Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

JILA scientists create first dense gas of ultracold 'polar' molecules

22.09.2008
Milestone portends advances in quantum information, designer chemistry, precision metrology

Scientists at JILA, a joint institute of the National Institute of Standards and Technology (NIST)and the University of Colorado at Boulder (CU-Boulder), have applied their expertise in ultracold atoms and lasers to produce the first high-density gas of ultracold molecules—two different atoms bonded together—that are both stable and capable of strong interactions.

The long-sought milestone in physics has potential applications in quantum computing, precision measurement and designer chemistry.

Described in the Sept. 18 issue of Science Express,* JILA's creation of ultracold "polar" molecules—featuring a positive electric charge at one end and a negative charge at the other—paves the way for controlled interactions of molecules separated by relatively long distances, offering a richer selection of features than is possible with individual atoms and potentially leading to new states of matter.

"Ultracold polar molecules really represent now one of the hottest frontiers in physics," says NIST/JILA Fellow Jun Ye, an author of the paper. "They are potentially a new form of matter, a quantum gas with strong interactions that vary by direction and that you can control using external tools such as electric fields."

The authors say atoms are like basketballs, round and somewhat featureless, whereas molecules are more like footballs, with angles, and characteristics that vary by direction.

"This is really a big deal," says NIST/JILA Fellow Deborah Jin, another author of the new paper. "This is something people have been trying to do for a long time, using all kinds of different approaches."

Jin and Ye are adjoint professors of physics at CU-Boulder and both teach undergraduate and graduate students. Other authors of the paper include a NIST theorist at the Joint Quantum Institute at the University of Maryland and a theorist at Temple University in Philadelphia.

Two types of atoms are found in nature—fermions, which are made of an odd number of subatomic components (protons and neutrons), and bosons, made of an even number of subatomic components. The JILA group combined potassium and rubidium, which are different classes of atoms (a slightly negative fermion and a slightly positive boson, respectively). The resulting molecules exhibit a permanent and significant differential in electric charge, which, along with the ultracold temperatures and high density, allows the molecules to exert strong forces on each other.

The molecules are in the lowest possible vibrational energy state and are not rotating, so they are relatively stable and easy to control. They also have what is considered a long lifespan for the quantum world, lasting about 30 milliseconds (thousandths of a second).

JILA's ultracold polar gas has a density of 10 quadrillion molecules per cubic centimeter, a temperature of 350 nanoKelvin above absolute zero (about minus 273 degrees Celsius or minus 459 degrees Fahrenheit), and a measurable separation of electric charge.

The process for making the molecules begins with a gas mixture of very cold potassium and rubidium atoms confined by a laser beam. By sweeping a precisely tuned magnetic field across the atoms, scientists create large, weakly bound molecules containing one atom of each type. This technique was pioneered by Jin in her 2003 demonstration of the world's first Fermi pair condensate.

At this stage the molecules are very large and possess a high amount of internal energy, which allows them to decay and heat up rapidly, both undesirable effects for practical applications. The scientists faced the considerable challenge of efficiently converting atoms that are far apart into tightly bound molecules, without allowing the released binding energy to heat the gas.

In a process that Jin describes as "chemistry without explosions," scientists used two lasers operating at different frequencies—each resonating with a different energy jump in the molecules—to convert the binding energy into light instead of heat. The molecules absorb near-infrared laser light and release red light. In the process, more than 80 percent of the molecules are converted, through an intermediate energy state, to the lowest and most stable energy level.

A key to success was the development of detailed theory for the potassiumrubidium molecule's energy states to identify the appropriate intermediate state and select the laser colors for optimal control. In addition, both lasers were locked to an optical frequency comb, a precise measurement tool invented in part at NIST and JILA, synchronizing the two signals perfectly.

The research described in Science is part of a larger NIST/JILA effort to develop techniques to understand and control the complex features of molecules and their interactions. Practical benefits could include new chemical reactions and processes for making designer materials and improving energy production, new methods for quantum computing using charged molecules as quantum bits, new tools for precision measurement such as optical molecular clocks or molecular systems that enable searches for new theories of physics beyond the Standard Model, and improved understanding of condensed matter phenomena such as colossal magnetoresistance (for improved data storage and processing) and superconductivity (for perfectly efficient electric power transmission).

JILA researchers are now working to improve the efficiency of producing tightly bound polar molecules and extend molecule lifetimes. They also plan to apply the new molecules to explore new scientific directions.

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Physics and Astronomy:

nachricht Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science

nachricht Artificial agent designs quantum experiments
19.01.2018 | Universität Innsbruck

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>