John Bohn grew up in Fort Wayne, Indiana, drawn to science by repeated viewings of Star Trek. He kept busy doing experiments in his basement chemistry lab, taking apart old radios, and playing Little League baseball. His fondest memory of Little League was the year he was one of the top batters in his league, an accomplishment he attributes to his team’s pitcher, who was the only one in the league who could throw a curve ball. He dreamed many nights of playing second base like his hero Joe Morgan.
The idea of physics as a career began to fester in Bohn’s subconscious when he was an undergraduate at the University of Chicago, where he majored in math. Just for fun, he took all the physics courses he could find. He also signed up to work with Ugo Fano on a senior thesis on theoretical physics. “I did it for two reasons,” Bohn remembers. “Physics was already more interesting to me, and the math department didn’t have a senior thesis requirement.”
It took two years of graduate work in math to convince Bohn to accept his true destiny as a physicist. He returned to the University of Chicago for graduate studies in theoretical physics. Working once again under Ugo Fano, he worked on “ridge resonances” to characterize what happens to a helium atom when both of its electrons get excited. (A ridge is where the electrons are at the maximum of their potential energy.) “It was a classic two-body problem,” Bohn says.
Bohn met his wife, Deborah Jin, in graduate school. “There was this serious, studious girl sitting in front of my first class, paying attention while I was dozing off in the back of the room,” he recalls. “Then I noticed she was beautiful. That was an unbeatable combination.”
The couple married in 1994, a year before they obtained their doctorates in physics. The two physicists quickly encountered another classic two-body problem in securing postdocs. Both had to make compromises to end up at JILA. “Debbie abandoned her field (condensed matter) to work with Eric Cornell,” Bohn recalls. “At first, she didn’t even know what a laser was. She came home with stacks of optics books, with things in them like how to align lenses and whatever.”
Meanwhile, Bohn had been awarded a prestigious National Research Council fellowship to work with theorist Paul Julienne at NIST-Gaithersburg. “Fortunately, Paul was very nice about our situation and allowed me to live and work in Boulder,” Bohn says. “Around Gaithersburg, I was known as the ‘virtual postdoc’ for two years.” In reality, Bohn worked a lot with Chris Greene. He also watched proudly as Jin achieved national recognition for her cold-atom experiments with Cornell. “I was in the audience when she filled in for Eric at the plenary session at the DAMOP conference in Ann Arbor (Michigan) in 1996,” Bohn recalls. “I knew she had extraordinary talent, but right then, bam, everybody else knew it, too.”
In 1997, Jin was hired by NIST as an Associate Fellow of JILA and Assistant Professor Adjoint of Physics at CU. Though Bohn was not offered a faculty position at that time, the couple decided to take their chances and stay in Boulder. The gamble paid off. In 2000, Bohn was hired as an assistant research professor at CU and became became an associate fellow of JILA. Today, Bohn is a Fellow of JILA and Research Professor of Physics at CU. He leads a large theory group that focuses on two main research problems: (1) ultracold and cold collisions and chemistry of molecules in quantum gases and (2) the effects of dipoles on Bose-Einstein condensates of polar atoms and molecules. His efforts on ultracold molecule collisions and chemistry have led to a collaboration with experimentalists Jin and Jun Ye on ground-breaking studies of the chemistry of ultracold potassium-rubidium (KRb) atoms formed in quantum gases just a few millionths of a degree above absolute zero.
Bohn is a Fellow of the American Physical Society.
In addition to his work in physics theory, Bohn is well known around JILA for his study of the physics of baseball, i.e., comparisons of the distances traveled by batted balls stored at different relative humidities before being put into play. Bohn’s long-standing interest in baseball has included playing on the JILA Monsters team with Jin, Cornell, Coach “Lew” (Heather Lewandowski) and other JILAns in the City of Boulder’s summer softball program.
Bohn also likes to ski and spend lots of time being a dad. He and Jin liked to take their daughter to interesting places around the world such as Paris where she practiced drawing the Eiffel Tower, Austria’s mountains where she got to see cows from the chair lift, and China where she met her mother’s cousins and walked on the Great Wall. Since September of 2016 when Jin passed away, Bohn has focused much of his considerable energy on being a devoted single dad.