Probing the secrets of condensed matter

Eugene Demler is a long way from the high school art student he was when he lived in the Siberian Russian town of Novosibirsk.

The son of an applied physicist, Demler was interested in art and painting, but found his artistic skills couldn’t keep pace with his ambition.

That hasn’t been a problem with his second career choice: physics.

An expert in condensed matter physics, the study of forces and interactions that operate above the scale of the atom, Demler gained tenure earlier this year as a professor of physics.

Demler credits a high school physics teacher for keeping him from a life as a suffering artist. He’s tread an illustrious path since then, studying physics at the Lebedev Physical Institute in Moscow with Vitaly Ginzburg. Ginzburg won the 2003 Nobel Prize in physics for “pioneering contributions to the theory of superconductors and superfluids.”

Demler himself is continuing to work on superconductors as he examines what are referred to as “strongly correlated systems,” or systems where there are strong interactions between the particles, which include magnetic systems and superconductors.

Physics Department Chair John Huth said Demler’s work has spanned the field of condensed matter physics and his theories have made important predictions of how atoms work in optical lattices created by crossed laser beams. These lattices are important because they allow the study of the interactions of atoms in highly controlled environments, Huth said.

Huth said he was happy that Demler was promoted from the department’s junior ranks, and said that’s a sign of the effort the department is making both to hire top-flight junior faculty and to ensure they can rise to full professor.

Demler said he has many useful collaborations with other faculty members, both at Harvard and at the Massachusetts Institute of Technology, particularly on work with ultracold atoms, which can be used to model superconducting systems.

“This is a great place to be because of these cooperations,” Demler said.

Huth said Demler’s ability as a theorist to work collaboratively with experimentalists in the department is a strong advantage.

“We have a strong need for people who work in condensed matter physics,” Huth said. “The interaction between people like Eugene and experimentalists who work in this area is crucial to the health of a collaborative department.”

In examining superconductors, Demler is seeking to understand materials that at extremely low temperature have no resistance to the flow of electrons. By contrast, a normal copper wire conducts electricity well, but some of the electron’s energy is lost as it travels the length of the wire. With a wire made of a superconductor, none of the energy would be lost.

Demler is specifically looking at high-temperature superconductors, or materials that gain superconducting properties at much higher temperatures than conventional superconductors. Though these materials are called “high-temperature” superconductors, they still must be cooled far below room temperature, minus 140 degrees centigrade in one instance.

Demler’s work focuses on the theoretical side, but many of the systems he studies have important applications in industry. Demler’s teaching duties have made him more aware of those applications, an awareness he said fits with his desire to use physics to explain the world around him.

“There’s a lot of really interesting physics in the concepts behind gadgets,” Demler said.

Demler said that in many instances we don’t understand well what creates superconductivity. With greater understanding of the phenomena, he said, superconductors at higher temperatures, perhaps even room temperature, would become possible.

“I like physics because it is something that relates to the real world,” Demler said.

In physics, there are two ways of looking at the field, Demler said. The first is that physics is wonderful and useful because of the eventual applications of its findings. The second is that physics is elegant because of the beautiful theories that describe it.

“I think both are right,” Demler said.