During his August trip to Budapest, physics professor Francesco Iachello attended two meetings of the European Physical Society. He also took home its prestigious physics prize.

“In the first ceremony they gave me the medal and in the second they gave me the check,” Iachello said.

At the meetings, the European Physical Society awarded Iachello the Lise Meinter Prize for Nuclear Science. He won the award for his theory of supersymmetry, which was proven experimentally three years ago.

Iachello said supersymmetry, which analyzes the motion of single and paired constituents of an atom, is a very unusual type of symmetry.

“It’s a very complicated kind of symmetry,” Iachello said. “It’s like on a dance floor, you have pairs and individuals.”

Supersymmetry has become very popular since a group of German, French and Belgian researchers confirmed the theory experimentally in 1999, Iachello said.

Iachello’s colleagues said the concept of supersymmetry has been very influential in the field.

“In the world of theoretical nuclear physics in the past 25 years, this is the most important research,” Physics chairman Ramamurti Shankar said.

Richard Casten, director of the Wright Nuclear Structure Laboratory, said in an e-mail that Iachello’s work has revolutionized understanding of nuclei.

“His string of discoveries, starting as early as the mid 1970s, and continuing till today, has ushered in a new approach to the structure of nuclei that provides elegant solutions to problems that, otherwise, would take hours of supercomputer time,” Casten said. “Yet, with his approach, as good or better solutions can be obtained just with pencil and paper in a few minutes or by computer in a couple of seconds.”

Casten said the simplicity of Iachello’s approach makes it easy to understand microscopic systems in matter.

Iachello started his work with symmetry in 1974 when he and Japanese physicist Akito Arima devised a model for how the protons and neutrons in an atom are paired together and move in an organized fashion.

“Order is associated with symmetry,” Iachello said. “We uncovered all the symmetries of the atomic nucleus.”

Iachello has also received the Bonner Prize of the American Physical Society in 1993. He has honorary doctorates from the University of Ferrara, Italy; the University of Sevilla, Spain; and an honorary professorship at Nanjing University, China.

Iachello has a joint appointment in the Chemistry Department to study molecular symmetry.

“I started developing some models for complex molecules, trying to use symmetry concept to study these molecules,” Iachello said.

Iachello said he is now working on critical point symmetry to analyze what happens when a system changes phase. Instead of being more complicated at the critical point, “all of the sudden it simplifies,” Iachello said.

He said his formulas for critical point symmetry are being checked experimentally at the nuclear lab.

The European Physical Society gives the Lise Meitner Prize every two years. Lise Meitner was an Austrian-born physicist who worked in Germany in the 1930s.

“She discovered fission of nuclei, but her work was not recognized,” Iachello said. “Only after her death was her work recognized.”