It is a powerful feeling to be able to measure and learn something basic about atoms. I want to facilitate this experience for my students.

Ibrahim Sulai

Professor Ibrahim Sulai, physics & astronomy, recalls the excitement of discovery when he was an undergraduate researching the collisional properties of molecules. "It is a powerful feeling to be able to measure and learn something basic about atoms," he says. "I want to facilitate this experience for my students."

Sulai's research focuses on quantum mechanics. Specifically, he measures the noise created by the atomic spin of neutrons or electrons, which gives an atom its magnetic properties. By examining the interactions of atoms with light, he measures fluctuations in the projection of atomic spins, or "spin noise."

Rubidium and ytterbium make especially good subjects, according to Sulai, who is creating a lab where he and his students can conduct tabletop experiments to measure spin noise more accurately. "As we know from Heisenberg's Uncertainty Principle, every measurement contains a margin of error," he says. Spin noise arises as a direct consequence of this principle.

Medical imaging is a prime example of technology that makes use of the magnetism created by atomic spin. "An electrocardiogram (ECG) measures electrical activity of the heart. And wherever there's an electrical current, there's an associated magnetic field," he explains. "Magnetocardiography (MCG) measures these fields and is preferable to an ECG in many cases because it can permeate matter. Fetal heart imaging as an excellent example of where a noninvasive MCG would be more desirable than an ECG for obvious reasons."

One of the challenges with atomic magnetic sensors is that spin noise sets the ultimate limit of their sensitivity, Sulai says. Understanding how to make these measurements more accurate will help with the design and creation of better sensors.

"The experimental sciences are beautiful. In some ways, they are a craft," says Sulai. "To ask questions and be able to design elegant ways of making measurements to illuminate the answers — what could be more rewarding?"

Posted Oct. 7, 2015