Atoms in the Dark

Humans can only be human. Atoms, on the other hand, can change form dramatically. At times they are particles. But at other times, particularly when there are relatively few of them around, they may behave as waves, existing in many places simultaneously. What precisely happens when an atom sheds its particle form and changes into a wavy guise? When does this happen and why? These basic questions, at the core of matter’s existence, are the research focus of Dr. Nir Davidson of the Weizmann Institute’s Physics of Complex Systems Department.

One major obstacle frustrates the quest to observe the behavior of individual atoms: they are extremely swift. They fly tirelessly at high speeds, covering several football fields in a second. To restrain them, Davidson constructs dark traps surrounded by walls of light waves. The atoms are driven into the traps using laser cannons that cool them (i.e., slow them down). The cooled atoms’ energy is insufficient to transport them through the walls of light; they can only travel inside the dark space within these walls, like billiard balls moving from one side of a table to the other.

Davidson recently succeeded in controlling the manner of movement of the trapped atoms and was able to determine whether it would be along an organized or a chaotic (unpredictable) course.Using this method he found that chaotic courses, surprisingly, often make it possible to study atoms more precisely than nonchaotic ones.

 

Dr. Davidson’s research is supported by the Levine Institute of Applied Science and the Cymerman-Jakubskind Fellowship Fund. He is the incumbent of the Rowland Schaefer Career Development Chair.