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Friday, December 9, 2011

New Atoms Interact To Observe Enigmatic Particle

quantum impact
Needs high level of technology currently is growing. To meet that need, the researchers must able to find a way or a new theory to be able to understand other natural phenomena. One of them is the technology of superconducting materials.

Physicists at the National Institute of Standards and Technology (NIST) have found a way to manipulate atoms’ internal states with lasers that dramatically influences their interactions in specific ways. Such light-tweaked atoms can be used as proxies to study important phenomena that would be difficult or impossible to study in other contexts. 

Superconducting material is the result of particle interactions. So, to be able to produce superconducting material with good quality, then scientists should be able to understand the interaction between the particles. The more interactions that are known or creating new interactions then the hopes of generating high levels of superconducting materials will soon be realized. Because, from that understanding, then how the workings of superconducting materials with high temperature can be understood with very well.

Because most materials are complicated systems, it is difficult to study or engineer the interactions between the constituent electrons. Researchers at NIST build physically analogous systems using supercooled atoms to learn more about how materials with these properties work. Thus, success in manipulating the internal state of the atom will greatly assist researchers in quantum computation.

“Basically, we’re able to simulate these complicated systems and observe how they work in slow motion,” says Ian Spielman, a physicist at NIST and fellow of the Joint Quantum Institute (JQI), a collaborative enterprise of NIST and the University of Maryland.

According to Ross Williams, a postdoctoral researcher at NIST, cold atom experiments are good for studying many body systems because they offer a high degree of control over position and behavior of the atoms.

“First, we trap rubidium-87 atoms using magnetic fields and cool them down to 100 nanokelvins,” says Williams. “At these temperatures, they become what’s known as a Bose-Einstein condensate. Cooling the atoms this much makes them really sluggish, and once we see that they are moving slowly enough, we use lasers to ‘dress’ the atoms, or mix together different energy states within them. Once we have dressed the atoms, we split the condensate, collide the two parts, and then see how they interact.”

According to Williams, without being laser-dressed, simple, low-energy interactions dominate how the atoms scatter as they come together. While in this state, the atoms bang into each other and scatter to form a uniform sphere that looks the same from every direction, which doesn’t reveal much about how the atoms interacted.

When dressed, however, the atoms tended to scatter in certain directions and form interesting shapes indicative of the influence of new, more complicated interactions, which aren’t normally seen in ultracold atom systems. The ability to induce them allows researchers to explore a whole new range of exciting quantum phenomena in these systems.

While the researchers used rubidium atoms, which are bosons (bosons are subatomic particles that obey Bose–Einstein statistics. Several bosons can occupy the same quantum state), for this experiment, they are modifying the scheme to study ultracold fermions (fermion is any particle which obeys the Fermi–Dirac statistics and follows the Pauli exclusion principle), a different species of particle. The group hopes to find evidence of the Majorana fermion, an enigmatic, still theoretical kind of particle that is involved in superconducting systems important to quantum computation.

“A lot of people are looking for the Majorana fermion,” says Williams. “It would be great if our approach helped us to be the first.”

Source: http://www.nist.gov/pml/div684/atoms-dressed-with-light-show-new-interactions-could-reveal-way-to-observe-enigmatic-particle.cfm

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