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quantum_mechanic_title  By Dan Sadowsky
Photos by Lisa Currier

Kalista Smith ’01 flips her 64-page thesis to a photograph that shows a bright ball of light shining through a container of transparent glass. The photo captures a rare and long-awaited phenomenon: normally zippy rubidium atoms frozen in the crosshairs of seven laser beams.Kalista

In slowing to a mere crawl atoms that typically dart and swirl around a room at 450 miles per hour, the 23-year-old Smith not only proved the functionality of Reed’s magneto-optical trap, she also replicated an experiment that won a trio of physicists the Nobel Prize four years earlier. What’s more, she went a step beyond the work of four preceding Reed College physics majors—all of whom penned their theses on various elements and theoretical foundations of the trap, but none of whom actually got it to work.

“Every student who took it on was hoping they’d be the one,” says physics professor John Essick, who jointly advised Smith as well as the previous atom-trapping aspirants.

That Smith succeeded speaks to her “fearlessness and perseverance,” says visiting physics professor Morgan Mitchell, who also advised Smith. “She was undaunted by the number of different things she needed to tackle in order for it to work,” he says. Moving beyond previous efforts, he adds, required “getting to know intimately every single part of an extremely complex apparatus.”

Smith attained that level of intimacy by working doggedly throughout her senior year in a darkened second-floor laboratory to try to demonstrate the trap’s functionality. She took satisfaction from the daily grind of lab work and a challenge that blended her relatively new interests in the fields of quantum mechanics, optics, and electrodynamics. “Once I saw this table,” says the Salt Lake City native, sizing up the array of gadgets and gizmos that make up the trap, “I said, ‘Wow, I really want to work with all that stuff.’”

FluorescenceMagneto-optical atom traps are complicated devices. They use a weak magnetic field and circularly polarized light to slow the movement of atoms to a virtual halt, allowing researchers to study them in new ways. Reed’s is made up of nearly 40 elements of tabletop equipment—including lenses, prisms, lasers, an ion pump, and a vacuum chamber—and another dozen pieces of electronic gear.

Most of it rests on a one-ton sheet of stainless steel about the size of a billiard table, evenly perforated by small screwholes that allow tabletop pieces to be fastened down. The focal point of the apparatus is a small tube of transparent glass known as a “trapping cell,” which contains a thin metal filament filled with rubidium atoms.

 

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