Graduate student Yingyi Zhang has won the People’s Choice Award in the 2011 Mahato Memorial Event Photo Contest sponsored by the Pratt School of Engineering and the Duke Graduate School. Zhang’s photo shows the red fluorescent light emitted by a cloud of atoms cooled nearly to absolute zero. The Mahato contest, “Envisioning the Invisible,” was established to honor the memory of Abhijit Mahato, an engineering student at Duke who was murdered in January 2008. Zhang says she carries a compact camera with her all the time. “I have to have it to take pictures when I notice something interesting,” she says. In this case, she was fascinated by the red light inside a vacuum chamber where atoms were being super-cooled in the lab of her advisor Professor Emeritus John Thomas, now at N.C. State University.
Lasers coming from six directions (up, down, back, front, left, right) still the movement of the atoms until they are just a few microdegrees Kelvin. When the atoms are cooling down, they absorb some photons and they emit some photons. The photons they emit are visible in all directions, and we perceive them as red light. “As long as the lasers are there, the atoms stay in the center and you can see the fluorescent light,” she says. “The first time I saw the atoms floating in the middle of the chamber, I thought [this is] something I cannot see other places. It’s quite amazing.” It turns out these super-cooled atoms behave in some very unusual ways that are similar to other systems, which can’t be studied in labs—such as the universe microseconds after the Big Bang, and quark-gluon plasma. Zhang likes the idea of a simple system that can be used to study other, less accessible systems. She’s also enchanted by the idea of those atoms floating in the center of the chamber. “This is something I appreciate so I want to show it to other people,” she says. “That’s the reason why I submitted that photo.” Click here to see the other winners. Click here to see the 21 finalists. In 2010, physics graduate student Jie Ren won first prize in the contest with her photo of sand strings. Ren studies the behavior of granular materials in the lab of Bob Behringer. Click here to see her photograph.