that they collapse into black holes.

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PI(s):
Rosalba Perna
Atomic & Molecular Physics
Scratching the Surface
Published: October 08, 2012

Members of the Jin group found a way to measure for the first time the a type of abstract “surface” in a gas of ultracold atoms that had been predicted in 1926 but not previously observed. Jin and her colleagues are leading researchers in the field of ultracold Fermi gases made up of thousands to millions of fermions.

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PI(s):
Deborah Jin
Precision Measurement
New Silicon Cavity Silences Laser Noise
Published: September 12, 2012

Researchers from a German national laboratory, the Physikalisch-Technische Bundesanstalt (PTB) have collaborated with Fellow Jun Ye, Visiting Fellow Lisheng Chen (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences), and graduate student Mike Martin to come up with a clever approach to reducing heat-related “noise” in interferometers. 

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PI(s):
Jun Ye
Atomic & Molecular Physics
The Spider's Secret
Published: August 22, 2012

Graduate student Dan Hickstein (Kapteyn/Murnane group) recently investigated the behavior of electrons ripped from atoms and molecules by intense infrared laser pulses. He and his colleagues collected the liberated electrons onto a detector where they formed intricate patterns that looked a lot like giant spiders. 

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PI(s):
Henry Kapteyn | Margaret Murnane
Chemical Physics
Way Faster than a Speeding Bullet
Published: June 18, 2012

The interface between a gas and a solid is a remarkable environment for new investigations. Lots of fascinating chemistry takes place there, including catalysis. Catalysis is acceleration of a chemical reaction that is caused by an element like platinum that remains unchanged by a chemical reaction. For instance platinum catalyzes the transformation of carbon monoxide (CO) into carbon dioxide (CO2) in automobile catalytic converters. A better understanding of catalysis could improve the efficiency of manufacturing important chemicals as well as expanding our fundamental knowledge of chemistry.

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PI(s):
David Nesbitt
Atomic & Molecular Physics
X-Ray Visionaries
Published: June 07, 2012

The Kapteyn/Murnane group had the idea that it might be possible to produce bright, laser-like beams of x-rays using an ultrafast laser that fits on a small optics table. It was one of those “it probably can’t be done, but we have to try” moments that motivated them to put together a team that includes the Becker theory group, and 16 collaborators in New York, Austria, and Spain. The lead scientist on this effort, Dr. Tenio Popmintchev, was most concerned about the possibility of an explosion, because to generate x-rays at high photon energies, the laser needed to be focused into a fiber containing high-density helium gas at pressures as high as 80 atmospheres. Eighty atmospheres is 80 times the normal air pressure at sea level.

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PI(s):
Henry Kapteyn | Margaret Murnane
Biophysics
RNA Folding: The Rest of the Story
Published: June 06, 2012

The Nesbitt group has been investigating RNA folding since the early 2000s. The group’s goal has been to gain a detailed understanding of the relationship between structure and function in this important biomolecule. One challenge has been figuring out how unfolded RNA molecules assume the proper three-dimensional (3D) shape to perform their biological activities. To accomplish this, the researchers have shown how biologically active RNA is able to neutralize negative charges that end up in close proximity to each other after folding into a 3D structure.

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PI(s):
David Nesbitt
Quantum Information Science & Technology
New Flavors of Quantum Magnetism
Published: May 24, 2012

News Flash!  The Rey group has discovered another good reason for using alkaline-earth atoms, such as strontium (Sr) or Ytterbium (Yb), in experimental quantum simulators. Quantum simulators are systems that mimic interesting materials or mathematical models in a very controlled way. The new reason for using alkaline earth atoms in such systems comes from the fact that their nuclei come in as many as 10 different magnetic flavors, i.e., their spins can be in 10 different quantum states.

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PI(s):
Ana Maria Rey
Other
New Beginnings: JILA welcomes the Janus supercomputer
Published: May 09, 2012

In Roman mythology, Janus is the god of beginnings and transitions, of doors and bridges, as well as endings and time.  The aptly named Janus supercomputer at CU is bringing new opportunities in high-performance research computing to JILA. Since the fall of 2010, JILA groups directed by Andreas Becker, Mitch Begelman, Chris Greene, Ana Maria Rey, and Juri Toomre have used more than 25 million CPU hours on Janus for research in astrophysics and AMO physics.

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Astrophysics
Diary of a Binge Eater
Published: May 03, 2012

Fellow Mitch Begelman and his colleagues came up with the idea of quasistars to explain the origin of the supermassive black holes found at the center of most galaxies. According to Begelman, quasistars formed when massive amounts of gas were funneled into the center of protogalaxies. This prodigious amount of gas collapsed directly into black holes without forming stars.

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PI(s):
Mitch Begelman
Astrophysics
Molding a Star System over 50 Million Years
Published: April 20, 2012

Giant planets form inside a disk of gas and dust orbiting a new star. At first, gravitational interactions between the disk and the planets will keep planetary orbits circular, according to Fellow Phil Armitage. But, once the disk begins to disperse, things get very interesting.

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PI(s):
Phil Armitage
Laser Physics
The Laser with Perfect Pitch
Published: April 04, 2012

The Thompson group, with theory help from the Holland group, recently demonstrated a superradiant laser that escapes the “echo chamber” problem that limits the best lasers. To understand this problem, imagine an opera singer practicing in an echo chamber. The singer hears his own voice echo from the walls of the room. He constantly adjusts his pitch to match that of his echo from some time before. But, if the walls of the room vibrate, then the singer’s echo will be shifted in pitch after bouncing off of the walls. As a result, if the singer initially started singing an A, he may eventually end up singing a B flat, or a G sharp, or any other random note — spoiling a perfectly good night at the opera.

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PI(s):
James Thompson
Astrophysics
Secrets of a Celestial Accelerator
Published: March 20, 2012

On Earth, people use enormous linear accelerators and synchrotrons for such purposes as high-energy physics experiments, chemical composition analysis, and drug research. Linear accelerators ramp up the speeds of electrons and other charged subatomic particles close to the speed of light. Synchrotrons also accelerate charged particles (in a circular track) that, when deflected through magnetic fields, create extremely bright high-energy light. 

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PI(s):
Mitch Begelman
Laser Physics
The Secret Life of Magnets
Published: March 15, 2012

The Kapteyn/Murnane group and scientists from NIST Boulder and Germany have figured out how the interaction of an ultrafast laser with a metal alloy of iron and nickel destroys the metal’s magnetism. In a recent experiment, the researchers were able to observe how individual bits of quantum mechanical magnetization known as “spin” behaved after the metal was heated with the laser.

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PI(s):
Henry Kapteyn | Margaret Murnane
Atomic & Molecular Physics
Variation on an Infinity of Triangles
Published: February 21, 2012

The Greene group has just discovered some weird quantum states of ultracold fermions that are also dipoles. Dipoles are particles with small positively and negatively charged ends. Atoms (or molecules) that are fermions cannot occupy the same quantum state — unlike the neighborly bosons that readily occupy the same state and form Bose-Einstein condensates at ultracold temperatures. The new theoretical study was interesting because it explored what would happen to dipolar fermions under the same conditions that cause dipolar bosons to form infinitely many three-atom molecules even though no two bosons ever form a molecule under these conditions!

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PI(s):
Chris Greene
Laser Physics
The Indomitable Ruler of Light
Published: February 02, 2012

The Ye group has created the world’s first “ruler of light” in the extreme ultraviolet (XUV). The new ruler is also known more formally as the XUV frequency comb. The comb consists of hundreds of equally spaced “colors” that function in precision measurement like the tics on an ordinary ruler. The amazing thing about this ruler is that XUV colors have such short wavelengths they aren’t even visible to the human eye. The wavelengths of the XUV colors range from about 120 nm to about 50 nm — far shorter than the shortest visible light at 400 nm. “Seeing” the colors in the XUV ruler requires special instruments in the laboratory. With these instruments, the new ruler is opening up whole new vistas of research.

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PI(s):
Jun Ye